Functional morphology and fiber types of the masseter muscles of two caviomorph rodents with contrasting lifestyles, Ctenomys talarum (Ctenomyidae) and Cavia aperea (Caviidae).

The aim of this work is the analysis of histochemical and morphometric properties of the masseter muscles of Ctenomys talarum and Cavia aperea. The former belongs to a subterranean rodent clade, Ctenomyidae, which has evolved a robust masticatory apparatus adapted to chisel-tooth digging and processing of abrasive grasses; C. aperea belongs to the family Caviidae, with relatively graceful jaws and mandibular musculatures, consistent with less mechanically challenging diets. Adult males were captured, immediately transported to the laboratory, and euthanized in a CO2 chamber. The musculus masseter superficialis and musculus masseter profundus on the left side of the animals were used to analyze the histochemical composition of the fiber types treated with myosin adenosine triphosphatase, succinate dehydrogenase and periodic acid Schiff. The mean fiber diameters, relative areas, and frequencies of each muscle fiber type were calculated. The mm. masseter superficialis and masseter profundus on the right side were used to measure the physiological cross-sectional area (PCSA). Based on this measurement, the internal force (F) was estimated. In the m. masseter profundus of both species and in the m. masseter superficialis of C. aperea intermediate fast oxidative-glycolytic fibers (FOGi) predominated. In the mm. masseter superficialis and masseter profundus of C. talarum the relative area of fast glycolytic (FG) fibers was greater than that of the muscles of C. aperea, whose main muscle fiber component is FOGi fibers. When corrected for body mass differences, PCSA was higher for the mm. masseter superficialis of C. talarum. This and the larger relative area of FG fibers, probably contributes to the exertion of large bite forces in C. talarum, as measured in previous studies.

Development of the urinary system in guinea pig females (Cavia porcellus) / Desenvolvimento do sistema urinário em fêmeas de porquinhos-da-índia (Cavia porcellus)

Guinea pigs are animal models widely used in research related to developmental biology. The objective of this work was to demonstrate the process of formation and differentiation of urinary organs in females of the species in the prenatal period. Four females were used at 25, 30, 45 and >65 DG (days of gestation). The animals were dissected, and then macroscopic and microscopic descriptions of the urinary organs were performed. At 25 DG metanephros were present in the urogenital crest into the abdominal cavity. Collecting ducts and glomerular precursor cells could be visualized. After this period, metanephros underwent microstructural modifications to form the kidneys at the end of the prenatal period. After 30 DG, the renal parenchyma already had a cortex, where the glomerulus and proximal convoluted tubules were present; and the medulla, where distal convoluted tubules, collecting ducts, and pelvis were present. The pelvis of each kidney was drained by the ureters. The ureters also underwent tissue differentiation to be differentiated (mucosa with transitional epithelium and lamina propria of connective tissue, muscular, and adventitia) at the end of the prenatal period. The urinary vesicle also underwent tissue changes to form the tunics similar to those found in the ureters, with emphasis on the greater volume of the muscular tunica and the lamina propria that constituted the submucosa in this organ. The pelvic urethra was evidenced by a mucosa lined by transitional epithelium, submucosa, muscular and adventitia. Finally, a partial clitoral urethra and a urethral meatus in the prepuce of the clitoris were also evidenced. The urethral channel began to form with the emergence of the urethral plate and the urethral groove at 30 DG and thereafter with the fusion of the urethral folds to form a partially channeled urethra in the clitoris. A urethral meatus was observed in the most distal portion of the clitoral tissue, formed by the fusion of the prepuce. It is concluded that the urinary organs of guinea pig have similar development to that described in domestic animals, except for the partial clitoral urethra and evident urethral meatus.(AU)

Os porquinhos-da-índia são modelos animais amplamente utilizados em pesquisas relacionadas a biologia do desenvolvimento. O objetivo deste trabalho foi demonstrar o processo de formação e diferenciação dos órgãos urinários em fêmeas da espécie no período pré-natal. Foram utilizadas quatro fêmeas aos 25, 30, 45 e >65 DG (dias de gestação). Os animais foram dissecados e então, realizaram-se descrições macroscópicas e microscópicas dos órgãos urinários. Aos 25 DG os metanefros estavam presentes na crista urogenital da cavidade abdominal. Podiam ser visualizados ductos coletores e células precursoras glomerulares. Após este período, os metanefros sofreram modificações microestruturais para formar os rins ao final do período pré-natal. Após os 30 DG, o parênquima renal já apresentava um córtex, onde estavam presentes os glomérulos e túbulos convolutos proximais, e a medula onde estavam presentes túbulos convolutos distais, ductos coletores e a pelve. A pelve de cada rim era drenada pelos ureteres. Os ureteres também sofreram diferenciação tecidual para estarem com suas túnicas diferenciadas (mucosa com epitélio de transição e lâmina própria de tecido conjuntivo; muscular; e, adventícia) ao final do período pré-natal. A vesícula urinária também passou por modificações teciduais para formar as túnicas semelhantes as dos ureteres, com destaque para o maior volume da túnica muscular e a lâmina própria que constituiu a submucosa neste órgão. Uma uretra pélvica foi evidenciada por uma mucosa revestida por epitélio de transição, submucosa, muscular e adventícia. Por último, uma uretra parcialmente clitoriana e um meato uretral no prepúcio do clitóris também foi evidenciado. O canal uretral começou a se formar com o aparecimento da placa uretral e do sulco uretral aos 30 DG e posteriormente com a fusão das pregas uretrais para formar uma uretra parcialmente canalizada no clitóris. Observou-se um meato uretral na porção mais distal do tecido clitoriano, formado pela fusão do prepúcio. Conclui-se que os órgãos urinários do porquinho-da-índia possuem desenvolvimento semelhante ao descrito em animais domésticos, com exceção da uretra parcialmente clitoriana e do meato uretral evidente.(AU)

Subplacental development in Galea spixii / Desenvolvimento subplacentário do preá (Galea spixii)

Animal models are essential to understand healthy human placentation. Guinea pig related rodents became on focus for such purposes. In particular, processes of trophoblast invasion are similar. The latter is associated with a specialized area, the subplacenta. Since previous results showed differences between the guinea pig and its close relative Galea spixii, we aimed to study subplacental development with more detail. We investigated 16 pregnant females of 14 to 55 days of gestation by means of histology, morphometrics, immunohistochemistry and electron microscopy. The overlap between the fetomaternal blood systems resulted as intimate, suggesting some exchange processes. Proliferation was revealed by three independent methods, being most active in early and mid-gestation, which was in accordance to former results. Though degeneration of tissues took place, the subplacenta was maintained towards term with access to the fetal vascularization, supporting a hypothesis about the release of substances to the fetal unit in advanced gestation. In contrast to other species, the extraplacental trophoblast showed a shift from syncytial streamers to giant cells during mid-gestation. Views on placentation in caviomorphs were influenced by the guinea pig, but our data supported recent studies that the subplacenta had a much greater placidity. In regard to subplacental grow, degeneration and likely also exchange processes, Galea and other species showed a more basal pattern of caviomorphs than the guinea pig. Such differences should be considered, when choosing most adequate animal models for special purposes in comparison to human placentation.(AU)

Modelos animais são essenciais para entender a placenta humana sadia. Neste sentido os roedores relacionados ao porquinho da índia tornaram-se foco para tal entendimento. Em particular, os processos de invasão trofoblástica são semelhantes. O último está associado a uma área especializada, a subplacenta. Uma vez que os resultados anteriores mostraram diferenças entre o porquinho da índia e seu relativo o preá, buscamos estudar o desenvolvimento subplacentário com mais detalhes. Pesquisamos 16 fêmeas gestantes de 14 a 55 dias de gestação por meio de histologia, morfometria, imuno-histoquímica e microscopia eletrônica. A sobreposição entre os sistemas sanguíneos materno e fetal apresentou-se com íntima relação, sugerindo alguns processos de troca. A proliferação foi revelada por três métodos independentes, sendo mais ativos no início e metade da gestação, o que corroborou com os resultados anteriores. Embora a degeneração dos tecidos tenha ocorrido, a subplacenta foi mantida até o termo gestacional com acesso à vascularização fetal, apoiando uma hipótese sobre a liberação de substâncias para a unidade fetal em gestação avançada. Em contraste com outras espécies, o trofoblasto extraplacentário mostrou uma mudança de flâmulas sinciciais para células gigantes durante a metade da gestação. As visualizações sobre a placentação em caviomorfos foram influenciadas pelo porquinho da índia, mas nossos dados apoiaram estudos recentes de que a subplacenta apresentava uma plasticidade muito maior. Em relação ao crescimento subplacentário, a degeneração e provavelmente também os processos de troca, o preá e outras espécies apresentaram um padrão mais basal de caviomorfos do que o porquinho da índia. Tais diferenças devem ser consideradas, ao escolher os modelos animais mais adequados para fins especiais em comparação com a placentação humana.(AU)

Validation of an immunocytochemical assay for immunophenotyping of lymphoma in guinea pigs (Cavia porcellus).

BACKGROUND: Lymphoma is an important disease of pet guinea pigs, although validation of immunophenotyping techniques based on cytologic or hematologic samples has not been reported. OBJECTIVE: To describe an immunocytochemical method for immunophenotyping of lymphoma (as either T- or B-cell) in guinea pigs, and to validate antibodies for this purpose. METHODS: Blood and tissues were obtained at the time of necropsy from laboratory guinea pigs and a privately owned dog (control) euthanized for reasons unrelated to lymphoproliferative disease. Fine-needle aspirates of enlarged peripheral lymph nodes were obtained from a case of spontaneous lymphoma in a pet guinea pig. Anti-CD3 and anti-Pax5 antibodies were validated by a combination of western blotting performed on splenic lysates of both the dog and guinea pigs, immunohistochemical studies on normal guinea pig tissues, and immunocytochemistry on normal guinea pig peripheral blood and splenic impression smears. RESULTS: The antibodies bound to antigens of an appropriate size in both the dog and guinea pig splenic lysates by Western blot analysis. Immunohistochemistry and immunocytochemistry demonstrated the expected distribution of putative T- and B-lymphocytes in normal tissues, peripheral blood, and splenic impression smears. As a proof-of-principle for its clinical utility, this immunocytochemical assay was used to diagnose a B-cell phenotype in a spontaneous lymphoma case in a pet guinea pig. CONCLUSIONS: Here, we validated an immunocytochemical method for immunophenotyping of lymphoma in guinea pigs as either a T- or B-cell phenotype. This enables future research into the clinical attributes of these subtypes and may ultimately improve both prognostication and therapy of lymphoma in guinea pigs.

Development of the central nervous system in guinea pig (Cavia porcellus, Rodentia, Caviidae) / Desenvolvimento do sistema nervoso central em guinea pig (Cavia porcellus, Rodentia, Caviidae)

This study describes the development of the central nervous system in guinea pigs from 12th day post conception (dpc) until birth. Totally, 41 embryos and fetuses were analyzed macroscopically and by means of light and electron microscopy. The neural tube closure was observed at day 14 and the development of the spinal cord and differentiation of the primitive central nervous system vesicles was on 20th dpc. Histologically, undifferentiated brain tissue was observed as a mass of mesenchymal tissue between 18th and 20th dpc, and at 25th dpc the tissue within the medullary canal had higher density. On day 30 the brain tissue was differentiated on day 30 and the spinal cord filling throughout the spinal canal, period from which it was possible to observe cerebral and cerebellar stratums. At day 45 intumescences were visualized and cerebral hemispheres were divided, with a clear division between white and gray matter in brain and cerebellum. Median sulcus of the dorsal spinal cord and the cauda equina were only evident on day 50. There were no significant structural differences in fetuses of 50 and 60 dpc, and animals at term were all lissencephalic. In conclusion, morphological studies of the nervous system in guinea pig can provide important information for clinical studies in humans, due to its high degree of neurological maturity in relation to its short gestation period, what can provide a good tool for neurological studies.(AU)

Este estudo descreve o desenvolvimento do sistema nervoso central em guinea pig do 12º dia pós-concepção (dpc) até ao nascimento. No total, 41 embriões e fetos foram analisados macroscopicamente e por microscopia de luz e eletrônica. O fechamento do tubo neural foi observado no dia 14 e o desenvolvimento da medula espinhal e diferenciação das vesículas primitivas do sistema nervoso central foram observados no dia 20. Histologicamente, o tecido cerebral indiferenciado foi observado como uma massa de tecido mesenquimal entre os dias 18 e 20 e no 25º dia o tecido no interior do canal medular apresentou maior densidade. No dia 30 o tecido cerebral apresentou-se diferenciado, período no qual a medula espinhal preenchia todo o canal vertebral e foi possível observar os estratos cerebral e cerebelar. No dia 45 as intumescências cervical e lombar foram visualizadas e os hemisférios cerebrais estavam divididos, com uma clara distinção entre substância branca e cinzenta no cérebro e cerebelo. O sulco mediano dorsal da medula espinhal e a cauda equina foram evidentes apenas no dia 50. Não houve diferenças estruturais significativas em fetos de 50 e 60 dpc e animais a termo eram todos lisencefálicos. Estudos morfológicos do sistema nervoso em guinea pig podem fornecer informações importantes para estudos clínicos em seres humanos devido ao alto grau de maturidade neurológica em relação ao seu período de gestação curto, fato que servir como excelente ferramenta em estudos neurológicos.(AU)

Ultrastructural analysis of the spermatogenesis in the guinea pig (Cavia porcellus) / Análise ultraestrutural da espermatogênese do porquinho-da-Índia (Cavia porcellus)

Understanding of the reproductive function is essential for both, the establishment of appropriate management systems, and for the use of new species as animal models. In this study, we used light and electron microscopy to characterize the sexual development stages of the guinea pig (Cavia porcellus) in specimens of 30, 45 and 90 days of age. We observed the differentiation of spermatocytes only through transmission electron microscopy in the leptotene, zygotene and pachytene phases of meiosis, in 30-day-old animals. During puberty, there was differentiation of the germinative epithelium and formation of the acrosome. Spermatozoa, however, were not detected. Thus, we could infer that puberty happens after 45 days of age. Sexual maturity was evident in 90-day-old specimens. Our results showed that changes in the testicular germinative epithelium during the postnatal sexual development in guinea pig led to morphological changes, including the ones related to the development of Leydig and Sertoli cells, which are directly related to puberty. In this work, we provide new morphological subsidies for a better understanding of reproductive parameters of this species, enabling its use as an animal model in the field of the reproductive biology.(AU)

A função reprodutiva é um fator de vital compreensão tanto para o estabelecimento de sistemas apropriados de manejo, quanto para o uso de novas espécies como modelos animais. Neste estudo através da microscopia de luz e eletrônica caracterizou-se a fase de desenvolvimento sexual do porquinho-da-Índia (Cavia porcellus) em espécimes de 30, 45 e 90 dias de desenvolvimento. Nos animais de 30 dias, a diferenciação dos espermatócitos foi visualizada somente na microscopia eletrônica de transmissão em leptóteno, zigóteno e paquíteno. Durante a puberdade, houve diferenciação do epitélio germinativo, formação do acrossoma, porém não foram evidenciados espermatozóides, assim, infere-se que a puberdade acontece a partir dos 45 dias de idade. A maturidade sexual foi evidente aos 90 dias de idade. Nossos resultados mostraram que ao longo do desenvolvimento sexual pós-natal do porquinho-da-Índia, mudanças no epitélio germinativo testicular levam há alterações morfológicas, inclusive com relação ao desenvolvimento das células de Sertoli e de Leydig, as quais estão diretamente relacionadas com a puberdade. Assim, novos subsídios morfológicos são fornecidos para um melhor entendimento dos parâmetros reprodutivos desta espécie, a fim de viabilizar sua utilização como modelo animal no campo da biologia reprodutiva.(AU)

Ramos colaterais do Arco aórtico do preá (Galea spixii Wagler, 1831) / Collateral branches of the aortic arch of galea (Galea spixii Wagler, 1831)

O preá é um roedor típico da caatinga pertencente à família Caviidae. Considerando a inexistência de dados sobre o arco aórtico do preá, foi realizado este estudo tendo como objetivo descrever os ramos colaterais do arco aórtico neste cavídeo, e dessa forma, contribuir com dados para biologia da espécie. Foram utilizados vinte preás machos provenientes de estudos anteriores e encontravam-se armazenados em freezer no Centro de Multiplicação de Animais Silvestres (CEMAS/UFERSA). Os animais foram descongelados, a cavidade torácica foi aberta, a aorta canulada e o sistema vascular lavado com solução salina e em seguida, injetado látex Neoprene corado com pigmento vermelho, amarelo ou branco. Posteriormente, os animais foram fixados em formol e depois de 72 horas, dissecados e analisados, sendo obtidos desenhos esquemáticos e os exemplares mais representativos fotografados. O arco aórtico do preá emitiu como ramos colaterais, o tronco braquiocefálico e a artéria subclávia esquerda. O tronco braquiocefálico originou na maioria das peças estudadas, a artéria carótida comum esquerda e o tronco braquiocarotídeo, do qual surgem as artérias subclávia direita e carótida comum direita. As artérias subclávias direita e esquerda em todos os animais estudados emitiram a artéria vertebral, a artéria torácica interna, a artéria cervical superficial, o tronco costocervical e a artéria axilar. O padrão da formação do arco aórtico do preá assemelhou-se ao observado em outros roedores, tais como no mocó, no porquinho-da-índia e na chinchila...

Galea spixii is a typical rodent of the caatinga belonging to the Caviidae family. Considering the lack of data on the aortic arch of the galea, this study aimed to describe the collateral branches of the aortic arch in this specie and to contributes to knowledge of its biology. Twenty males from previous studies were used which had been stored in a freezer at Multiplication Center of Wild Animals (CEMAS/UFERSA). The animals were thawed, the thoracic cavity was opened and the aorta cannulated vasculature was washed with saline and then injected with Neoprene latex colored with red pigment, yellow or white. Subsequently, the animals were fixed in formalin and after 72 hours dissected and analyzed, to obtain schematic drawings and the most representative samples were photographed. The cavy aortic arch issued as collateral branches, the brachiocephalic trunk and the left subclavian artery. The brachiocephalic trunk afforded in most of the specimens the left common carotid artery and the brachiocarotid trunk, where the right subclavian and right common carotid arteries arise. The right and left subclavian arteries in all animals studied issued the vertebral artery, internal thoracic artery, superficial cervical artery costocervical trunk and axillary artery. The pattern of formation of the aortic arch of galea was similar to that observed in other rodents, such as the kerodon, the guinea pig and chinchilla....

Análise morfológica e funcional do processo espermatogênico em cobaios (Cavia porcellus) da pré-puberdade até a pós-puberdade / Morphological and functional analysis of spermatogenesis in guinea pigs (Cavia porcellus) from pre-puberty to post-puberty

Este estudo descreveu as análises morfológica e funcional do processo espermatogênico em cobaios (Cavia porcellus) de cinco (S5); seis (S6); nove (S9) e onze (S11) semanas de idade (N=5/grupo). Os aspectos analisados incluíram a contagem das populações celulares presentes no estádio 1 do ciclo do epitélio seminífero (CES), eficiência das mitoses espermatogoniais (RMi), produção meiótica (RMe), rendimento geral da espermatogênese (RGE), índice de células de Sertoli (ICS) e capacidade de suporte das células de Sertoli (CSCS). Os resultados mostraram que número médio de espermatogônias A, espermatócitos primários em pré-leptóteno/leptóteno, espermatócitos primários em paquíteno, células espermatogênicas totais e células de Sertoli mostraram variações numéricas em função da idade, entretanto, não detectadas estatisticamente, enquanto espermátides arredondadas aumentaram significativamente na puberdade e depois se estabilizaram. A produção espermatogênica de cobaios de 5 a 11 semanas não atingiu o ponto de estabilização e o RMi, RMe, RGE, ICS e CSCS mostraram variação numérica significativa em função da idade. Os resultados demonstraram que Cavia porcellus na pós-puberdade 2 são um modelo experimental vantajoso para estudos de processos de reconhecimento homólogos, alinhamento, e sinapses durante a prófase meiótica; o rendimento intrínseco da espermatogênese em cobaios é semelhante ao relatado para ratos Wistar, pacas e cutias (Dasyprocta sp.) e menor do que em preás, enquanto que a eficiência funcional das células de Sertoli é superior a de cutias e ratos Wistar e inferior à de pacas, rato espinhoso e catetos. Concluiu-se que em cobaios a espermatogênese está completamente estabelecida na semana 6 de idade, indicando a fase púbere do desenvolvimento sexual, e até a semana 11 eles não atingiram a produção espermática diária máxima e, portanto, a maturidade sexual.

This study describes the morphological and functional analysis of spermatogenesis in guinea pigs (Cavia porcellus) with five (W5), six (W6), nine (W9) and eleven (W11) weeks of age (n=5/group). The aspects analyzed include counts of cell populations present in stage 1 of seminiferous epithelium cycle (SEC), efficiency of spermatogonial mitosis (EMi), meiotic production (EMe), overall yield of spermatogenesis (EOS), Sertoli cell index (SCI) and carrying capacity of Sertoli cells (CCSC). The results showed that the average number of spermatogonia type A, primary spermatocytes in pré-leptóteno/leptóteno, primary spermatocytes in pachytene, total spermatogenic cells and Sertoli cells showed numerical variations according to age; however they were statistically not detected, while round spermatids increased significantly at puberty and then stabilized. The spermatogenic production of 5 to 11-week-old guinea pigs did not reach the stabilization point, and the RMi, RME, EOS, SCI and CCSC showed significant number variation as a function of age. The results demonstrate that Cavia porcellus in post-pubertal stage 2 are an advantageous experimental model to address studies on the processes of homologous recognition, alignment, and synapsis during meiotic prophase; intrinsic yield of spermatogenesis in guinea pigs is similar to Wistar rats, paca and agouti (Dasyprocta sp.) and lower than in cavies, whereas the functional efficiency of Sertoli cells is higher than in agouti and Wistar rats, and lower than in pacas, spiny rat and collared peccaries. We conclude that in guinea pigs the spermatogenesis is fully established at 6 weeks of age, indicating the pubertal stage of sexual development, and until week 11 they do not reach the maximum daily sperm production and therefore sexual maturity.

Descrição morfológica e morfométrica da glândula vesicular de cobaias durante o desenvolvimento pós-natal / Morphologic and morphometric description of the guinea pigs vesicular gland during postnatal development

Vesicular glands are essential for reproduction since their secretions affect sperm function. Guinea pigs (Cavia porcellus) are an excellent experimental model for studying vesicular glands, but no morphologic and morphometric data during its development are available. In the present study, the morphology (projections of the folds (PF) and epithelial tissue high (EH) of the mucosa) and the morphometry (mass (GM), volume (GV), length (GC), width of the portions cranial (CRW), medium (MW) and caudal (CAW)) of the vesicular glands were determined at 1, 3, 5, 8, and 11-weeks of age in male guinea pigs (n = 5/age group). In addition, body mass (BM), body length (BL) and height (BH) and organo-somatic index (OSI) were also determined and the simple correlation coefficient (r) was established between the variables. The glands were restricted to the pelvic cavity, and had its interior filled with a semi-solid mass and, after S8, they occupied also the abdominal cavity and the contents were increased significantly. The mucous membrane presented variable folding and simple columnar epithelium. BM, BL and BH increased continuously with age. GM, GV, GC and CAW did not change from 1 to 5-weeks of age, but increased at 8-weeks of age; GM, GV and LCA also increased at 11-weeks of age. OSI and PF increased at 8 and 11-weeks of age and EH at 5, 8 and 11-weeks of age. There was significant (r) between age, body and glandular parameters; OSI and GM at 8 and 11-weeks of age; age and PF, age and EH and between PF and EH. In conclusion, the guinea pigs vesicular glands followed morphology observed in rats and hamsters, but differed in some aspects from others histricomorfs, can be used as experimental model and its morphological and morphometric development can be divided into three phases: 1 to 5-weeks of age, when they are discrete; 6 to 8-weeks of age when they are generally sharp and >8-weeks of age, when there is an intense increase of the secretory capacity.

Glândulas vesiculares são essenciais para a reprodução, pois suas secreções afetam a função espermática. Cobaias (Cavia porcellus) são um excelente modelo experimental para estudo destas glândulas, contudo não existem dados morfológicos e morfométricos durante seu desenvolvimento. Neste estudo a morfologia (projeções das pregas (PP) e altura das células epiteliais (AE) da túnica mucosa) e a morfometria (massa (MG), volume (VG), comprimento (CG), largura das porções cranial (LCR), média (LM) e caudal (LCA)) das glândulas vesiculares foram determinadas em cobaios (N= 25) com uma (S1), três (S3), cinco (S5), oito (S8) e onze (S11) semanas de idade (N=5/grupo de idade). Em adição massa (MC), comprimento (CC) e altura (AC) corporais e o índice organo-somático (IOS) foram também determinados e o coeficiente de correlação (r) estabelecido entre as variáveis. As glândulas restringiam-se a cavidade pélvica e tinham seu interior repleto de uma massa semi-sólida e, após a S8, ocuparam também a cavidade abdominal e tiveram o conteúdo aumentado significativamente. A túnica mucosa era pregueada e forrada de um epitélio simples colunar. MC, CC e AC aumentaram continuamente com a idade. MG, VG, CG e LCA não se alteraram da S1 a S5 e aumentaram na S8; enquanto que MF, VG e LCA também aumentaram na S11. IOS e PP aumentaram na S8 e S11 e AE na S5, S8 e S11. Houve (r) significativo entre a idade, Bc e MFg,; IOS e MG na S8 e S11; idade e PP; idade e AE e entre PP e AE. Em conclusão, as glândulas vesiculares de cobaios seguiram o padrão morfológico observado em ratos e hamsters, mas diferiram em alguns aspectos de outros histricomorfos, podendo ser utilizadas como modelo experimental e seu desenvolvimento morfológico e morfométrico podem ser divididos em três fases: da S1 a S5, quando são discretos; da S6 a S8 de idade, quando são acentuados de maneira geral e após a S8, quando há incremento intenso da capacidade secretória.

Caracterização morfológica e frequência dos estádios do ciclo do epitélio seminífero em preás (Galea spixii Wagler, 1831) criados em cativeiro / Morphological characterization and frenquency of stages of the seminiferous epithelium cycle in captive bred Spix's yellow-toothed (Galea spixii Wagler, 1831)

Estudos baseados nas características testiculares estão altamente relacionados com a eficiência reprodutiva de varias espécies. Assim, o projeto desenvolvido teve como objetivo identificar as células do epitélio seminífero, caracterizar histologicamente suas associações, que formam os estádios, e determinar a frequência destes. Os fragmentos de testículos, com 30, 45, 60, 75, 90, 105, 120, 150 dias foram coletados no Centro de Multiplicação da Universidade Federal Rural do Semi-árido, Mossoró/ RN. Passando pelos processos de fixação, lavagens em soluções de concentrações crescentes de álcoois (70-100 por cento), desidratação em xilol, inclusão em Histosec®, preparação das lâminas histológicas, colorações em Hematoxilina e Eosina (HE) e suas fotomicrografias para a caracterização dos núcleos celulares do epitélio germinativo e a definição dos oitos estágios do ciclo do epitélio seminífero (CES) baseados no Método da Morfologia Tubular. Das faixas etárias analisadas todos os animais de 90-150 dias de idade apresentaram todos os estádios do CES. Os estádios I e III foram os que apresentaram maior e menor freqüência, respectivamente. Os animais caracterizados como pré-púberes (30 dias), púberes (45-90 dias de idade) e pós-púberes (105150 dias de idade) apresentaram os estádios I, VIII e IV com uma maior freqüência, respectivamente.

Studies based on the testicular characteristics are strongly associated with the reproductive efficiency of various species. Thus, the developed project aimed to identify the cells of the seminiferous epithelium, histologically characterized their associations, which form stages, and determine the frequency of these. The fragments of testes, 30, 45, 60, 75, 90, 105, 120, 150 days were collected Multiplication Center of Universidade Federal Rural do Semi-Árido, Mossoró, RN. Through the process of fixing, washing in solutions of increasing concentrations of alcohols (70-100 percent), dehydration in xylene, inclusion in Histosec ®, preparation of histological slides, stained with hematoxylin and eosin (HE) and their photomicrographs for the characterization of cell nuclei of the germinal epithelium and the definition of the eight stages of the seminiferous epithelium cycle (CES) based on the tubular morphology method. The different age groups all animals at 90 to 150 days of age showed all stages of the CES. Stages I and III showed the highest and lowest frequency, respectively. Animals categorized as prepubertal (30 days), pubertal (45 to 90 days old) and postpubertal (105 to 150 days of age) had stage I, IV and VIII with a higher frequency, respectively.

Estudio morfológico de la próstata y glándulas vesiculares de cobayo (Cavia porcellus) / Morphologic study of the prostate and vesicular glands of the guinea pig (Cavia porcellus)

El objetivo de esta investigación fue conocer la morfología de la próstata y glándula vesicular del cobayo (Cavia porcellus), describiéndose aspectos mesoscópicos, histológicos e histoquímicos. Se utilizaron 5 cobayos machos adultos (Cavia porcellus) sanos y alimentados con pellets, zanahorias y frutas ad libitum, en el Bioterio de la Universidad de La Frontera. Una vez sacrificados los animales, fueron aisladas las estructuras cuyos conductos terminaban en la uretra (conductos deferentes, glándulas vesiculares, glándulas coaguladoras, próstata y glándulas bulbouretrales). La próstata y las glándulas vesiculares fueron fijadas en formalina tamponada durante 24 horas y procesadas para su inclusión en paraplast. Se realizaron cortes seriados de 4 µm de grosor, los cuales fueron teñidos para los estudios histológico e histoquímicos. El análisis se realizó a través de un microscopio Carl Zeiss, Axiolab, con cámara Cannon, G6. La próstata se encuentra dorsal a la uretra y está constituída por una masa de tejido glandular cubierto por una delgada cápsula de tejido fibroso y células musculares lisas. Presenta dos lóbulos, derecho e izquierdo, unidos por un istmo dorsal a la uretra, por la cara ventral de cada lóbulo emergen de 8 a 10 pequeños conductos excretores. Histológicamente, está compuesta por unidades túbulo-alveolares recubiertos por epitelio secretor simple cúbico. Las glándulas vesiculares son dos estructuras túbulo-lobulares. Se ubican dorsal a la uretra, relacionándose ventralmente con los conductos deferentes y la cara dorsal de la vejiga. Histológicamente, presentan una capa mucosa con un epitelio cilíndrico de tipo secretor; una capa media constituida principalmente por tejido muscular liso y una capa externa serosa. La histoquímica, en ambas glándulas fue negativa para glucógeno, mucinas neutras y ácidas, sulfatadas y no sulfatadas, tanto en el tejido glandular como en su producto de secreción. La próstata y glándulas vesiculares del cobayo, guardan...

The objective of this investigation was to study the morphology of the prostate and vesicular gland of the guinea pig (Cavia porcellus), describing the mesoscopic, histological and histochemical aspects. Five healthy adult male guinea pigs (Cavia porcellus) were used. The animals received pellets, carrots and fruit ad libitum in the Biotherium of the Universidad de La Frontera. Once the animals were sacrificed the structures which ducts ended in the urethra, (vas deferens, vesicular glands, coagulator glands, prostate and bulbourethral glands) were isolated. The prostate and vesicular gland were fixed in buffered formalin during 24 hours and processed for their inclusion in paraplast. Serial cuts 4 µm thick were realized and stained for histological and histochemical studies, using a Carl Zeiss, Axiolab microscope with a Cannon G6 camera. The prostate is located dorsal to the urethra and is constituted by a mass of glandular tissue covered by a thin capsule of fibrous tissue and smooth muscular cells presenting two lobes, right and left joined to the urethra by a dorsal isthmus. Emerging through the ventral surface of each lobe are 8 to 10 small excretory ducts. Histologically it is composed by alveolar tubular units covered by a simple cubical secretor epithelium. The vesicular glands are two tubular lobular structures located dorsal to the urethra and are connected ventrally with the vas deferens and the dorsal surface of the bladder. Histologically presenting a mucous layer with a secretor type cylindrical epithelium, a medium layer namely constituted by smooth muscular tissue and a serous external layer. Histochemical reaction in both glands was negative for glycogen, for neutral and acid mucins, both sulfate and non sulfate, in the glandular tissue as well as the secretor product. The prostate and vesicular glands of the guinea pig are related to morphological aspects of other mammals. However, the differences found in the histochemical results suggest t...

Vestibular morphology in the German Waltzing guinea pig.

OBJECTIVE: The German waltzing guinea pig is a special strain of animal with a recessively inherited inner ear defect, resulting in deafness and a severe vestibular dysfunction. The hearing loss in the cochlea of the German strain is a result of a collapse of the Reissner membrane and the absence of scala media. The vestibular organ has not yet been described. MATERIALS AND METHODS: German waltzing guinea pigs (homozygote and heterozygote) of different ages ranging from embryologic age 25 days to adulthood were investigated. The living animals were tested with four different vestibular tests, and the fetuses were controlled according to breeding. The morphology of the vestibular parts (ampulla, saccule, and utricle) was observed by using the light and transmission electron microscopy. RESULTS: Collapse of the membranous labyrinth was found already at embryologic age 50 days and progressed over time. Vestibular dysfunction was noted already from birth. CONCLUSIONS: Vestibular atelectasis has been shown to have the same morphology as the reported vestibular dysfunction in the German waltzing guinea pig. Owing to this similarity, this animal can be a good model for vestibular research.

Descripción histológica e histoquímica del hígado de cobayo (Cavia porcellus) / Histological and histochemical description of the liver of the guinea pig (Cavia porcellus)

Si bien se han realizado estudios en el hígado de variadas especies, hay pocas investigaciones en cobayo, un roedor de fácil manejo y usado como animal de experimentación. El objetivo de este estudio fue describir en el hígado de cobayo, algunos aspectos histológicos e histoquímicos, lo cual permitiría realizar estudios experimentales. Se utilizaron 7 cobayos (Cavia porcellus) machos, obtenidos del Bioterio de la Universidad de La Frontera, Temuco, Chile. Las muestras fueron fijadas en formalina tamponada y procesadas para su inclusión en paraplast. Se realizaron cortes seriados de 5 um, los que fueron teñidos para estudios histológico e histoquímico. El hígado presentó una arquitectura lobulillar con límites poco definidos y espacios porta constituidos por estructuras vasculares y canaliculares biliares. Los cordones parenquimatosos estaban constituidos por hepatocitos de aspecto cuboide a poligonal que se disponían en forma radial desde la vena centro lobulillar. En las células hepáticas se demostró la presencia de glucógeno, mucinas neutras y hemosiderina. El diámetro medio del hepatocito fue de 17,25 um y el del núcleo fue de 7,31 um. El hígado de cobayo presenta similitudes con otras especies; sin embargo, para determinar parámetros morfológicos, se deben considerar: la edad, las condiciones medioambientales, la alimentación, etc.

While studies have been conducted in the liver of different species, there is little research on the guinea pig, a rodent of easy handling and used as anexperimentationanimal. The aim was to describe in the guinea pig liver, some histological and histochemical aspects, which would allowexperimental studies to be carried out. We used seven male guinea pigs (Cavia porcellus) obtained from the Bioterium of the Universidad de La Frontera, Temuco, Chile. Samples were fixed in buffered formalin and processed for inclusion in paraplast. Serial thick of 5 um were stained for histological and histochemical studies. The liver presented a lobular architecture vague borders and portal tracts consisting of vascular structures and canalicular bile. Parenchymal cords were composed of hepatocytes with a cuboidal to polygonal appearence, and radially distributed from the central lobular vein. It showed the presence of glucogen liver cells, and hemosiderin neutral mucins. The average diameter of hepatocytes was 17.25 um and the nucleous was of 7.31 um. The guinea pig liver shows similarities with other species, however, to determine morphological parameters, age, environmental conditions of animals, feeding, etc. must be considered.

Estereología renal en el cobayo (Cavia porcellus) / Renal stereology in the guinea pig (Cavia porcellus)

El cobayo (Cavia porcellus) es un roedor perteneciente al Orden Rodentia y a la Familia Caviidae, utilizado como animal de laboratorio y de consumo humano. Los parámetros cuantitativos del riñón entregan importante información de su morfofunción dada su labor en la homeostasis del organismo. El objetivo de este estudio fue describir el riñón de cobayo (Cavia porcellus), analizando las características estereológicas para futuros estudios experimentales. Se utilizaron 5 cobayos machos, obtenidos del Bioterio de la Universidad de La Frontera, Temuco, Chile. El riñón de cobayo pesó 3,2 g, aproximadamente. El riñón posee 140.298 glomérulos en total, Nv de 458 mm³, Vv de 7,89% y Sv de 3,58 mm²/ mm³. El volumen glomerular del riñón fue de 1,73 x 10(4)mm³ y el diámetro glomerular de 90 jm. Factores como especie, edad, peso corporal, peso y volumen renal, son importantes a considerar, ya que diferencian los resultados en investigaciones morfofuncionales.

The guinea pig, (Cavia porcellus) is a rodent pertaining to the Rodentia group and the Caviidae family, used as a laboratory animal and for human consumption. Quantitative parameters of the kidney provides important information of its morphofunction, given its labor in the organism's homeostasis. The aim or this study was to describe the kidney of the guinea pig (Cavia porcellus), analyzing the stereological characteristics for future experimental studies. Five male guinea pigs (Cavia porcellus) obtained from the Biotery of the Universidad de la Frontera, Temuco, Chile, were used. The kidney of the guinea pig weighed approximately 3.2g. The kidney has 140,298 total glomerulus, Nv of 458 mm³, Vv of 7.89% and Svof 3.58mm²/mm³. The glomerular volume of the kidney was of 1.73 x 10(4)mm³ and a glomerular diameter of 90 urn. Factors such as species, age, body weight and renal volume, are important to consider, as they differentiate the results in the morphofunctional investigations.

Conhecimento da anatomia da orelha de cobaias e ratos e sua aplicação na pesquisa otológica básica / Understanding the anatomy of ears from guinea pigs and rats and its use in basic otologic research

O uso de mostras animais é importante na pesquisa otológica e o conhecimento da anatomia de sua orelha permite sua utilização adequada. OBJETIVO: Estudar a anatomia da orelha da cobaia e do rato por microscopia óptica de luz (MOL) e microscopia eletrônica de varredura (MEV) e suas vantagens anatômicas na pesquisa otológica básica. MATERIAL E MÉTODO: Os ossos temporais, as bulas timpânicas e cócleas de três cobaias e ratos albinos foram fotografados e analisados ao MOL e MEV. RESULTADOS: O rato não é tão simples de manipular como a cobaia, e freqüentemente apresenta otite média. O rato apresenta uma junção frágil da bula timpânica, duas e meia espiras na cóclea e a membrana timpânica não veda todo o conduto auditivo externo. A cobaia possui uma bula inteiriça, martelo e bigorna fundidos e três e meia espiras na cóclea. Pela MEV a cobaia e o rato possuem Membrana Tectória, Membrana de Raissner e o Órgão de Corti. As Células de Hensen estão presentes somente na cobaia. CONCLUSÃO: A cobaia foi considerada de fácil manipulação para a microdissecção, pelo tamanho e rigidez do osso temporal, e para experimentos cirúrgicos envolvendo o estribo, janela oval e a membrana timpânica. Pela MEV nota-se semelhança entre cobaia e rato, podendo ambos serem utilizados em estudos da orelha interna.

The use of animal samples is important in otologic research and understanding the anatomy of their ears help make proper use of them in research projects. AIM: to study guinea pig's and rat's ears under light microscopy(LM) and scanning electron microscopy(SEM) and understand their anatomical advantages in basic otologic research. MATERIALS AND METHODS: The temporal bones, tympanic bullas and cochleas from three albino guinea pigs and rats were photographed and analyzed under LM and SEM. RESULTS: Rats aren't as simple to handle as guinea pigs, and often present with otitis media. Rats have a fragile junction of the tympanic bulla, two and half turns in the cochlea, and their tympanic membranes do not seal off the entire external auditory canal. Guinea pigs have full bullas, their incus and malleus are fused and they have three and half cochlear turns. Under SEM, guinea pigs and rats have Tectori Membrane, Raissner's Membrane and the Organ of Corti. Only guinea pigs have Hensen's Cells. CONCLUSION: Guinea pigs were considered easy to handle for microdissection purposes because of the size and robustness of their temporal bones, and for surgical experiments involving the stapes, the oval window and the tympanic membrane. Under SEM there are similarities guinea pigs and rats, and both can be used in inner ear studies.

Distribution of the interstitial Cajal-like cells in the gallbladder and extrahepatic biliary duct of the guinea-pig.

It has been suggested that interstitial Cajal-like cells (ICLC) may be involved in the spontaneous rhythmic electrical activities of the extrahepatic bile duct system. The present study investigated the distribution and characteristics of ICLC, which are immunopositive for CD117/ Kit receptor tyrosine kinase, using immunohistochemistry employing a monoclonal antibody raised against CD117/Kit on whole-mount preparations. The Kit-positive ICLC were examined using confocal laser scanning microscopy or fluorescence microscopy. ICLC, immunoreactive for Kit, were pleiomorphic and/or spindle-shaped cells with a few bipolar processes and distributed in the smooth muscle layers of the gallbladder and bile duct system. They were scattered in the hepatic duct, cystic duct and gallbladder as well as in the upper part of the common bile duct. The ICLC gradually increased in number and formed a completed cellular network in the lower part of the common bile duct and ampulla. The numbers of ICLC in the ampulla were similar to that of the duodenum and significantly much greater in number than in the gallbladder and bile ducts. The density of the ICLC in the common bile duct was significantly higher than that of other bile ducts. Our results suggested that the ICLC might contribute to the regulation of the spontaneous rhythmic contraction and development of motility disorders of the bile duct system.

Estereología comparativa entre el bazo del cuye (Cavia porcellus) y la rata (Rattus novergicus, Sprague Dawley) / Comparative stereology between the spleen of the Guinea pig (Cavia porcellus) and the rat (Rattus novergicus, Sprague Dawley)

El bazo es el órgano linfático periférico más grande del organismo y conocer sus aspectos morfológicos cuantitativos es importante para determinar posibles patologías. El objetivo del estudio fue determinar en dos especies: cuye (Cavia porcellus) y rata (Rattus novergicus Sprague Dawley), las características estereológicas del bazo, para obtener patrones de normalidad cuantitativos, los que servirán de base para futuros estudios morfofuncionales. Se utilizaron 5 bazos de cada especie, clínicamente sanos, obtenidos del Bioterio de la Universidad de La Frontera, Temuco, Chile. Los bazos fueron disecados y fijados en formalina tamponada al 10 por ciento y se determinó el volumen de éstos por el método de Scherle. Se obtuvieron 5 trozos por medio de Orientador los que fueron incluidos en paraplast. De cada trozo se obtuvieron 5 cortes histológicos de 3 micrones m de grosor y separados 200 micrones m entre sí, los cuales fueron teñidos con H-E. El porcentaje de pulpa roja, pulpa blanca y zona marginal en el bazo del cuye fue: 65,14 por ciento, 21,96 por ciento y 12,67 por ciento, respectivamente, y en la rata 53,9 por ciento de pulpa roja, 25,75 por ciento pulpa blanca y 15,87 por ciento de zona marginal. El número total de folículos fue 8,33 x 10² y 5,73x 10² para el cuye y la rata, respectivamente. Los resultados concuerdan con los obtenidos por otros autores, pudiéndose señalar un patrón cuantitativo del porcentaje de los compartimentos esplénicos de normalidad, que se podría considerar para futuros estudios morfo-funcionales.

The spleen is the largest peripheral lymphoid organ of the body so it is essential to know their morphological quantitative aspects in order to identify potential abnormalities. The aim of this study was to determine the parameters stereological spleen in normal two species commonly used in research such as the guinea pig and rat, to obtain quantitative patterns of normality, which will serve as a basis for future studies morphofunctional. 5 spleens were used for each species (Cavia porcellus and Rattus novergicus, Sprague Dawley) obtained from biotery the Universidad de La Frontera, Temuco, Chile. The spleens were dissected and fixed in formalin buffered to 10 percent and the volume is determined by the of Scherle method. 5 pieces were obtained through Orientator and these were included in paraplast. Each piece was performed histological cuts of 3 mm thick and separated 200 µm each other, which were stained with H-E. The percentage of redpulp, whitepulp and marginal zone in the Guinea pig was: 65.14 percent, 21.96 percent and 12.67 percent respectively, and in the rat 53.9 percent pulpred, 25.75 percent whitepulp and 15.87 percent of marginal zone. The total number of follicles was 8.33 x 10²follicles and 5.73 x 10² follicles for the Guinea pig and rat, respectively. The results are consistent with those obtained by other authors might identify a pattern of quantitative percentage of splenic compartments of normality that could be considered for future studies morpho-functional.

Regional changes in the spatio-temporal pattern of progesterone receptor (PR) expression in the guinea-pig genital tract as parturition approaches.

Normal parturition in guinea-pig involves changes in responsiveness of the genital tract to estrogen and progesterone. To better characterize endocrine control of guinea-pig parturition, protein and mRNA expression of estrogen receptor-alpha (ERalpha) and progesterone receptor (PR) were quantitatively evaluated in lower (LUS) and upper (UUS) uterine segments, cervix (C) and pubic symphyseal ligament (PSL) at three stages of pregnancy (established based on interpubic distance, 0mm: non-relaxed group, 4-6mm: 5 days before parturition, 11-14 mm: 1-2 days prepartum) and immediately after parturition. Towards parturition, no changes in PR mRNA levels were recorded in the UUS, whereas the LUS displayed a gradual increase. PR transcripts exhibited decreased levels during parturition in C and PSL. Levels of PR mRNA were increased in the LUS compared with that of the UUS only at parturition. Regarding protein expression during parturition, PR levels decreased in the UUS whereas in the LUS increased. In C and PSL, PR protein expression decreased 1-2 days prepartum and remained low during parturition. None of the regions studied showed changes in mRNA or protein expression of ERalpha. Therefore, functional regionalization of the guinea-pig genital tract is associated with changes in the spatio-temporal pattern of PR expression as parturition approaches.

Some features of the angioarchitecture of the testis in guinea-pig

Os ramos da artéria testicular em cobaio são uma artéria capsular principal e alguns ramos capsulares com disposições oblíqualongitudinal e transversa-longitudinal, mostrando um padrão distributivo variável em ambas as superfícies dos testículos. Os ramos subcapsulares se originam da própria artéria testicular ou da artéria capsular, sendo que estes ramos subcapsulares emitem vários outros ramos com disposição estratigrafica variável. Assim, se notam vasos sanguíneos extraalbugínicos colocados entre o estrato mesotelial e o próprio estrato denso da albugínea. Os vasos intra-albugínicos são caracterizados como seguimentos arteriasis e venosos dispostos na intimidade da albugínea testicular. Os vasos subcapsulares e intratesticulares sequentes aos anteriores aparecem na intimidade do testículo como pequenas artérias e veias, arteríolas e vênulas e capilares das redes capilares. Os vasos intratesticulares mostram um padrão complexo de disposição, sendo vistos, especialmente os capilares, com orientação espacial paralela ou perpendicular em relação aos túbulos seminíferos os quais circundam.

Intraepithelial alterations in the guinea pig lateral prostate at different ages after estradiol treatment.

The prostate is an accessory gland of the mammal reproductive system with great volume and high functional importance. Many works infer that, in addition to the androgenic ones, the estrogen can be associated with benign prostatic hyperplasia and prostatic cancer, but no conclusive evidence exists on the role of estrogen in normal prostatic and neoplastic tissue. The objective of this work was to evaluate the effects of chronic administration of estradiol benzoate on the lateral prostate of guinea pigs in the pre-pubescent, pubescent, post-pubescent and adult phases, with emphasis on the modifications provoked by this hormone on the glandular epithelium. The analyses of the estradiol-treated and control groups were investigated using histological procedures and transmission electron microscopy. The histopathological analysis of the lateral prostate in the treated group revealed areas where epithelial dysplasia was observed, assuming at some places a pattern of epithelial stratification characteristic of prostatic intraepithelial neoplasia. After ultrastructural analysis, the following were observed: enlargement of the internal membranes, heterogeneity in the cellular types, hypertrophy of the basal cells and apparent decrease of cytoplasmic organelles in some cells of the prostatic intraepithelial neoplasia. Still, a loss of cellular polarity was observed, along with nuclei of various forms, sizes and heights--as well as irregular chromatin distribution patterns. Such alterations were found mainly in pubescent, post-pubescent and adult animals subject to the chronic administration of estradiol. These findings reinforce the already existent data in understanding the role of estrogen in the etiology of prostatic diseases.