Stereological analysis of the New Zealand rabbits (Oryctolagus cuniculus) placenta.

The onset of gestation is characterized by growth, morphological and functional changes of the placenta. We aim to evaluate the placental compartments in New Zealand rabbits by means of stereological methods. The fetal and maternal portion of placenta (12, 14, 18 and 20 gestational days) was randomly sampled for the stereological analysis. Histological sections were scanned to estimate fetal (labyrinth and junctional) and maternal (decidua) compartment volumes. The total volume of the placenta for the ages of 12, 14, 18 and 20 days was, respectively, 320 mm3, 340 mm3, 940 mm3 and 1300 mm3. The volume of the labyrinth was 56 mm3, 119 mm3, 231 mm3 and 481 mm3, respectively. The volume of junctional zone was 75 mm3, 76 cm3, 238 mm3 and 314 mm3, respectively. The volume of decidua was 174 mm3, 143 mm3, 469 mm3 and 504 mm3, respectively. We concluded that the rabbit´s placenta compartments varied according to the gestational period, increasing continuously over the 20 gestational days. However, on the onset of the development of the placenta the decidua presented faster growth, whereas after the 20 days of development, the labyrinth developed more quickly. This study represents an aid to the understanding of placentation in humans.

Anatomic study of the arterial vascularization of the brain base of paca (Cuniculus paca) / Estudo anatômico da vascularização arterial da base do encéfalo da paca (Cuniculus paca)

Paca (Cuniculus paca Linnaeus, 1766), rodent belong to the Cuniculidae family, has encouraged numerous scientific researches and for this reason could be an experimental model in both human and veterinary areas. And recently, the economic exploitation of the meat cuts, has being direct implication in its zootechnical importance. However, no anatomical descriptions regarding the vascularization of the base of the brain in this rodent has being found. Thus, the aim of the present study was to describe the arteries and the pattern of the vasculature and to compare it with the other species already established in the literature. For this, five pacas, donated by the Unesp Jaboticabal Wildlife Sector, were euthanized followed by the vascular arterial system was injected with red-stained-centrifuged latex by the common carotid artery. After craniectomy, the brains were removed and the arteries were identified and, in addition, compared with those described in other animal species. The presence of the right and left vertebral arteries, close to the medulla oblongata, was detected, originating the basilar artery, which divided into the terminal branches of the right and left basilar artery. Ventral to the optic tract there was the right internal carotid artery and the left, dividing the middle cerebral artery and left rostral and right; dorsal to the optic chiasm, the medial branch of the rostral cerebral arteries was identified. Based on the results, it is concluded that the vascularization of the paca brain base is supplied by the carotid and vertebrobasilar system.(AU)

A paca (Cuniculus paca Linnaeus 1766), roedor da família Cuniculidae, tem encorajado inúmeras pesquisas científicas, tornando-a modelo experimental tanto na área humana quanto na veterinária, além da recente exploração econômica de seus cortes cárneos, que favoreceu diretamente sua importância zootécnica. No entanto, não há até o momento, descrições anatômicas referentes à padronização da vascularização da base do encéfalo neste roedor. Assim, o objetivo do presente trabalho foi realizar tal delineamento arterial nessa região do sistema nervoso central e compará-lo com as demais espécies já estabelecidas na literatura. Para isso, foram eutanasiadas cinco pacas doadas pelo setor de Animais Silvestres da Unesp Jaboticabal, as quais foram submetidas posteriormente à injeção de látex centrifugado e corante líquido xadrez vermelho, pela artéria carótida comum. Após craniectomia e segregação do encéfalo de todos os cadáveres, realizou-se a identificação das artérias presentes na base deste órgão e, ademais, comparação destas com as descritas cientificamente em outras espécies animais. Detectou-se a presença das artérias vertebral direita e esquerda, próximas à medula oblonga, originando a artéria basilar, que se dividiu nos ramos terminais da artéria basilar direito e esquerdo. Ventral ao trato óptico verificou-se a artéria carótida interna direita e esquerda dividindo-se na artéria cerebral média e rostral direita e esquerda; ainda, dorsal ao quiasma óptico, identificou-se o ramo medial das artérias cerebrais rostrais. Com base nos resultados obtidos, conclui-se que a vascularização da base do encéfalo da paca é suprida pelo sistema carotídeo e vertebro-basilar.(AU)

The effect of 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) on mice myocardial morphology / O efeito do 1-metil-4-fenil-1, 2, 3, 6 tetrahidropiridina (MPTP) na morfologia do miocárdio de camundongo

Studies have demonstrated sympathetic cardiac denervation in the MPTP mouse model. MPTP toxicity causes sympathetic nerve damage and depletion of heart norepinephrine. Previous evaluations of impairments in heart innervation have been based on imaging, electrophysiological and biochemical methods. However, these studies lacked information that can be obtained from morphoquantitative analyses. Thus, this study aimed to apply a design-based stereological method for evaluating the morphoquantitative alterations of myocardium following treatment with the neurotoxin MPTP in the C57/BL mouse. Our results showed that MPTP reduced the number of cardiomyocytes in the left ventricle.(AU)

Estudos têm demonstrado a desnervação simpática cardíaca no modelo da administração do MPTP em camundongo. A toxicidade do MPTP causa lesão ao nervo simpático e depleção da norepinefrina. As avaliações dos danos na inervação do coração são baseadas em métodos de imagem, eletrofisiológico e bioquímico. Contudo, estes estudos carecem de informações provenientes de análises morfoquantitativas. Assim, objetivou-se aplicar métodos estereológicos para avaliar as alterações morfoquantitativas do miocárdio após o tratamento com a neurotoxina MPTP no camundongo C57/BL. Nossos resultados mostraram que o MPTP causa redução no número de cardiomiócitos no ventrículo esquerdo.(AU)

Morfologia do órgão vomeronasal da paca (Cuniculus paca Linnaeus, 1766) / Morphology of the paca vomeronasal organ (Cuniculus paca Linnaeus, 1766)

O órgão vomeronasal é um receptor químico capaz de detectar feromônios e por essa razão está envolvido nos comportamentos reprodutivos, sociais e de defesa. A reprodução de pacas tem se destacado na área de comercialização de carne e para fins conservacionistas e de pesquisa, como modelo experimental. Diante da necessidade do detalhamento da morfologia do sistema olfatório secundário, o sistema vomeronasal, foi descrita a anatomia macroscópica, anatomia microscópica e topografia do órgão vomeronasal (OVN) da paca (Cuniculus paca). Foram utilizadas cinco pacas adultas do Setor de Animais Silvestres da FCAV, UNESP, Jaboticabal-SP. Após a eutanásia dos animais, a solução fixadora de formaldeído 10% em tampão fosfato de sódio (PBS) foi perfundida sistemicamente (via aorta ascendente). Mediante dissecação, o OVN foi localizado e individualizado para a descrição topográfica e anatômica. Posteriormente, foi isolado e incluído em parafina plástica. Cortes de cinco micrômetros foram corados com Hematoxilina-Eosina. O OVN encontra-se no assoalho da cavidade nasal em ambos os lados da base do septo nasal e está relacionado com o osso vômer, processos palatinos dos ossos pré-maxilar e maxilar. Rostralmente, comunica-se com a cavidade oral estabelecendo relação com a papila incisiva. É um órgão par com superfície irregular, levemente elíptico em secção transversal, apresentando coloração amarronzada repleta de vasos sanguíneos. À microscopia de luz, notou-se presença da cartilagem vomeronasal. O órgão é revestido por um epitélio não sensorial e neurossensorial.(AU)

The vomeronasal organ is a chemical receptor capable of detecting pheromones and for this reason is involved in reproductive, social and defense behaviors. The breeding of pacas has been highlighted in commercialization of meat and for conservation and research purposes, as an experimental model. Regarding the necessity of detailing the morphology of the secondary olfactory system, the vomeronasal system, the macroscopic anatomy, microscopic anatomy and topography of the vomeronasal organ (OVN) was described. Five adult pacas, from the wild animal Sector at FCAV, Unesp, Jaboticabal, SP were used. After the euthanasia, it was perfused 10% formaldehyde solution by ascendent aorta. The OVN was dissected for topographic and anatomical descriptions. Then, it was included in plastic paraffin. Five micrometres sections were collected and stained with hematoxylin and eosin. The OVN is located on the floor of the nasal cavity in both sides of the base of nasal septum and it was related to the vomer, palatine process of the premaxilar and maxilar bones. In rostral aspect, it has a communication with the oral cavity and with the incisive papilla. It is a paired organ with irregular surface. In transversal section is slight elliptical with brownish colour similar to a sponge full of blood vessels. By light microscopy, it was observed the vomeronasal cartilage. The organ is covered with non-sensorial and neurossensorial epithelia.(AU)

Morfologia e topografia do baço da paca ( Cuniculus paca Linnaeus, 1766) / Morphology and topography of the spleen of paca ( Cuniculus paca )

A paca é um grande roedor, presente em parte do território brasileiro e na América Latina, cuja importância está na crescente produção comercial de carne exótica e na pesquisa científica como um promissor modelo experimental. Assim, este trabalho objetivou-se descrever a morfologia e a topografia do baço da paca (Cuniculus paca). Foram utilizadas cinco pacas adultas, machos e fêmeas, fixadas em formaldeído a 10% e armazenados em solução salina a 30% para sua conservação. Na paca, o baço tem sua localização relacionada ao estômago, ao fígado, ao rim esquerdo, ao pâncreas e ao omento maior. Possui forma irregular, sendo mais longo do que largo, possui coloração avermelhada-escura e textura lisa. Quanto à descrição histológica, apresenta cápsula de tecido conjuntivo denso que emitiu trabéculas que se projetam no parênquima. A cápsula e as trabéculas apresentam fibras musculares lisas. O parênquima è composto pela polpa branca e polpa vermelha, esta última formada por seios e cordões esplênicos.(AU)

Paca is a large rodent, distributed in part of the Brazilian territory and in Latin America, whose importance is related to the crescent commercial production of exotic meat and in scientific research as a promising experimental model. The morphology and topography of the spleen of paca (Cuniculus paca) is described. Five adult pacas, male and female, were fixed with formaldehyde 10% and stored in 30% saline solution for preservation. The spleen of paca has the anatomical position related to stomach, liver, left kidney, pancreas and greater omentum. The spleenis irregular, longer than larger, with reddish-dark color and smooth texture. Related to the histological description, the spleen has capsule of dense connective tissue that emitted trabeculae projecting into the parenchyma. The capsule and trabeculae has smooth muscle fibers. The parenchyma is composed by the white and red pulp, the latter composed with sinusoids and splenic cords.(AU)

The quantification of testicular cells during the postnatal development in two Caviomorph rodents: the guinea pig (Cavia porcellus) and the cutia (Dasyprocta agouti)

ABSTRACT The germinative, Sertoli and Leydig cells of two caviomorph rodents (Cavia porcellus and Dasyprocta agouti) were counted as well as the estimation of the total volume of the testis and the total volume of seminiferous tubules and interstitium in prepubertal, pubertal and adult animals. The number of spermatogonia, spermatocytes and spermatids cells increased during the pubertal phase in both rodents, notably the spermatid cells. The spermatocyte and spermatid slightly decreased in the adult of both rodents, but the increment in spermatogonia cells number was seen, mainly in cutias. The number of Sertoli cells increased in pubertal rodents, but in the adult the number reduced. Substantial number of Leydig cells was counted in pubertal and adult guinea pigs. In cutias, the number of Leydig cells increased in pubertal phase and decline in adults. The design-based stereological method has proven to be unbiased and reliable to be applied in reproduction studies.

Anatomia microscópica e ultraestrutura do joelho da paca (Cuniculus paca Linnaeus, 1766) / Microscopic anatomy and ultrastructure of paca stifle (Cuniculus paca Linnaeus, 1766)

A paca (Cuniculus paca), um dos maiores roedores da fauna brasileira, possui características inerentes à sua espécie que podem contribuir como uma nova opção de animal experimental; assim, considerando-se que há crescente busca por modelos experimentais apropriados para ortopedia e pesquisas cirúrgicas, foram analisados e descritos em detalhes a anatomia microscópica e ultraestrutural do joelho desse roedor. Os ligamentos colaterais são constituídos por feixes de fibras colágenas arranjadas paralelamente e com trajeto ondulado. Os fibroblastos formavam fileiras paralelas às fibras colágenas; quanto aos ligamentos colaterais, estes apresentaram citoplasma imperceptível à avaliação por microscopia de luz, entretanto, em análise ultraestrutural verificou-se vários prolongamentos citoplasmáticos. Microscopicamente, as estruturas presentes no joelho da paca assemelham-se às dos animais domésticos, roedores e lagomorfos.(AU)

Paca (Cuniculus paca), one of the largest rodent of the Brazilian fauna, has characteristics inherent to the species that can contribute as a new experimental animal; so, considering that there is a growing search for experimental models suitable for orthopedic and surgical research, it was analyzed and described in detail the microscopic and ultrastructural anatomy of the stifle in this rodent. The collateral ligaments are composed of bundles of collagen fibers arranged in parallel and in wavy path. Fibroblasts formed parallel rows to the collagen fibers; concerning the collateral ligaments, they presented imperceptible cytoplasm at light microscopy, but at ultrastructure analysis they presented several cytoplasmic processes. At the microscopic level, the stifle of paca resembles the domestic animals, rodents and lagomorphs.(AU)

The quantification of testicular cells during the postnatal development in two Caviomorph rodents: the guinea pig (Cavia porcellus) and the cutia (Dasyprocta agouti).

The germinative, Sertoli and Leydig cells of two caviomorph rodents (Cavia porcellus and Dasyprocta agouti) were counted as well as the estimation of the total volume of the testis and the total volume of seminiferous tubules and interstitium in prepubertal, pubertal and adult animals. The number of spermatogonia, spermatocytes and spermatids cells increased during the pubertal phase in both rodents, notably the spermatid cells. The spermatocyte and spermatid slightly decreased in the adult of both rodents, but the increment in spermatogonia cells number was seen, mainly in cutias. The number of Sertoli cells increased in pubertal rodents, but in the adult the number reduced. Substantial number of Leydig cells was counted in pubertal and adult guinea pigs. In cutias, the number of Leydig cells increased in pubertal phase and decline in adults. The design-based stereological method has proven to be unbiased and reliable to be applied in reproduction studies.

Origem e distribuição das principais artérias do membro torácico de Cuniculus paca (Linnaeus, 1766) / Origin and distribution of the main arteries of the thoracic limb of Cuniculus paca (Linnaeus, 1766)

Objetivou-se descrever as artérias do membro torácico da paca (Cuniculos paca Linanaeus, 1766), mediante a dissecação da região. Para tanto, foram utilizadas 10 pacas adultas, machos ou fêmeas, pesando entre cinco e 10 kg do plantel de pacas do setor de Animais Silvestres da FCAV, Unesp, Jaboticabal-SP. Nos animais, injetou-se látex pela artéria carótida comum esquerda para preencher e corar todo o sistema arterial, seguido pela fixação em formaldeído a 10% e conservação em solução salina a 30% para dissecação anatômica das principais artérias do arco aórtico, braço e antebraço, identificando-se a origem e distribuição destes vasos. Os resultados foram foto documentados e discutidos com base na literatura sobre os animais domésticos, e roedores selvagens. De forma geral, as artérias do membro torácico da paca, assemelham-se com as dos carnívoros domésticos, do rato e da cobaia.(AU)

The aim of this study is to describe the arteries of the thoracic limb of paca (Cuniculos paca Linanaeus, 1766) by dissecting the region. We used 10 adult paca, males and females, weighting between five to 10 kg obtained from the breeding group at the Wild Animals Sector of FCAV, Unesp, Jaboticabal-SP. The animals were injected with latex by the left common carotid artery to fill and stain all the arterial system, followed by the fixation in 10% formaldehyde and preservation in 30% saline solution for anatomical dissection of the main arteries of the aortic arch, arm, forearm, identifying the origin and distribution of these vessels. The results were photodocumented and discussed based on literature about domestic animals and wild rodent. In general, the arteries of the thoracic limb of paca are similar to the domestic carnivores, rat and guinea pig.(AU)

Análise histoquímica das glândulas anexas do aparelho reprodutor do macho de paca (Cuniculus paca) / Histochemical analysis of the accessory glands of male paca (Cuniculus paca)

Paca is a wild rodent typical of the tropical region. In order to study this species with focus on the proper management and preservation, this study aims to characterize the histochemistry of the accessory glands of the reproductive tract of the male paca. For this purpose, histological sections were stained with Periodic Acid-Schiff (PAS), Alcian Blue (AB), PAS + AB e PAS + Amilase. In the histochemical reaction of the bulbouretral gland was found that the epithelium produces secretion rich in neutral and acid glycoproteins, glycosaminoglycans, and in some regions produces more than one type of secretion. The epithelium did not contain any glycogen. In the vesicular gland the epithelium had bush border stained by neutral glycoproteins, but no acid glycoproteins, glycogen or glycosaminoglycan. The coagulating gland showed small amount of neutral glycoproteins in the brush border of the epithelium, without glycogen. It is concludes that the accessory glands of paca have histochemical characteristics that share some similarity with other species of the Order Rodentia, with some glands with neutral and acid glycoproteins, mainly in the epithelium of the bulbouretral gland and in the brush border of the other glands.

A paca (Cuniculus paca) é um roedor típico de regiões tropicais. Com a finalidade de estudar esta espécie selvagem para manejo adequado e sua preservação, objetivou-se neste trabalho caracterizar a histoquímica das glândulas anexas do trato reprodutor do macho da paca. Para este fim, cortes histológicos dessas glândulas foram submetidas às reações histoquímicas com Ácido Periódico de Schiff (PAS), Alcian blue (AB), PAS. + AB. e PAS + Amilase. Na glândula bulbouretral foi constatado que o epitélio produz secreção rica em glicoproteínas neutras e ácidas, glicosaminoglicanas, e em algumas regiões produz mais de um tipo de secreção. Não foi observada a presença de glicogênio no epitélio. Na glândula vesicular, seu epitélio em borda em escova corou-se por glicoproteínas neutras e também por substância de composição desconhecida, não contendo glicoproteínas ácidas, glicogênio ou glicosaminoglicanas. Verificou-se presença de pequena quantidade de glicoproteínas ácidas e neutras na próstata, em especial na mucosa, além de glicoproteínas ácidas carboxiladas e sulfatadas em pequena quantidade no tecido conjuntivo da lâmina própria dessa glândula. Por fim, a glândula coaguladora apresentou pequena quantidade de glicoproteínas neutras na borda em escova de seu epitélio e substância de composição desconhecida, sendo ausente o glicogênio. Conclui-se que as glândulas anexas do trato reprodutor da paca apresentam características histoquímicas que compartilham certa similaridade com outras espécies da ordem Rodentia, com a presença de glicoproteínas neutras e ácidas em algumas glândulas, principalmente no epitélio da glândula bulbouretal e na borda em escova do epitélio das demais glândulas.

Análise histoquímica das glândulas anexas do aparelho reprodutor do macho de paca (Cuniculus paca) / Histochemical analysis of the accessory glands of male paca (Cuniculus paca)

A paca (Cuniculus paca) é um roedor típico de regiões tropicais. Com a finalidade de estudar esta espécie selvagem para manejo adequado e sua preservação, objetivou-se neste trabalho caracterizar a histoquímica das glândulas anexas do trato reprodutor do macho da paca. Para este fim, cortes histológicos dessas glândulas foram submetidas às reações histoquímicas com Ácido Periódico de Schiff (PAS), Alcian blue (AB), PAS. + AB. e PAS + Amilase. Na glândula bulbouretral foi constatado que o epitélio produz secreção rica em glicoproteínas neutras e ácidas, glicosaminoglicanas, e em algumas regiões produz mais de um tipo de secreção. Não foi observada a presença de glicogênio no epitélio. Na glândula vesicular, seu epitélio em borda em escova corou-se por glicoproteínas neutras e também por substância de composição desconhecida, não contendo glicoproteínas ácidas, glicogênio ou glicosaminoglicanas. Verificou-se presença de pequena quantidade de glicoproteínas ácidas e neutras na próstata, em especial na mucosa, além de glicoproteínas ácidas carboxiladas e sulfatadas em pequena quantidade no tecido conjuntivo da lâmina própria dessa glândula. Por fim, a glândula coaguladora apresentou pequena quantidade de glicoproteínas neutras na borda em escova de seu epitélio e substância de composição desconhecida, sendo ausente o glicogênio. Conclui-se que as glândulas anexas do trato reprodutor da paca apresentam características histoquímicas que compartilham certa similaridade com outras espécies da ordem Rodentia, com a presença de glicoproteínas neutras e ácidas em algumas glândulas, principalmente no epitélio da glândula bulbouretal e na borda em escova do epitélio das demais glândulas.(AU)

Paca is a wild rodent typical of the tropical region. In order to study this species with focus on the proper management and preservation, this study aims to characterize the histochemistry of the accessory glands of the reproductive tract of the male paca. For this purpose, histological sections were stained with Periodic Acid-Schiff (PAS), Alcian Blue (AB), PAS + AB e PAS + Amilase. In the histochemical reaction of the bulbouretral gland was found that the epithelium produces secretion rich in neutral and acid glycoproteins, glycosaminoglycans, and in some regions produces more than one type of secretion. The epithelium did not contain any glycogen. In the vesicular gland the epithelium had bush border stained by neutral glycoproteins, but no acid glycoproteins, glycogen or glycosaminoglycan. The coagulating gland showed small amount of neutral glycoproteins in the brush border of the epithelium, without glycogen. It is concludes that the accessory glands of paca have histochemical characteristics that share some similarity with other species of the Order Rodentia, with some glands with neutral and acid glycoproteins, mainly in the epithelium of the bulbouretral gland and in the brush border of the other glands.(AU)

Miologia do membro torácico da paca (Cuniculus paca) / Miology of the forelimb of paca (Cuniculus paca)

Objetivou-se descrever os músculos do membro torácico da paca (Cuniculus paca Linnaeus, 1766), mediante dissecação anatômica dessa região. Foram utilizadas cinco Cuniculus paca adultas, machos e fêmeas, pesando entre cinco e 10kg do plantel de pacas do setor de Animais Silvestres da FCAV, Unesp, Jaboticabal/SP. Os animais foram fixados em formoldeído a 10% e conservados em solução salina a 30% para dissecação anatômica da musculatura do ombro, braço e antebraço, identificando-se a origem e inserção de cada músculo. Os resultados foram fotodocumentados e discutidos com base na literatura sobre animais domésticos, ratos e cobaias. Salvo algumas variâncias na origem e inserção de cada músculo e na fusão dos ventres de alguns grupos musculares, de forma geral, a musculatura do ombro, braço e antebraço da paca assemelha-se a dos animais domésticos e a de outros roedores.

The objective was to describe the forelimb muscles of paca (Cuniculus paca Linnaeus, 1766), by anatomical dissection of this region. Five adult male and female C. paca, weighing 5-10kg, from the Department of Wild Animals, FCAV-Unesp, Jaboticabal/SP, were used. The animals were fixed in formaldehyde 10% and stored in saline 30% for anatomic dissection of the muscles of shoulder, arm and forearm, identifying the origin and insertion of each muscle. The results were photodocumented and discussed based on the literature of domestic animals, rats and guinea pigs. Unless some variances in the origin and insertion of each muscle and fusion of bellies of some muscle groups, in general, the muscles of shoulder, arm and forearm of paca resemble the ones of domestic animals and other rodents.

Miologia do membro pélvico da paca (Cuniculus paca Linnaeus, 1766) / The myology of the pelvic limb of paca (Cuniculus paca Linnaeus, 1766)

Objetivam-se descrever os músculos do membro pélvico da paca (Cuniculus paca Linnaeus, 1766), mediante dissecção anatômica dessa região. Foram utilizadas dez Cuniculus paca adultas, machos e fêmeas, pesando entre cinco e 10 kg do plantel de pacas do setor de Animais Silvestres da FCAV, Unesp, Jaboticabal/SP. Os animais foram fixados em formaldeído 10% e conservados em solução salina a 30% para dissecação anatômica da musculatura da pelve, coxa e perna, identificando-se a origem e inserção de cada músculo. Os resultados foram fotodocumentados e discutidos com base na literatura sobre animais domésticos, ratos e cobaias. Salvo algumas variâncias na origem e inserção de cada músculo e na fusão dos ventres de alguns grupos musculares, de forma geral, a musculatura da paca assemelha-se a dos animais domésticos e a de outros roedores.(AU)

This study aimed to describe the muscles of the pelvic limb of paca (Cuniculus paca Linnaeus, 1766) through anatomical dissection of this region. We used ten adult pacas, males and females, weighing 5 to 10 kg from the group of pacas at the sector of wild animals of FCAV, Unesp-Jaboticabal, SP. The animals were fixed with 10% formaldehyde and preserved in 30% saline solution for anatomical dissection of the pelvis, thigh and leg musculature, with identification of the origin and the insertion of each muscle. Photos were taken and the results were discussed based on the domestic animal, rat and guinea pig literature. In general, the paca musculature resembles the one of domestic animals and other rodents; but some variance in origin and insertion of each muscle and in the fusion of some muscular groups of the bellies was observed.(AU)

Shared and differential traits in the accessory olfactory bulb of caviomorph rodents with particular reference to the semiaquatic capybara.

The vomeronasal system is crucial for social and sexual communication in mammals. Two populations of vomeronasal sensory neurons, each expressing Gαi2 or Gαo proteins, send projections to glomeruli of the rostral or caudal accessory olfactory bulb, rAOB and cAOB, respectively. In rodents, the Gαi2- and Gαo-expressing vomeronasal pathways have shown differential responses to small/volatile vs. large/non-volatile semiochemicals, respectively. Moreover, early gene expression suggests predominant activation of rAOB and cAOB neurons in sexual vs. aggressive contexts, respectively. We recently described the AOB of Octodon degus, a semiarid-inhabiting diurnal caviomorph. Their AOB has a cell indentation between subdomains and the rAOB is twice the size of the cAOB. Moreover, their AOB receives innervation from the lateral aspect, contrasting with the medial innervation of all other mammals examined to date. Aiming to relate AOB anatomy with lifestyle, we performed a morphometric study on the AOB of the capybara, a semiaquatic caviomorph whose lifestyle differs remarkably from that of O. degus. Capybaras mate in water and scent-mark their surroundings with oily deposits, mostly for male-male communication. We found that, similar to O. degus, the AOB of capybaras shows a lateral innervation of the vomeronasal nerve, a cell indentation between subdomains and heterogeneous subdomains, but in contrast to O. degus the caudal portion is larger than the rostral one. We also observed that four other caviomorph species present a lateral AOB innervation and a cell indentation between AOB subdomains, suggesting that those traits could represent apomorphies of the group. We propose that although some AOB traits may be phylogenetically conserved in caviomorphs, ecological specializations may play an important role in shaping the AOB.

The developing left superior cervical ganglion of Pacas (Agouti paca).

In this study the main question investigated was the number and size of both binucleate and mononucleate superior cervical ganglion (SCG) neurons and, whether post-natal development would affect these parameters. Twenty left SCGs from 20 male pacas were used. Four different ages were investigated, that is newborn (4 days), young (45 days), adult (2 years), and aged animals (7 years). By using design-based stereological methods, that is the Cavalieri principle and a physical disector combined with serial sectioning, the total volume of ganglion and total number of mononucleate and binucleate neurons were estimated. Furthermore, the mean perikaryal (somal) volume of mononucleate and binucleate neurons was estimated using the vertical nucleator. The main findings of this study were a 154% increase in the SCG volume, a 95% increase in the total number of mononucleate SCG neurons and a 50% increase in the total volume of SCG neurons. In conclusion, apart from neuron number, different adaptive mechanisms may coexist in the autonomic nervous system to guarantee a functional homeostasis during ageing, which is not always associated with neuron losses.

Distinct tumor suppressor mechanisms evolve in rodent species that differ in size and lifespan.

Large, long-lived species experience more lifetime cell divisions and hence a greater risk of spontaneous tumor formation than smaller, short-lived species. Large, long-lived species are thus expected to evolve more elaborate tumor suppressor systems. In previous work, we showed that telomerase activity coevolves with body mass, but not lifespan, in rodents: telomerase activity is repressed in the somatic tissues of large rodent species but remains active in small ones. Without telomerase activity, the telomeres of replicating cells become progressively shorter until, at some critical length, cells stop dividing. Our findings therefore suggested that repression of telomerase activity mitigates the increased risk of cancer in larger-bodied species but not necessarily longer-lived ones. These findings imply that other tumor suppressor mechanisms must mitigate increased cancer risk in long-lived species. Here, we examined the proliferation of fibroblasts from 15 rodent species with diverse body sizes and lifespans. We show that, consistent with repressed telomerase activity, fibroblasts from large rodents undergo replicative senescence accompanied by telomere shortening and overexpression of p16(Ink4a) and p21(Cip1/Waf1) cycline-dependent kinase inhibitors. Interestingly, small rodents with different lifespans show a striking difference: cells from small shorter-lived species display continuous rapid proliferation, whereas cells from small long-lived species display continuous slow proliferation. We hypothesize that cells of small long-lived rodents, lacking replicative senescence, have evolved alternative tumor-suppressor mechanisms that prevent inappropriate cell division in vivo and slow cell growth in vitro. Thus, large-bodied species and small but long-lived species have evolved distinct tumor suppressor mechanisms.

Telomerase activity coevolves with body mass not lifespan.

In multicellular organisms, telomerase is required to maintain telomere length in the germline but is dispensable in the soma. Mice, for example, express telomerase in somatic and germline tissues, while humans express telomerase almost exclusively in the germline. As a result, when telomeres of human somatic cells reach a critical length the cells enter irreversible growth arrest called replicative senescence. Replicative senescence is believed to be an anticancer mechanism that limits cell proliferation. The difference between mice and humans led to the hypothesis that repression of telomerase in somatic cells has evolved as a tumor-suppressor adaptation in large, long-lived organisms. We tested whether regulation of telomerase activity coevolves with lifespan and body mass using comparative analysis of 15 rodent species with highly diverse lifespans and body masses. Here we show that telomerase activity does not coevolve with lifespan but instead coevolves with body mass: larger rodents repress telomerase activity in somatic cells. These results suggest that large body mass presents a greater risk of cancer than long lifespan, and large animals evolve repression of telomerase activity to mitigate that risk.

On the atrophy of the internal carotid artery in capybara.

Capybara might be a useful model for studying changes in cerebral circulation as the natural atrophy of the internal carotid artery (ICA) occurs in this animal at maturation. In this study, confocal and electron microscopy combined with immunohistochemical techniques were applied in order to reveal the changes in morphology and innervation to the proximal part of ICA in young (6-month-old) and mature (12-month-old) capybaras. Some features of the basilar artery (BA) were also revealed. The ICA of young animals degenerated to a ligamentous cord in mature animals. Immunolabelling positive for pan-neuronal marker protein gene product 9.5 but negative for tyrosine hydroxylase was observed in the proximal part of ICA at both ages examined. Axon varicosities positive for synaptophysin were present in the adventitia of ICA of young animals but were absent in the ligamentous cord of mature animals. In the ICA of young animals, adventitial connective tissue invaded the media suggesting that the process of regression of this artery began within the first 6 months of life. An increase in size of the BA was found in mature animals indicating increased blood flow in the vertebro-basilar system, possibly making capybara susceptible to cerebrovascular pathology (e.g. stroke). Capybara may therefore provide a natural model for studying adaptive responses to ICA regression/occlusion.