Melatonin Reduces Angiogenesis in Serous Papillary Ovarian Carcinoma of Ethanol-Preferring Rats.

Angiogenesis is a hallmark of ovarian cancer (OC); the ingrowth of blood vessels promotes rapid cell growth and the associated metastasis. Melatonin is a well-characterized indoleamine that possesses important anti-angiogenic properties in a set of aggressive solid tumors. Herein, we evaluated the role of melatonin therapy on the angiogenic signaling pathway in OC of an ethanol-preferring rat model that mimics the same pathophysiological conditions occurring in women. OC was chemically induced with a single injection of 7,12-dimethylbenz(a)anthracene (DMBA) under the ovarian bursa. After the rats developed serous papillary OC, half of the animals received intraperitoneal injections of melatonin (200 µg/100 g body weight/day) for 60 days. Melatonin-treated animals showed a significant reduction in OC size and microvessel density. Serum levels of melatonin were higher following therapy, and the expression of its receptor MT1 was significantly increased in OC-bearing rats, regardless of ethanol intake. TGFß1, a transforming growth factor-beta1, was reduced only after melatonin treatment. Importantly, vascular endothelial growth factor (VEGF) was severely reduced after melatonin therapy in animals given or not given ethanol. Conversely, the levels of VEGF receptor 1 (VEGFR1) was diminished after ethanol consumption, regardless of melatonin therapy, and VEGFR2 was only reduced following melatonin. Hypoxia-inducible factor (HIF)-1α was augmented with ethanol consumption, and, notably, melatonin significantly reduced their levels. Collectively, our results suggest that melatonin attenuates angiogenesis in OC in an animal model of ethanol consumption; this provides a possible complementary therapeutic opportunity for concurrent OC chemotherapy.

Quantitative Proteomic Profiling Reveals That Diverse Metabolic Pathways Are Influenced by Melatonin in an in Vivo Model of Ovarian Carcinoma.

To obtain more information into the molecular mechanisms underlying ovarian cancer (OC), we proposed a comparative proteomic analysis in animals receiving long-term melatonin as therapy or only vehicle using multidimensional protein identification combined with mass spectrometry. To induce tumor, a single dose of 100 µg 7,12-dimethylbenz(a)anthracene (DMBA) dissolved in 10 µL of sesame oil was injected under the left ovarian bursa of 20 Fischer 344 rats. The right ovaries were injected with sesame oil only. After tumors were developed, half of the animals received intraperitoneal administration of melatonin (200 µg/100g body weight/day) for 60 days. Melatonin therapy promoted down-regulation in numerous proteins involved in OC signaling pathways. The most significant portion of these proteins are involved in several metabolic processes, mainly those associated with mitochondrial systems, generation of metabolites and energy, hypoxia-inducible factor-1 signaling, antigen processing and presentation, endoplasmic reticulum stress-associated pathways, and cancer-related proteoglycans. A small number of proteins that were overexpressed by melatonin therapy included ATP synthase subunit ß, fatty acid-binding protein, and 10-kDa heat shock protein. Taken together, our findings suggest that melatonin therapy efficiently modulated important signaling pathways involved in OC, and these proteins might be further targets that should be explored in new therapeutic opportunities for OC.

Is the Epididymis a Series of Organs Placed Side By Side?

The mammalian epididymis is more than a highly convoluted tube divided into four regions: initial segment, caput, corpus and cauda. It is a highly segmented structure with each segment expressing its own and overlapping genes, proteins, and signal transduction pathways. Therefore, the epididymis may be viewed as a series of organs placed side by side. In this review we discuss the contributions of septa that divide the epididymis into segments and present hypotheses as to the mechanism by which septa form. The mechanisms of Wolffian duct segmentation are likened to the mechanisms of segmentation of the renal nephron and somites. The renal nephron may provide valuable clues as to how the Wolffian duct is patterned during development, whereas somitogenesis may provide clues as to the timing of the development of each segment. Emphasis is also placed upon how segments are differentially regulated, in support of the idea that the epididymis can be considered a series of multiple organs placed side by side. One region in particular, the initial segment, which consists of 2 or 4 segments in mice and rats, respectively, is unique with respect to its regulation and vascularity compared to other segments; loss of development of these segments leads to male infertility. Different ways of thinking about how the epididymis functions may provide new directions and ideas as to how sperm maturation takes place.

Apoptosis is triggered by melatonin in an in vivo model of ovarian carcinoma.

Apoptosis plays an important role in the treatment of cancer, and targeting apoptosis-related molecules in ovarian cancer (OC) is of great therapeutic value. Melatonin (Mel) is an indoleamine displaying several anti-cancer properties and has been reported to modulate apoptosis signaling in multiple tumor subtypes. We investigated OC and the role of Mel therapy on the pro-apoptotic (p53, BAX, caspase-3, and cleaved caspase-3) and anti-apoptotic (Bcl-2 and survivin) proteins in an ethanol (EtOH)-preferring rat model. To induce OC, the left ovary was injected directly with a single dose of 100 µg 7,12-dimethylbenz(a)anthracene dissolved in 10 µl of sesame oil under the bursa. Right ovaries were used as sham-surgery controls. After developing OC, half of the animals received i.p. injections of Mel (200 µg/100 g BW per day) for 60 days. Body weight gain, EtOH consumption, and energy intake were unaffected by the treatments. Interestingly, absolute and relative OC masses showed a significant reduction after Mel therapy, regardless of EtOH consumption. To accomplish OC-related apoptosis, we first observed that p53, BAX, caspase-3, and cleaved caspase-3 were downregulated in OC tissue while Bcl-2 and survivin were overexpressed. Notably, Mel therapy and EtOH intake promoted apoptosis along with the upregulation of p53, BAX, and cleaved caspase-3. Fragmentation of DNA observed by TUNEL-positive nuclei was also enhanced following Mel treatment. In addition, Bcl-2 was downregulated by the EtOH intake and lower survivin levels were observed after Mel therapy. Taken together, these results suggest that Mel induce apoptosis in OC cells of EtOH-preferring animals.

Gestational and lactational exposition to Di-N-butyl-phthalate (DBP) increases inflammation and preneoplastic lesions in prostate of wistar rats after carcinogenic N-methyl-N-nitrosourea (MNU) plus testosterone protocol.

In the present study, it was evaluated the susceptibility of prostatic lesions in male adult rats exposed to Di-N-butyl-phthalate during fetal and lactational periods and submitted to MNU plus testosterone carcinogenesis protocol. Pregnant females were distributed into four experimental groups: CN (negative control); CMNU (MNU control); TDBP100 (100 mg/kg of DBP); TDBP500 (500 mg/kg of DBP). Females from the TDBP groups received DBP, by gavage, from gestation day 15 (GD15) to postnatal day 21 (DPN21), while C animals received the vehicle (corn oil). CMNU, TDBP100, and TDBP500 groups received a single intraperitoneal injection of MNU (50 mg/kg) on the sixth postnatal week. After that, testosterone cypionate was administered subcutaneously two times a week (2 mg/kg) for 24 weeks. The animals were euthanized on PND220. Distal segment fragments of the ventral (VP) and dorsolateral prostate (DLP) were fixed and processed for histopathological analysis. Protein extracts from ventral prostate were obtained, and western blotting was performed to AR, ERα, MAPK (ERK1/2), and pan-AKT. Stereological analysis showed an increase in the epithelial compartment in TDBP100 and TDBP500 compared to CN. In general, there was increase in the incidence of inflammation and metaplasia/dysplasia in the DBP-treated groups, mainly in DLP, compared to CN and CMNU. Proliferation index was significant higher in TDBP500 and PIN (prostatic intraepithelial neoplasia) was more frequent in this group compared to CMNU. Western blot assays showed an increase in the expressions of AR and MAPK (ERK1/2) in the TDBP100 compared to CN, and ERα and AKT expressions were higher in the TDBP500 group compared do CN. These results showed that different doses of DBP during prostate organogenesis in Wistar rats could increase the incidence of premalignant lesions in initiated rats inducing distinct biological responses in the adulthood. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1185-1195, 2016.

Structure and histophysiological considerations on the arterial wall of the dog / Estructura y aspectos histofisiológicos de la pared arterial del perro

This paper described the architecture of the dog aortic arterial wall focused in the ascendant; thoracic descendent, and abdominal parts of the aorta. Furthermore, in this study we analyzed the wall structure of the right external iliac artery and the left vertebral artery of dog aiming to compare their architectural patterns with the aortic wall mainly in abdominal aortic part, which was structured by a mixed muscular and connective matrix equilibrated elements. The variables analyzed were the thickness of each mural layer; the number of elastic lamellae, mainly localized into the medial layer structure, and the diameters of each aortic segment. The aortic structure showed a typical elastic pattern in the ascendant and descendant thoracic parts, but in its abdominal segment a lesser presence of elastic lamellae permitted to classify it with a mixed mural composition. The aortic segments mainly presented variable amounts of smooth muscle cells and connective matrix assuming a meshwork pattern. Furthermore, smooth muscle cells were seen intermingled with connective lamellae and fibers forming the complex meshwork related, which certainly helped to guarantee the aortic mural integrity during the aortic blood flow.

El objetivo de este trabajo fue describir la estructura histológica de la aorta del perro adulto, a través del análisis morfométrico. Fueron estudiados los tres segmentos de la aorta, ascendente y descendente torácicos, y el segmento abdominal inferior a los riñones. Esta última porción presentó un patrón estructural mixto, con tejido muscular liso y conectivo, con equilibrio entre las células musculares lisas y el componente mural tipo estroma, con elementos fibrosos y laminillas elásticas. En las otras partes de la aorta, se observó el clásico patrón elástico en la estructura mural, con una mayor proporción de los componentes activos (musculares lisos) que los pasivos, o sea, laminillas y fibras conectivas. El número de las laminillas elásticas fue decreciente desde la aorta ascendente en dirección a la parte abdominal de la aorta. Los diámetros de los tres segmentos tiñeron de manera similar. La comparación entre la estructura mural de la aorta y la histología de la arteria iliaca interna derecha y arteria subclavia izquierda, ambas musculares, fueron analizadas de manera objetiva, encontrando diferencias en el patrón mural aórtico, principalmente en el segmento aórtico terminal.

Melatonin attenuates the TLR4-mediated inflammatory response through MyD88- and TRIF-dependent signaling pathways in an in vivo model of ovarian cancer.

BACKGROUND: Toll-like receptors (TLRs) are effector molecules expressed on the surface of ovarian cancer (OC) cells, but the functions of the TLR2/TLR4 signaling pathways in these cells remain unclear. Melatonin (mel) acts as an anti-inflammatory factor and has been reported to modulate TLRs in some aggressive tumor cell types. Therefore, we investigated OC and the effect of long-term mel therapy on the signaling pathways mediated by TLR2 and TLR4 via myeloid differentiation factor 88 (MyD88) and toll-like receptor-associated activator of interferon (TRIF) in an ethanol-preferring rat model. METHODS: To induce OC, the left ovary of animals either consuming 10% (v/v) ethanol or not was injected directly under the bursa with a single dose of 100 µg of 7,12-dimethylbenz(a)anthracene (DMBA) dissolved in 10 µL of sesame oil. The right ovaries were used as sham-surgery controls. After developing OC, half of the animals received i.p. injections of mel (200 µg/100 g b.w./day) for 60 days. RESULTS: Although mel therapy was unable to reduce TLR2 levels, it was able to suppress the OC-associated increase in the levels of the following proteins: TLR4, MyD88, nuclear factor kappa B (NFkB p65), inhibitor of NFkB alpha (IkBα), IkB kinase alpha (IKK-α), TNF receptor-associated factor 6 (TRAF6), TRIF, interferon regulatory factor 3 (IRF3), interferon ß (IFN-ß), tumor necrosis factor alpha (TNF-α), and interleukin (IL)-6. In addition, mel significantly attenuated the expression of IkBα, NFkB p65, TRIF and IRF-3, which are involved in TLR4-mediated signaling in OC during ethanol intake. CONCLUSION: Collectively, our results suggest that mel attenuates the TLR4-induced MyD88- and TRIF-dependent signaling pathways in ethanol-preferring rats with OC.

Melatonin Attenuates Her-2, p38 MAPK, p-AKT, and mTOR Levels in Ovarian Carcinoma of Ethanol-Preferring Rats.

Epidermal growth factor receptors 2 (Her-2) and 4 (Her-4) are closely associated with ovarian cancer (OC) progression and metastasis, and a more complete understanding of these signaling pathways allow the development of new therapeutic strategies. Melatonin (Mel) is recognized as having several anticancer properties and has been reported to modulate Her-2 system in aggressive tumors. Here, we investigated OC and the role of Mel therapy on the Her-2- and Her-4-signaling pathway related to downstream molecules in an ethanol-preferring rat model. To induce OC, the left ovary was injected directly with a single dose of 100 µg 7,12-dimethylbenz(a)anthracene (DMBA) dissolved in 10 µL of sesame oil under the bursa. Right ovaries were used as sham-surgery controls. After developing OC, half of the animals received i.p. injections of Mel (200 µg/100 g b.w./day) for 60 days. While Mel therapy was unable to reduce Her-4 and phosphoinositide 3-kinase (PI3K) levels, it was able to suppress the OC-related increase in the levels of the Her-2, p38 mitogen-activated protein kinases (p38 MAPK), protein kinase B (phospho-AKT), and mammalian target of rapamycin (mTOR). In addition, Mel significantly attenuated the expression of Her-2, p38 MAPK, and p-AKT, which are involved in OC signaling during ethanol intake. Collectively, our results suggest that Mel attenuates the Her-2-signaling pathway in OC of ethanol-preferring rats, providing an effective contribution for further development of adjuvant therapies.

Gestational protein restriction delays prostate morphogenesis in male rats.

Maternal malnutrition due to a low-protein diet is associated with functional disorders in adulthood, which may be related to embryonic development failures. The effects of gestational protein restriction on prostate morphogenesis in male offspring were investigated. Pregnant rat dams were divided into normoprotein (NP; fed a normal diet containing 17% protein) and hypoprotein (LP; fed a diet containing 6% protein) groups. On the day of birth (PND1), anogenital distance and bodyweight were measured in male pups. Seven males per experimental group (one male per litter) were killed, and the pelvic urethra was evaluated. LP offspring showed a significant reduction in bodyweight and anogenital distance on PND1. On three-dimensional reconstruction of the prostate, the number of prostatic buds was lower in LP than in NP males. Mesenchymal cells surrounding the buds were androgen-receptor positive, and the quantity and intensity of nucleus immunoreactivity was decreased in LP. The proliferation index was lower in LP than in NP prostatic buds. Immunoreactivity for α-actin in mesenchymal cells and that for epidermal growth factor receptor in epithelial cells was higher in NP than in LP. Our findings demonstrate that maternal protein restriction delays prostatic morphogenesis, probably because of considerable disruption in the epithelium-mesenchyme interaction.

Ultrastructure of the epithelium lining of cauda epididymidis in mongrel dogs / Ultraestrutura do epitélio de revestimento da cauda epididimária em cães sem raça definida

The epithelium lining of cauda epididymidis in mongrel dogs was examined by transmission electron microscopy. The epididymal epithelium is pseudostratified with stereocilia and is composed predominantly of principal and clear cells. Therefore, exist basal and apical cells. The principal and clear cells show features suggesting that they may be preferentially involved in absorptive and secretive functions. These results are compared with previously published data on the cauda epididymidis of other mammalian species, in order to understand the significance of the epididymis in sperm maturation.(AU)

O epitélio de revestimento da cauda epididimária em cães sem raça definida foi examinado através da microscopia eletrônica de transmissão. O epitélio epididimário é pseudoestratificado com estereocílios na borda luminal e é composto principalmente por células principais e claras. Além destes tipos, foi observado algumas células basais e apicais. As células principais e claras apresentaram características ultra-estruturais que sugerem que as mesmas estão envolvidas com funções absortivas e secretórias. Os resultados foram comparados com estudos prévios realizados na cauda do ducto epididimário de outros mamíferos, com o objetivo de melhor entender o papel do epidídimo na maturação espermática.(AU)

The expression of aquaporins 1 and 9 in adult rat epididymis is perturbed by chronic exposure to ethanol.

Aquaporins (AQPs), notably AQP-1 and AQP-9, may contribute to reabsorption of fluid and solute across the epididymis. Ethanol is related to be a toxicant affecting directly or indirectly the epididymis and the sperm motility. This study examined the expression of AQP-1 and AQP-9 in adult epididymis of the UChA and UChB 10% (v/v) ethanol-preferring rats, focusing the ethanol-induced hormonal disturbances upon the regulation of these AQPs. Chronic ethanol intake significantly decreased body weight, while UChA and UChB rats displayed a marked loss of epididymal weights. Both ethanol-consuming animals had a severe reduction of testosterone levels, whereas LH and 17ß-estradiol were unchanged. Throughout the epididymis, a strong reaction to AQP-1 was observed in myoid and endothelial cells of the UChB ethanol-preferring rats, differently from a moderate intensity in the initial segment of the UChA rats. In addition, AQP-9 showed a strong immunoreaction in the apical membrane of principal cells at initial segment. In cauda epididymis, the level of AQP-9 was reduced along the microvillus projections in both UChA and UChB rats compared to controls. We conclude that chronic ethanol consumption modulates the androgen levels, thereby modifying the expression pattern of AQP-1 and 9 in the epididymis.

Functional and morphological reproductive aspects in male rats exposed to di-n-butyl phthalate (DBP) in utero and during lactation.

The potential adverse reproductive effects, with emphasis on the epididymis, of in utero and lactational exposure to 100 mg/kg/d di-n-butyl phthalate (DBP) in adult male rat offspring were investigated. The fetal testis histopathology was also determined. The selected endpoints included reproductive organ weights, sperm motility and morphology, sperm epididymal transit time, sperm quantity in the testis and epididymis, hormonal status, fetal testis and epididymal histopathology and stereology, and androgen receptor (AR), aquaporin 9 (AQP9), and Ki-67 immunoreactivities. Pregnant females were divided into two groups: control (C) and treated (T). The treated females received DBP (100 mg/kg/d, by gavage) from gestation day (GD) 12 to postnatal day (PND) 21, while control dams received the vehicle. Some pregnant dams were killed by decapitation on GD20, and testes from male fetuses were collected for histopathogy. Male rats from other dams were killed at PND 90. Fetal testes from treated group showed Leydig-cell clusters, presence of multinucleated germinative cells, and increase of the interstitial component. Testosterone levels and reproductive organ weights were similar between the treated and control adult groups. DBP treatment did not markedly affect relative proportions of epithelial, stromal, or luminal compartments in the epididymis; sperm counts in the testis and epididymis; sperm transit time; or sperm morphology and motility in adult rats. The AR and AQP9 immunoreactivities and proliferation index were similar for the two groups. These results showed that fetal testes were affected by DBP as evidenced by testicular histopathologic alterations, but reproductive parameters and epididymal structure/function were not significantly altered in the adult animals exposed to 100 mg/kg DBP in utero and during lactation.

Vas deferens surface epithelium of Agouti paca: fine structural features / Epitelio del conducto deferente de Agouti paca: observaciones de estructura fina

The surface epithelium of the vas deferens of Agouti paca, a wild and large South American rodent, was basically formed by principal and basal cells being only the principal cells related to endocytosis processes and also secretion taking base on their cytoplasmic ultrastructural features. Principal cell of vas deferens epithelium were characterized mainly by presence of vesicles with several shapes, sizes and internalized content at their apical cytoplasm occurring smaller pits and pale small vesicles seen next to the apical brush border of microvillus. Moreover, coated vesicles, smooth surface vesicles and great vesicles; multivesicular bodies, endosomes and lysosomes were seen. Presence of an apocrine secretory apparatus was also viewed, showing apical cytoplasmic expansions protruding into the vas deferens luminal compartment. The basal flattened cells, without luminal surface contact, occurred next to the basement membrane of the ductus, and did no exhibit special ultrastructural features.

El epitelio que recubre la luz del conducto deferente de la laca (Agouti paca), un roedor silvestre de Sudamérica, está formado por células principales (P) y básales (B), en donde las células principales están asociadas a los procesos de endocitosis y secreción, teniendo una base en su característica ultraestructural citoplasmática. Las células principales de los vasos deferentes del epitelio se caracteriza principalmente por la presencia de vesículas con variadas formas, tamaños y contenido interior en su citoplasma apical produciendo pequeñas invaginaciones y pequeñas vesículas pálidas ubicadas continuas al borde en cepillo de las microveilosidades apicales. Además, fueron observados, vesículas de superficie lisa y vesículas de gran tamaño; órganos multivesiculares, endosomas y lisosomas. También se observó la presencia de un aparato secretor apocrino, con expansiones citoplasmáticas apicales que se protruyen en el compartimiento luminar del conducto deferente. Células básales aplanadas, sin contacto con la superficie luminal, se encuentran junto a la membrana basal del conducto, las que no presentan características ultraestructurales especiales.

Variabilidade sazonal no ducto epididimário de codorna doméstica: observações morfológicas / Seasonal variability in epididymal duct of the domestic quail: morphologic features

O ducto epididimário (DE) de codorna doméstica mostrou, ao longo do ano, variabilidade pequena, porém muito expressiva no outono, o qual corresponde à fase quiescente do ciclo testicular anual. A morfologia do DE na primavera foi, em termos, similar à verificada no verão e inverno. Nestas fases notaram-se aumento significante do calibre tubular do DE; estocagem intraluminal de espermatozóides e ocorrência de mitocôndrias, lamelas do RE, vesículas variáveis quanto à forma, dimensões e conteúdos e presença de alguns lisossomos localizados, principalmente, no citoplasma apical das células principais (P), no epitélio epididimário. Estas características ultra-estruturais das células P parecem ser indicativas da ocorrência de processos ativos de endocitose e de secreção micromerócrina. A quiescência outonal foi caracterizada pelo aspecto anfractuoso do DE; ausência de espermatozóides e pouco material intraluminal, observados à microscopia de luz. Características ultra-estruturais degenerativas foram verificadas ao nível do citoplasma supranuclear das células P epididimárias no outono.

Small but expressive variability was noted on the epididymidis duct (ED) of domestic quail along the year, with more evidence in autumn of the quiescent phase of the annual testis cycle in this species. Spring features of ED had a general similar pattern in summer and winter. They were characterized by enlargement of epididymis tubule, storage of spermatozoa into the luminal compartment and presence of mitochondria, ER lamellae, several variable vesicles, and lysosomes localized mainly on the apical cytoplasm of principal cells (P) of the epididymal epithelium. These P cells features indicated a process of endocytosis and perhaps protein secretion. Autumn quiescence was marked by a convolute pattern of the epididymis tubule, lacking of spermatozoa and small amount of exfoliate heterogeneous material inside the luminal compartment at light microscopy. Ultrastructural degenerative features mainly apical cytoplasmic debris were seen in the supranuclear cytoplasm of lining P cells.

Localización de proteínas totales y LDH en el epidídimo del hámster / Localization of total proteins and lactate dehydrogenase in hamster epididymis

La concentración de proteínas totales medidas a través de la fotocolorimetría y reportada como unidades por 100 mg de tejido, decreció desde el segmento inicial hacia la cola del epidídimo del hámster dorado, siendo significativa la diferencia numérica observada entre estas dos regiones. Esta observación estaba relacionada con el aumento de la síntesis y secreción de proteínas por el epitelio del epidídimo, siendo exportadas después hacia el lumen tubular en los segmentos proximales del epidídimo, especialmente a nivel del segmento inicial, ya obsevada en otros roedores. La actividad del LDH fue mayor en el segmento inicial y en la cola distal que en la cabeza y cuerpo del epidídimo, no obstante no haya sido observada ninguna diferencia significativa en los valores promedios. La intensa reacción del LDH observada en el segmento inicial y cola del epidídimo había sido relacionada con la expresiva actividad metabólica del epitelio, especialmente observada en estas regiones del conducto. Esta actividad metabólica permite la sobrevivencia y el metabolismo de los espermatozoides almacenados en la cola del epidídimo. Además, la baja actividad del LDH evidenciada en la cabeza y el cuerpo del epidídimo podría estar relacionada con la reducción progresiva de la glucólisis observada en la etapa inicial de maduración de los espermatozoides, siendo especialmente notoria en el cuerpo del epidídimo.

The concentration of total protein measured by photocolorimetric methodology and reported as units per 100 mg of tissue decreased from the initial segment to the cauda epididymidis of the Golden hamster, being significant the numeric difference observed between these two regions. This observation was related with an increased synthesis and secretion of proteins to the lumen in proximal segments of the epididymidis duct, mainly in initial segment, as proposed for other rodents. LDH activity was higher in initial segment and distal cauda than in the caput and corpus epididymidis, although no significant differences in mean values had been observed. The high LDH activity observed in initial segment and cauda epididymidis of hamster had been related to an expressive epithelium metabolic activity presented in these regions. This metabolic activity help to guarantee the survival of spermatozoa stored in cauda epididymidis. Furthermore, lower LDH activity noted in the caput and corpus epididymidis might be related with a progressive reduction of glycolysis in initial maturation step of spermatozoa mainly verified in corpus epididymidis.

Carotid arteries in the dog: structure and histophysiology

RESUMEN: El análisis de la estructura de las arterias carótidas, común, externa y interna en el perro sin raza definida, a través del microscopio fotónico mostró variabilidad en los valores promedios de los parámetros: diámetro vascular y grosor de las capas íntima, media y adventicia de cada arteria, respectivamente. El diámetro vascular no difirió significantemente entre las arterias carótidas interna y externa, pero mostró aumento significativo en la arteria carótida común, la cual da origen a los dos otros vasos sanguíneos. El grosor aumentado de las capas íntima y media de la arteria carótida común, más directamente sometida a la fuerza de la presión sistólica cardiaca, significó los ajustes constantes de la pared vascular a las alteraciones de presión y al estrés de deslizamiento controlado entre las capas de la pared arterial. El grosor de la adventicia de la arteria carótida interna fue significativamente mayor que la de las otras arterias carótidas (común y externa), las cuales, entre, sí no tuvieron diferencia con respecto de la adventicia. Estos resultados morfométricos estaban directamente correlacionados con las observaciones morfológicas de naturaleza cualitativa, especialmente, en relación al incremento relativo de la adventicia de la carótida interna ya apreciable en las microfotografías. Tal vez, la adventicia en la arteria carótida interna actúa como una capa conjuntiva protectora, durante el complejo proceso de avance de esta arteria desde su origen cervical hasta el nivel del canal carotídeo donde alcanza la cavidad craneana.