Morfologia e histoquímica das glândulas sexuais acessórias de Metachirus nudicaudatus, Didelphidae-Marsupialia / Morphology and histochemistry of accessory sex glands of Metachirus nudicaudatus, Didelphidae-Marsupialia

São descritas a morfologia e a distribuição de glicogênio e mucossubstâncias na próstata e nas glândulas bulbouretrais de Metachirus nudicaudatus (Geoffroy, 1803), única espécie do gênero. A próstata é envolvida pelas túnicas adventícia e muscular, e o estroma é formado pelo conjuntivo da mucosa uretral. O parênquima é constituído pelos túbulos secretores, disseminados na mucosa uretral, e que diferem histológica e histoquimicamente nos segmentos cranial, médio e caudal. Essas diferenças morfo-histoquímicas também são observadas nas partes externa, média e interna de cada túbulo. De um modo geral, os três segmentos prostáticos secretam mucossubstâncias neutras, porém o segmento caudal produz também glicogênio. Os três pares de glândulas bulbouretrais (laterais, intermédias e mediais) do Metachirus são envolvidas por uma cápsula conjuntiva e músculo estriado esquelético. O maior par é a bulbouretral lateral que é constituída por longos túbulos secretores de mucossubstâncias neutras. As bulbouretrais intermédias são formadas por túbulos ramificados, que produzem mucossubstâncias neutras, ácidas carboxiladas e ácidas sulfatadas. Os túbulo-ácinos ramificados das bulbouretrais mediais secretam mucossubstâncias neutras. O Metachirus não possui glândulas ampulares, vesículas seminais nem glândulas de coagulação.(AU)

This paper describes the morphology and distribution of glycogen and mucous substances in the prostate and the bulbourethral glands of Metachirus nudicaudatus (Geoffroy, 1803), the only species of the genus. The prostate is surrounded by the tunica adventitia, and muscle and stroma is formed by connective urethral mucosa. The glandular parenchyma consists of secretory tubules, scattered throughout the connective tissue of the urethral mucosa which differs histologically and histochemically in cranial, middle, and caudal segments of the prostate. These morpho-histochemical differences are also observed in the outer, middle and inner parts of the tubular epithelium of each prostatic segment. In general, prostatic segments secrete neutral mucous substances, and the caudal segment also produces glycogen. The three pairs of bulbourethral glands (lateral, intermediate and medial) are surrounded by a capsule of dense connective tissue and skeletal striated muscle. The glandular parenchyma is formed by tubules or branched tubuloacinar, covered by simple epithelium which is characteristic for each pair of glands. The lateral bulbourethral glands and the medial bulbourethral glands produce neutral mucous substances and the secretion of the intermediate bulbourethral glands consists of neutral mucous substances, carboxylated acids, and sulfated acids. The M. nudicaudatus does not have ampullary glands, seminal vesicles or coagulating glands.(AU)

Morfologia do escroto, do testículo e das vias espermáticas de Metachirus nudicaudatus (Geoffroy, 1803), Didelphidae-Marsupialia / Morphology of scrotum and testicle, and spermatic pathways of Metachirus nudicaudatus (Geoffroy, 1803), Didelphidae-Marsupialia

Foram utilizadas as gônadas e vias espermáticas de cinco animais machos, adultos em fase reprodutiva, da espécie Metachirus nudicaudatus Geoffroy 1803, única espécie do gênero, para descrever a morfologia do escroto, do testículo e das vias espermáticas. O Metachirus possui escroto pré-peniano e que contém os testículos permanentemente. A pele escrotal é não pigmentada e com poucos pelos e glândulas. A lâmina parietal da túnica vaginal apresenta-se pouco pigmentada. Os testículos são ovais e ligados ao epidídimo através do pedículo testículo-epididimário. Eles são envolvidos, externamente, pela cápsula testicular e sustentados por um estroma de natureza conjuntiva. As células intersticiais são os elementos predominantes no abundante tecido intertubular. Os túbulos seminíferos são largos, enovelados e envolvidos por uma túnica própria fibroelástica, contendo células mióides. O epitélio seminífero é formado pelas células espermatogênicas e de Sertoli intercaladas. Os túbulos seminíferos convergem em direção à extremidade capitata do testículo, ficando revestidos por apenas células de sustentação, caracterizando uma região de transição entre túbulos seminíferos e túbulos retos, ocupada por uma estrutura tipo "válvula" que obstrui parcialmente o lume tubular. Os túbulos retos reúnem-se para formar um único dúctulo eferente, que percorre uma pequena extensão intratesticular, atravessa a albugínea e penetra no pedículo testículo-epididimário. A parte flexuosa do dúctulo eferente forma um lóbulo separado na parte medial do corpo do epidídimo. O epidídimo é envolvido pela cápsula epididimária e constituído pelo ducto epididimário, que se encontra bastante enovelado. O ducto epididimário é revestido por epitélio simples colunar pseudoestratificado apresentando células principais, basais, apicais e de "halo claro". As células principais são predominantes e apresentam características morfológicas e histoquímicas que diferem ao longo do ducto, possibilitando a caracterização de nove diferentes zonas epididimárias. É no lume da zona sete (início da cauda) que começa o pareamento de espermatozoides. Esse fenômeno coincide com alterações morfológicas bem evidentes e uma maior quantidade de mucossubstâncias neutras é secretada nessa zona.O ducto deferente apresenta-se dividido em três partes: justa-epididimária, funicular e abdominal, baseando nas variações histológicas e histoquímicas de seu epitélio e componentes envolventes. O ducto deferente não apresenta ampola e nem cruza o ureter antes de desembocar na uretra. O funículo espermático contém o ducto deferente, artéria e veias testiculares, vasos linfáticos, nervos e um desenvolvido músculo cremáster. Seus componentes apresentam modificações estruturais nas regiões proximal, média e distal, sendo notável a peculiar rede admirável.(AU)

Gonads and sperm pathways of five adult male Metachirus nudicaudatus in the reproductive phase were used to describe the morphology of scrotum, testicle, and spermatic tract. M. nudicaudatus has a scrotum pre-penis which contains the testicles permanently. The scrotal skin is not pigmented and has few hairs and glands. The parietal vaginal tunic is slightly pigmented. The testicles are oval and connected to the epididymis by testicular-epididymal pedicle; they are surrounded externally by the testicular capsule and supported by a stroma of connective nature. Interstitial cells are the predominant elements in abundant intertubular tissue. The seminiferous tubules are wide, meandering and surrounded by a fibro-elastic coat, containing myoid cells. The seminiferous epithelium is composed of spermatogenic cells and Sertoli cells interspersed. The seminiferous tubules converge toward the end of the testis capitata, getting coated only support cells, featuring a transition region between the seminiferous tubules and straight tubules, occupied by a type "valve" structure that partially blocks the tubular lumen. Straight tubules together to form a single efferent ductule, which runs a small intra-testicular extent, penetrates through the tunica and the pedicle testis-epididymis. The flexuosa part of the efferent ductule forms a separate lobe in the medial part of the body of the epididymis. The epididymis is enveloped by a capsule and epididymal comprising the epididymal duct, which is quite entangled. The epididymal duct is lined by pseudostratified columnar epithelium with simple principal, basal, apical and "clear halo" cells. The main cells are prevalent and have morphological and histochemical differing characteristics along the duct, enabling to characterize nine different epididymal areas. In the lumen of the seventh area (top of tail) that starts the pairing of sperm. This phenomenon coincides well with morphological change and a larger amount of neutral muco-substances is secreted in that area. Vas deferens has three parts: fair-epididymal, abdominal and funicular part, based on histological and histochemical changes of the epithelium and surrounding components. The vas deferens has no bulb and even crosses the ureter before flowing into the urethra. The spermatic cord contains the vas deferens, testicular artery and veins, lymphatic vessels, nerves and developed cremaster muscle. Its components have structural changes in the proximal, middle and distal region, with a peculiar admirable network.(AU)

Antiglaucomatous effects of the activation of intrinsic Angiotensin-converting enzyme 2.

PURPOSE: To evaluate the effects of the activation of endogenous angiotensin-converting enzyme 2 (ACE2) using the compound diminazene aceturate (DIZE) in an experimental model of glaucoma in Wistar rats. METHODS: DIZE (1 mg/kg) was administered daily, either systemically or topically, and the IOP was measured weekly. To examine the role of the Mas receptor in the effects of DIZE, the Ang-(1-7) antagonist A-779 was co-administered. Drainage of the aqueous humor was evaluated by using scintigraphy. The analysis of ACE2 expression by immunohistochemistry and the counting of retinal ganglion cells (RGCs) were performed in histologic sections. Additionally, the nerve fiber structure was evaluated by transmission electron microscopy. RESULTS: The systemic administration and topical administration (in the form of eye drops) of DIZE increased the ACE2 expression in the eyes and significantly decreased the IOP of glaucomatous rats without changing the blood pressure. Importantly, this IOP-lowering action of DIZE was similar to the effects of dorzolamide. The antiglaucomatous effects of DIZE were blocked by A-779. Histologic analysis revealed that the reduction in the number of RGCs and the increase in the expression of caspase-3 in the RGC layer in glaucomatous animals were prevented by DIZE. This compound also prevented alterations in the cytoplasm of axons in glaucomatous rats. In addition to these neuroprotective effects, DIZE facilitated the drainage of the aqueous humor. CONCLUSIONS: Our results evidence the pathophysiologic relevance of the ocular ACE2/Ang-(1-7)/Mas axis of the renin-angiotensin system and, importantly, indicate that the activation of intrinsic ACE2 is a potential therapeutic strategy to treat glaucoma.

Differential expression and seasonal variation on aquaporins 1 and 9 in the male genital system of big fruit-eating bat Artibeus lituratus.

Efferent ductules and epididymis are involved in water and solute transport, which is indispensable for storage and maintenance of the sperm viability. The reabsorption process involves proteins such as aquaporins (AQP), which has been described in the male genital system of limited species, including primate, rodents, cats and dogs. To contribute with information about AQPs in the male system, here we investigated the distribution of AQP1 and AQP9 in the tropical bat Artibeus lituratus, along the annual reproductive cycle. A. lituratus is a seasonal breeder with natural variation in components of the androgen and estrogen responsive system, thus being a good model for exploring the AQPs modulation. AQP1 was found restricted to differentiating spermatids, efferent ductules epithelium and venular endothelia along the male tract. AQP9 was detected throughout the epididymis being more abundant in the cauda and ductus deferens, but was not found in testis, rete testis and efferent ductules. Contrasting with AQP1 which appear to be constitutively expressed, there was seasonal variation in AQP9 expression, which was reduced in regressed epididymis. The AQP9 does not appear to be modulated by estradiol or androgens, but possibly by other factor related to luminal sperm. The establishment of specific function for aquaporins in the male tract remains undetermined; however, the cellular distribution presently found are compatible with the main function of AQP1, as a selective water channel, and AQP9, which is a conduct for water and a plethora of neutral solutes present in the epididymis milieu such as glycerol and urea.

Seasonal variation in estrogen receptor ERα, but not ERß, androgen receptor and aromatase, in the efferent ductules and epididymis of the big fruit-eating bat Artibeus lituratus.

The efferent ductules (ED) are a major target for estrogens, which act via the estrogen receptors ERα (ESR1) and ERß (ESR2). ERα has been found in the ED of all species studied so far. However, in the epididymis (EP), the expression of ERα is controversial, as is data about the occurrence of aromatase in the epithelium lining the excurrent ducts. Therefore, to further investigate this estrogen-responsive system, we used a seasonal breeder, the Neotropical bat, Artibeus lituratus, in which testicular expression of androgen (AR) and estrogen (ER) receptors vary with reproductive phase. The localization of aromatase, ERα, ERß and AR in the ED and EP of A. lituratus was investigated. The results showed that aromatase, AR and ERß were distributed throughout the excurrent ducts and did not vary during the annual reproductive cycle. Conversely, ERα was detected primarily in the ED epithelium, had marked seasonal variation and was increased during regression, especially in the EP epithelium. The results suggest that ERα may be involved in preparing the male genital tract for recrudescence. Together, the data obtained under natural conditions emphasize that specific segments of the excurrent ducts downstream of the testis are the primary targets for estrogen action via ERα, which is similar to previous findings in animals lacking functional ERα.

Distribution of estrogen receptors (ERalpha and ERbeta) and androgen receptor in the testis of big fruit-eating bat Artibeus lituratus is cell- and stage-specific and increases during gonadal regression.

The testis is a classical target for androgens, especially testosterone, acting via androgen receptor (AR). Alternatively, androgens can be aromatized to produce estrogens which act via specific receptors ERalpha and ERbeta. Although estrogen action is essential for maintenance of male fertility, studies regarding the expression of ERalpha and ERbeta in testis are restricted to a few species of rodent and domestic animals, but rarely in wild species. To our knowledge, there are no studies in Chiroptera species. Chiroptera represent one of the largest and most diversified orders of mammals, which possess several interesting reproductive features, including higher affinity of SHBG for estrogens than androgens. Therefore, we thought that bats would constitute a good model for investigation of the role of estrogens in the male. In this study, the distribution of ERalpha, ERbeta and AR were evaluated in the testis of the big fruit-eating bat Artibeus lituratus and their levels were compared during reproductive and regressive periods. The results showed that ERalpha and AR were restricted to the somatic cells of the testis, whereas ERbeta was widely distributed in both somatic and spermatogenic cells in a cellular and stage-specific fashion. We demonstrated for the first time by immunohistochemistry, and confirmed by Western blotting, that ERbeta and AR increased during regression. The localization of ERalpha, ERbeta and AR in a seasonal, cell and stage-specific fashion in the testis of A. lituratus suggests that these receptors may play important roles in testis function during reproductive and non-reproductive periods.

Fine structure of macrophages in the testicular interstitial tissue of the White-belly opossum Didelphis albiventris

Os Macrófagos do tecido intersticial do testículo do gambá de barriga branca em períodos de nõo-acasalamento e acasalamento foram estudados usando-se a atividade endocítica e microscopia electr¶nica de transmissõo. Os macrófagos sõo numerosos, de forma irregular, possuindo longos e delgados prolongamentos citoplasmáticos. O núcleo é identificado com heterocromatina acolada ao envoltório muclear. O citoplasma possui numerosos lisosomas, alguns grupos de cisternas do retículo endoplasmático (REG), microtúbulos, mitocondrias e vesículas revestidas. Os macrófagos testiculares sõo endociticamente ativos na incorporaþõo de azul de tripan exógeno. Foram observadas junþ÷es peculiares entre macrófagos e células de Leydig, caracterizados por áreas eletrondensas no citoplasma de ambas as células e a presenþa de material eletrodenso no espaþo intercelular. Foram também observadas áreas densas no citoplasma dos macrófagos que sõo pontos de ancoragem de microfibrilas do estroma intesticial. Nõo foram evidenciadas diferenþas ultra-estruturais nos macrófagos em períodos de nõo-acasalamento e acasalamento. A fixaþõo dos macrófagos no estroma, sua atividade endocítica e íntimas associaþ÷es com células de Leydig sugerem que os macrófagos do tecido intesticial desempenham importante papel na funþõo testicular (AU)

Fine structure of macrophages in the testicular interstitial tissue of the White-belly opossum Didelphis albiventris

Os Macrófagos do tecido intersticial do testículo do gambá de barriga branca em períodos de näo-acasalamento e acasalamento foram estudados usando-se a atividade endocítica e microscopia electrônica de transmissäo. Os macrófagos säo numerosos, de forma irregular, possuindo longos e delgados prolongamentos citoplasmáticos. O núcleo é identificado com heterocromatina acolada ao envoltório muclear. O citoplasma possui numerosos lisosomas, alguns grupos de cisternas do retículo endoplasmático (REG), microtúbulos, mitocondrias e vesículas revestidas. Os macrófagos testiculares säo endociticamente ativos na incorporaçäo de azul de tripan exógeno. Foram observadas junçöes peculiares entre macrófagos e células de Leydig, caracterizados por áreas eletrondensas no citoplasma de ambas as células e a presença de material eletrodenso no espaço intercelular. Foram também observadas áreas densas no citoplasma dos macrófagos que säo pontos de ancoragem de microfibrilas do estroma intesticial. Näo foram evidenciadas diferenças ultra-estruturais nos macrófagos em períodos de näo-acasalamento e acasalamento. A fixaçäo dos macrófagos no estroma, sua atividade endocítica e íntimas associaçöes com células de Leydig sugerem que os macrófagos do tecido intesticial desempenham importante papel na funçäo testicular