Effect of zinc-free diet from weaning through puberty on the structure of the testis in albino rats, with a special focus on the Leydig cells

Zinc is an essential trace element. Many physiological processes would be impaired if zinc is not supplied in sufficient quantities in the diet. The aim of the work was to evaluate the effect of a zinc-free diet from weaning through puberty on the testicular structure of rats, with a special focus on the Leydig cells. Twenty weaned rats were divided into three groups. Group I [the control group] was fed a balanced diet. Group II [the zinc-free group] was fed a zinc-free diet for 3 months. Group III [the recovery group] was fed a zinc-free diet for 3 months, followed by a balanced diet for 1 month. At the end of the experiment, rats were weighed and blood samples were collected to measure the level of serum testosterone hormone. The testes were removed, weighed, and processed for light and transmission electron microscopic study. The zinc-free group showed a significant decrease in the mean body weight, testis weight, and serum testosterone level compared with the control group. The light and electron microscopic examination showed loss of most of the spermatogenic cells accompanied by variable degrees of degeneration in the form of karryorhexis and haphazard chromatin content. In the interstitial tissue, there was accumulation of exudate. Many Leydig cells showed dilated smooth endoplasmic reticulum and mitochondria. Others cells showed accumulation of glycogen. Most of these changes were reversed after receiving the balanced diet in the recovery group. A zinc-free diet altered the structure of both the seminiferous tubules and the Leydig cells. Most of these alterations were reversed by zinc replenishment. Zinc is considered an essential element for maintaining testicular structure and spermatogenesis process

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.

Testosterone level, nasal gland volume and Leydig cell morphometry in capybaras (Hydrochoerus hydrochaeris)

The testosterone levels with nasal gland volume and Leydig cell morphometry in sexually mature capybaras were compared using 10 adult capybaras, aging 28 months. Body and testicular weight were 50kg and 28g, respectively. The gonadosomatic index was 0.11±0.02 percent, while nasal gland volume was 34.12±13.04ml. Serum testosterone concentration was 25.07±14.73ng/ml. Leydig cell volume density and leydigosomatic index were, respectively, 28.8±8.3 percent and 0.030±0.007 percent. Total and individual Leydig cell volumes were 6.88±1.92ml and 2,228.14±272.59x10-12ml, respectively. Leydig cell numbers per testis and per gram of testis were, respectively, 3,079.4±719.9x10(6) and 115.09±31.78x10(6) cells. These results show that increase in serum testosterone concentration is correlated to a proportional increase of nasal gland and Leydig cell volume in capybaras.

Estimaram-se as correlações entre os níveis de testosterona e o volume da glândula nasal e a morfometria das células de Leydig no parênquima testicular de capivaras sexualmente maduras. Utilizaram-se 10 capivaras com aproximadamente 28 meses de idade e com peso médio corporal de 50kg e testicular de 28g. O índice gonadossomático e o volume médio da glândula nasal foram 0,11±0,02 por cento e 34,12±13,04ml, respectivamente, e a concentração sérica de testosterona 25,07±14,73ng/ml. A proporção volumétrica de células de Leydig e o índice leydigossomático foram 28,8± 8,3 por cento e 0,030±0,007 por cento, respectivamente. Os volumes total e individual de células de Leydig foram 6,88±1,92ml e 2228,14±272,59´10-12ml, respectivamente. O número de células de Leydig por testículo e por grama de testículo foram, respectivamente, 3079,4±719,9´10(6) e 115,09±31,78´10(6). Concluiu-se que o aumento dos níveis séricos de testosterona foi acompanhado por aumento proporcional do volume da glândula nasal de capivaras e que a concentração desse hormônio é tanto mais alta quanto maior for o volume da célula de Leydig.

Seasonal and experimental reactivation of Leydig cells of the bat Tadarida brasiliensis

The Leydig cells of the bat Tadarida brasiliensis, exhibit two well-defined periods of secretory activity that are intimately associated to the bat reproductive cycle. During the breeding season (August-September, late Winter and early Spring in the southern hemisphere), the interstitial tissue contains hypertrophic Leydig cells characterized ultrastructurally by the presence of pleomorphic mitochondria, depletion of lipid droplets, proliferation of membranes of agranular endoplasmic reticulum (AER) and enlargement of the Golgi complexes. By contrast, from Spring to Fall concurrent with regression of seminiferous tubules, the Leydig cells acquire a quiescent appearance with reduction in size and volume of AER membranes, atrophy of the Golgi complex and a massive storage of lipid droplets. The changes occurring in Leydig cells during the breeding season can be duplicated experimentally in non-breeding bats with exogenous stimulation with hCG. The gonadotropic treatment induces rapid changes in both interstitial cells and seminiferous tubules. The latter present evident signs of reactivation including proliferation of the spermatogenic cell line, permeation of the tubular lumen and depletion of lipid droplets. The Leydig cells display similar features to those found in the bat during the mating season at the peak of secretory activity. The bat T. brasiliensis is an excellent model to correlate the morphological organization of the Leydig cells with either seasonal fluctuations of its secretory activity or after experimental stimulation with gonadotropins.

Diferenças ultra-estruturais entre as células de Leydig de cavalo, jumento e seu híbrido / Ultrastructural differences between Leydig cells of horses: asses and hinnies

A ultra-estrutura das células de Leydig de cavalos, jumentos e burros foi comparada com o intuito de se estudar as diferenças morfológicas existentes. Todas as células estudadas apresentam um retículo endoplasmático liso bem desenvolvido, característico das células produtoras de hôrmonios esteróides. No cavalo, no entanto, esta organela aparentemente se apresenta mais abundante. As mitocondrias encontradas säo pequenas, redondas e numerosas. Nos jumentos e burros uma grande quantidade de microfilamentos aparece próximo ao núcleo. A funçäo destes filamentos é ainda desconhecida pois parece näo existir razäo para a presença de um citoesqueleto täo desenvolvido em células intersticiais, imóveis e sem funçäo de sustentaçäo, exceto, talvez, a relaçäo com o transporte de substâncias precursoras de esteróides e/ou organelas intracelulares

Célula de Leydig: ultra-estrutura e síntese de testosterona / Leydig cell: ultrastucture and testosterone synthesis

A Gonadotrofina LH prende-se a receptores específicos, localizados em microvilos da membrana citoplasmática, formando o complexo hormonio-receptor, que ativa o sistema adenilato ciclase e consequente sintese de AMPc. O nucleolite ativa fosfoquinases que fosforilam e sintetizam proteinas, necessárias para que seja produzida a testosterona. Gotículas de lipídeos, situadas no citoplasma da CL contêm a maior parte do colesterol esterificado que, após hidrólise, sob a forma de colesterol livre, é transportado por proteinas até a mitocôndria e nela, depois de ser levado até a membrana interna da crista, entra em contato com enzimas, que fazem a clivagem da cadeia lateral, transformando-o em pregnenolona. A pregnenolona é transportada para o REA, onde nova bateria de enzimas a transformará em testosterona, se o animal for adulto e suas células, consequentemente, maduras, ou em hormônios reduzidos, se a célula for imatura. Cada etapa do processo tem seus próprios mecanismos de autocontrole, secretando quantidades exatas de testosterona necessária à manutençäo da espermatogênese e caracteres sexuais secundários.

Histochemical and histological analysis of the leydig cells of cats treated with a supraphysiological dose of LH-RH analog

An LH-RH analog (des-Gly10, [D-Trp6]-LH-RH A) was administered to adult male cats for 67 days (20 microng/Kg,sc) in order to study its inhibitory effects on the structure of Leydig cells, as deter,mined by histological and histochemical-morphometric techniques. Histological examination showed that LH-RH A promotes a decrease in the volume of the interstitial tissue. In addition, Leydig cell nuclei exhibited marked structural alterations. Morphometric analyses utilizing histochemistry of the enzyme 3-ß-hydroxysteroid dehydrogenase (3-ß-HOST-D) as a marker of Leydig cells also demostrated a signifcant decrease of the relative volume occupied by the Leydig cells isn the testis

Modification of Johnson's method for metachromasia (toluidine blue) for testicular interstitial tissue

A modification of the Johnson's toluidine blue method for identification of testicular interstitial tissue elements is described. This consists in placing the tissue sections in Van Gieson's solution for 2 min after a 3 min immersion in an aqueous toluidine blue solution. Sharp histological distinctions between Leydig cells, mast cells and other connective tissue elements are obtained. The rounded Leydig cells with a large central nucleus and a prominent nucleolus show grayish yellow cytoplasm. The heterochromatin of Leydig cells nuclei stain a deep rose meanwhile it euchromatine is grayish yellow. Mast cells are full of large violet metachromatic granules which obscure nuclear and cytoplasmic features. Finally, fibroblasts and connective tissue collagen fibers stain yellow and pink respectively. An important advantage of this method is that the interstitial tissue components, specially the Leydig cells, retain the stain for a year or more

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