E. Badia

The cycle of the seminiferous epithelium in Landrace boars

The present study describes the morphological features of the eight stages of the seminiferous epithelium in Landrace boars according to the tubular morphology method, as well as their relative frequency, length, and duration. In Landrace boars the pre-meiotic stages occupied the 31.9 +/- 19.9% of the spermatogenic cycle and had a total length of 1788.8 +/- 1153.0 microm and a duration of 2.78 days; they were mainly characterised by the presence of leptotene and pachytene spermatocytes and round spermatids. Meiotic stages, with a relative frequency of 16.4 +/- 6.8%, a length of 787.1 +/- 603.1 microm and a duration of 1.41 days, contained spermatocytes in advanced meiosis I and/or in meiosis II and elongating spermatids grouped in bundles. Post-meiotic stages occupied the 50.6 +/- 20.4% of the spermatogenic cycle and had a length of 2096.8 +/- 1175.0 microm and a duration of 4.37 days; the most important event of these stages was the spermiation, which included the complete remodelling of sperm head and tail and the releasing of spermatozoa into the lumen, as well as the formation of residual bodies. From data obtained we concluded that both germ cell associations of the stages maintain constant among Landrace boars, and that the relative frequency, length and duration of the stages were directly dependent of the cytological transformations on the seminiferous tubules.

Ultrastructural study of the boar seminiferous epithelium: changes in cryptorchidism.

ABSTRACT

Morphological and histochemical characteristics of the lamina propria in scrotal and abdominal testes from postpubertal boars: correlation with the appearance of the seminiferous epithelium

This study was undertaken to investigate the morphological characteristics and lectin affinity of the testicular lamina propria in healthy boars and in unilateral and bilateral abdominal cryptorchid boars. The lamina propria of scrotal testes from healthy boars and unilateral cryptorchid boars was constituted by an innermost noncellular layer, the basal lamina, and by 2 layers of peritubular cells, each separated by a fibrous layer. The noncellular layers contained collagen fibres and glycoconjugates with abundant N‐acetylgalactosamine, galactose, fucose, N‐acetylglucosamine and neuraminic acid residues. The inner peritubular cell layer was composed of myoid cells, the outer layer of fibroblasts. In the abdominal testes of unilateral and bilateral cryptorchid boars, the lamina propria of nondegenerating and degenerating seminiferous tubules appeared thickened due to an increased content of collagen fibres and glycoconjugates. Glycoconjugates showed decreased amounts of fucose, neuraminic acid and galactose, and increased amounts of N‐acetylglucosamine residues. The basal lamina formed infoldings toward the seminiferous epithelium and contained small cells. Both inner and outer peritubular cells were fibroblasts of immature appearance. In degenerated seminiferous tubules of bilateral cryptorchid boars, the lamina propria was composed of a thickened and collagenised basal lamina, without peritubular cells and with a low content of glycoconjugates. In scrotal testes, therefore, the lamina propria was implicated in tubular contractility and in mediating the communication and the substrate diffusion between seminiferous tubules and interstitial tissue. Cryptorchidism induced morphological and histochemical alterations in the lamina propria of abdominal testes, which may be linked to evidence from other studies of lack of tubular contractility and defective cell–cell communication and substrate diffusion. The severity of these anomalies correlated with the severity of Sertoli cell alterations.

Lectin histochemistry of the boar bulbourethral glands.

The present study describes, for the first time, the glycosidic content of boar bulbourethral glands using lectin histochemistry. Fourteen horseradish peroxidase- or digoxigenin-labelled lectins with different carbohydrate specificities were used in samples obtained from 3 healthy Landrace boars. The results obtained indicate that endpiece and duct cells synthesize and secrete mainly O-glycoproteins with alpha- and beta-D-N-acetylgalactosamine, beta-D-galactose-beta(1-->3)-D-N-acetylgalactosamine, D-N-acetylglucosamine and neuraminic acid residues. Glycoproteins secreted by bulbourethral glands have a role in the protection and lubrication of the urethra. In addition, they may be also involved in the regulation of the sperm metabolic activity and in the maintenance of the structural integrity of acrosomal and plasma membranes.

Morphologic and histochemical study of blood capillaries in boar testes: effects of abdominal cryptorchidism.

BACKGROUND Few data exist about the features of testicular microvasculature under normal and pathologic conditions. METHODS The morphology and lectin affinity of testicular capillaries were examined in healthy boars and in unilateral and bilateral abdominal cryptorchid boars. RESULTS The capillaries of scrotal testes contained a) the endothelial layer formed by two cells, b) the basal lamina constituted by collagen fibers and glycoconjugates with fucosyl, galactosyl, glucosyl, and neuraminic acid residues, and c) the pericyte layer formed by a single cell. These components participated in substrate exchange between blood and testicular tissue. The abdominal testes showed increased numbers of capillaries, which could exhibit a mature appearance, but also angiogenic or degenerative patterns. Angiogenesis was manifested in interstitial capillaries and was characterized by a) proliferation of endothelial cells, b) decreased thickness and decreased content of collagen fibers and glycoconjugates in the basal lamina, and c) lack of pericytes. Degenerative capillaries lay in association with seminiferous tubules and showed a) pyknotic endothelial cells; b) thickening, collagenization, and altered glycoconjugate content in the basal lamina; and c) increased development of pericytes. The angiogenesis of interstitial capillaries resulted in high vascular permeability, and the degeneration of intertubular capillaries led to defective substrate exchange between blood and seminiferous tubules. CONCLUSIONS Unilateral abdominal cryptorchidism did not alter the morphology and function of capillaries in the scrotal testis. Unilateral and bilateral abdominal cryptorchidism resulted in increased numbers and abnormal morphology and function of capillaries in abdominal testes. The proliferation of interstitial capillaries correlated with the immaturity of Leydig cells, and the degeneration of intertubular capillaries correlated with the thickening of the lamina propria.

Efficiency of the process of meiosis in scrotal testes of healthy boars and unilateral abdominal cryptorchid boars.

Unilateral abdominal cryptorchidism has usually been correlated with abnormalities in the spermatogenic activity of the scrotal testis. The present study describes the effects of unilateral abdominal cryptorchidism on the meiotic process in scrotal testes from postpubertal boars. The percentage of primary spermatocytes, secondary spermatocytes, and round spermatids was evaluated in testicular smears from scrotal testes of healthy boars and of right-sided unilateral abdominal cryptorchid boars. As compared to the scrotal testes of healthy boars, the scrotal testes of unilateral abdominal cryptorchid boars showed low transformation from primary to secondary spermatocytes (meiosis I), but normal transformation from secondary spermatocytes to round spermatids (meiosis II). The data obtained indicate that spontaneous unilateral abdominal cryptorchidism on the right side induced partial arrest of spermatogenesis at the primary spermatocyte stage that was attributed to anomalies in Sertoli-cell activity. Abnormal paracrine signals from altered Sertoli cells could have resulted in either disturbed mitosis, which led to the formation of spermatocytes with an abnormal DNA content, or abnormalities in the metabolic activity and the organization of the cytoskeleton of primary spermatocytes.