Effect of Cryptorchidism on the Histomorphometry, Proliferation, Apoptosis, and Autophagy in Boar Testes

Abstract

Spontaneous unilateral cryptorchid boars have one testis in the abdomen or inguinal canal, causing its temperature to be at or near the body temperature, which impairs spermatogenesis, although the histomorphometry and molecular mechanisms underlying this process remain unclear. The aim of the present study was to determine the histomorphometry, proliferation, apoptosis, and autophagy alterations in spermatogonia and Sertoli cells in unilateral cryptorchid, scrotal (contrascrotal), and preweaning piglet (preweaning) testes. Histomorphometrical analysis of cryptorchid testes showed that the seminiferous tubules contained only Sertoli cells and a few spermatogonia, but did not contain post-meiotic germ cells. The number of spermatogonia markedly decreased, and the number of Sertoli cells did not change remarkably in cryptorchid testes. TUNEL assay results showed that apoptosis signals were predominantly observed in spermatogonia. In cryptorchid and contrascrotal testes, proliferating cell nuclear antigen (PCNA) and LC3 were located in spermatogonia. The number of PCNA-positive, TUNEL-positive, and LC3-positive germ cells was low, and the protein and mRNA levels of PCNA and LC3 were significantly decreased in cryptorchid testes. Taken together, the number of Sertoli cells did not change remarkably, whereas the number of germ cells decreased in the cryptorchid testes, compared with that in the contrascrotal testes. Insufficient proliferation, excessive apoptosis, and autophagy were involved in the regulation of the decrease in spermatogonia in cryptorchid boar testes.

Does Orexin B-Binding Receptor 2 for Orexins Regulate Testicular and Epididymal Functions in Normal and Cryptorchid Dogs?

“…In the cryptorchid male gonad, the localization of OXB and OX2R is restricted to Leydig and Sertoli cells. That might be attributed to detrimental effects on spermatogenesis, due to the undescending testis which ultimately leads to infertility as already reported (21,(35)(36)(37).…”

“…In contrast, OXB was demonstrated to not affect steroidogenesis (15,16), thus its role remains unclear. The regulation of male fertility and differentiation depends on the testicular descent from the abdomen to the scrotum (21). In this regard, cryptorchidism is a testicular dysgenesis has been described as the failure of one (unilateral) or both (bilateral) testes and the relative spermatic ducts to migrate into the scrotum (22)(23)(24), that is found particularly in dogs (involving, to a greater extent, the right gonad) (25)(26)(27), stallions (21,23,28), and humans (29).…”

“…The regulation of male fertility and differentiation depends on the testicular descent from the abdomen to the scrotum (21). In this regard, cryptorchidism is a testicular dysgenesis has been described as the failure of one (unilateral) or both (bilateral) testes and the relative spermatic ducts to migrate into the scrotum (22)(23)(24), that is found particularly in dogs (involving, to a greater extent, the right gonad) (25)(26)(27), stallions (21,23,28), and humans (29). The abnormal localization of the retained gonad and spermatic ducts causes impaired fertility and increases carcinogenesis associated to Sertoli cell tumors and seminomas (21).…”

“…In this regard, cryptorchidism is a testicular dysgenesis has been described as the failure of one (unilateral) or both (bilateral) testes and the relative spermatic ducts to migrate into the scrotum (22)(23)(24), that is found particularly in dogs (involving, to a greater extent, the right gonad) (25)(26)(27), stallions (21,23,28), and humans (29). The abnormal localization of the retained gonad and spermatic ducts causes impaired fertility and increases carcinogenesis associated to Sertoli cell tumors and seminomas (21). Histological alterations of testis and epididymis in normal and cryptorchid dogs have been previously described (30).…”

Protective effects of melatonin against physical injuries to testicular tissue: A systematic review and meta-analysis of animal models

“…Apoptosis, the programmed cell death, takes place during normal spermatogenesis. However, physical testicular injuries could elevate germ cell apoptosis and reduce seminiferous tubule diameter and sperm count ( 60 , 68 , 107 , 108 ). We observed that melatonin decreases apoptotic germ cells and ameliorates the detrimental impact of physical injuries on the testes.…”