Abstract Neuroendocrine substances play essential roles in regulating the normal physiological functions of testicles. The purpose of this study is to explore the localization and effects of four neuroendocrine markers (NSE, SP, NFH and DβH) in normal and cryptorchid testes of Bactrian camels using western blotting, transmission electron microscopy, immunohistochemistry, and immunofluorescence methods. The results showed that cryptorchidism caused a reduction in layers of spermatogenic epithelium and decreased glycogen positivity in the basement membrane. The ultrastructure revealed that macrophages were always found around the Leydig cells, crowded with swelling mitochondria in cryptorchidism. Expression of NSE in the Leydig cells of cryptorchidism was significantly weakened compared to that in the normal group(p<0.01). We found that SP was always distributed along the nerve fibers in normal testes and was expressed in the Leydig cells of cryptorchidism. However, expression of NFH in the cryptorchidic tissue was strongly positive in the spermatogenic epithelium, with limited expression in Leydig cells and no expression in peritubular myoid cells. Therefore, the expression of DβH in the Sertoli cells was comparatively strong in both the normal and cryptorchidism groups. NFH and DβH expression was significantly increased in the cryptorchidism group compared with the normal group (p<0.01). These findings indicated that the underdeveloped seminiferous epithelium and pathological changes in cryptorchid tissue in Bactrian camels were potentially related to a disorder in glycoprotein metabolism. Our results suggest that NSE and SP could help judge the pathological changes of cryptorchidism. The present study provides the first evidence at the protein level for the existence of NFH and DβH in Sertoli and Leydig cells in Bactrian camel cryptorchidism and provides a more in-depth understanding of neuroendocrine regulation is crucial for animal cryptorchidism.

Abstract The Ziwuling black goat is an indigenously in China, their offspring are frequently affected by congenital cryptorchidism. The extracellular matrix (ECM) contains cytokines and growth factors that regulate the development of the testis, and component changes often result in pathological changes. Cryptorchidism is closely related to structural changes in ECM. In this study, the histochemical staining, immunohistochemical, immunofluorescence and Western blot combined with semi-quantitative analysis was used to describe the distribution of the important ECM components Collagen type IV (Col IV), laminin (LN)and heparan sulfate proteoglycans (HSPG) in the normal and cryptorchid testes of Ziwuling black goats. Results showed that: The histochemical staining showed that the dysplasia of seminiferous tubules and decreased number of Sertoli cells in cryptorchidism, as well as sparse collagen fiber. Meanwhile, the distribution of reticular fibers is relatively rich. Furthermore, the PAS and AB staining in the interstitial vessels and lamina propria of seminiferous tubules is weak. The immunohistochemical and immunofluorescence revealed that Col IV, LN was strongly expressed in Leydig, Sertoli cells of normal testes and moderately positive in the spermatogonia and spermatids, but HSPG was not expressed in the spermatogonia. However, cryptorchidism, the expression of Col IV, LN and HPSG in Leydig, Sertoli cells significantly decreased, as well as the expression of Col IV and LN in capillary endothelial cells, but HSPG was moderately expressed in spermatogonia. Based on these data, the underdevelopment of spermatogenic epithelium, decreased synthesis function of collagen fibers and Leydig cells develop usually in the cryptorchidism were shown to be closely related to the abnormal metabolism of Col IV and LN. The positive expressed of HSPG in the spermatogonia of cryptorchid testes is related to the compensatory development of spermatogonia.