Testicular denervation in prepuberty rat inhibits seminiferous tubule development and spermatogenesis

In the adult rat, the superior spermatic nerve (SSN) and inferior spermatic nerve (ISN) are involved in regulating testosterone secretion and spermatogenesis, in addition to endocrine control mechanisms. However, there are currently few data on how the testis nerve supply regulates testicular development and related mechanisms. The present study was thus designed to investigate the regulating effects of testis nerve supply to testicular maturation, spermatogenesis and the involved mechanisms from prepuberty to adulthood in rats. We transected the SSNs and ISNs of rats on postnatal day (PD) 30 and then analyzed changes in testicular morphology and cauda epididymal sperm content, cell proliferation and apoptosis and primary spermatocyte meiosis on PD60 and PD90. The results demonstrated that testicular denervation significantly reduced testis mass, cauda epididymal sperm counts and serum testosterone concentrations. Proliferating cell nuclear antigen (PCNA) and cleaved caspase-3 immunohistochemistry staining proved that the denervation had no influence on the proliferation of spermatogonia and primary spermatocytes, but obviously promoted the apoptosis of round spermatids and Leydig cells. It is novel that denervation reduced the meiotic activation of zygotene and pachytene spermatocytes through the expression of synaptonemal complex protein 3 (SCP3)-a marker of meiosis. In addition, RT-PCR showed that testis denervation significantly decreased testis 3beta-hydroxysteroid dehydrogenase 1 (3beta-HSD1) and luteinizing hormone receptor (LHR) mRNA levels, but had no obvious influence on testis follicle stimulating hormone receptor (FSHR) mRNA expression. These results suggest that the testicular nerve supply plays an important role in supporting seminiferous tubule development and spermatogenesis from prepuberty to adulthood.