Expression of endothelial nitric oxide synthase in the Sertoli cells of men with infertility of various causes

Objective To investigate how endothelial nitric oxide (eNOS) expression in the seminiferous tubules might be related to spermatogenesis, by examining eNOS expression in testicular tissue of patients infertile from various causes, Patients and methods The study included five fertile men with a normal sperm concentration, nine patients with obstructive azoospermia, 20 with varicocele testes and eight with idiopathic azoospermia (Sertoli cell-only syndrome). Testicular biopsy specimens were examined by immunohistochemistry for eNOS protein expression, in addition to a routine pathological assessment, eNOS protein was detected using an eNOS monoclonal antibody. A Sertoli cell staining index (SST) was defined as the ratio of stained Sertoli cells per total number of Sertoli cells, and was compared among the groups. Results eNOS was localized to Sertoli cells in the seminiferous tubules and Leydig cells in the interstium; although some degenerating germ cells stained, normal germ cells did not. The SSI was significantly lower in patients with Sertoli cell-only syndrome than in either fertile men or patients with obstructive azoospermia or varicocele. However, the SSI did not correlate significantly with the Johnsen score. Conclusion The expression of eNOS in Sertoli cells may depend on the existence of germ cells and be associated with germ cell development.