Effects of bilateral efferent duct ligation on sperm motility and secretion of FSH, LH, inhibin, and testosterone in adult male rats

Effects of bilateral efferent duct ligation (EDL) on sperm motility and testicular endocrinology were investigated in adult male rats. Bilateral EDL was created surgically in adult male rats (EDL group) and sham-operated rats were used as control (control group). Five rats from each group were killed on d 3, 5, 7,14, and 35 after the surgery. The sperm motility parameters were determined by a computer-assisted sperm analysis system using sperm collected from the cauda epididymis. Concentrations of spermatozoa in epididymis and testis were counted. The motility of sperm decreased remarkably in EDL rats compared with controls on 5 d after the operation. Four sperm motility parameters-straight velocity (VSL), deviation of the sperm head from the mean trajectory (ALH, mean), the maximum amplitude of lateral head displacement (ALH, max) and curvilinear velocity (VCL)-increased on 3 d after the operation, and followed by a subsequent decline 5 and 7 d later. Concentrations of sperm significantly decreased in both testes and epididymis from 3 and 5 d after the operation. Plasma concentrations of FSH and LH increased significantly in EDL rats from 5 and 7 d after the operation, whereas plasma concentrations of immunoreactive (ir)-inhibin, inhibin B, and testosterone decreased. Testicular content of inhibin showed an initial increase on 3 d after the operation, followed by a subsequent decline to levels significantly below controls by d 7 postoperation. On the other hand, testicular contents of testosterone were significantly higher in the EDL group than the control group on d 7-35 after the operation, whereas circulating levels of testosterone remained low. In the EDL testes, marked degenerative changes in the Sertoli cells and spermatogonia were observed, whereas Leydig cells showed clear hyperplasia. These results demonstrated that bilateral EDL induced a rapid reduction of sperm motility parameters during a short time. Present results also suggest that EDL first induces impairment of Sertoli cells function and this leads to reduction of sperm activity and secretion of inhibins. On the other hand, circulating levels of testosterone reduced after EDL and this leads to hypersecretion of LH. A large amount of LH resulted in a stimulation of Leydig cells hyperplasia.