The effect of hyperprolactinemia on epididymal sperm motility in rats

Abstract

OBJECTIVE: Hyperprolactinemia (hyperPRL) is a pathological status that might interfere the reproductive function in both male and female mammals. This study is to investigate the effects of pathological levels of prolactin (PRL) on epididymal sperm motility in a hyperPRL rat model induced by pituitary glands allografting. DESIGN: Animal study. MATERIALS AND METHODS: Two anterior pituitary glands were grafted to the subrenal capsule of the recipient rats. Stable hyperPRL status was achieved 6 weeks after the surgery. The control rats were grafted with similar amount of cerebral cortical tissues. Totally 8 rats were assigned for each groups. The blood levels of PRL were measured by radioimmunoassay. Six weeks after grafting, the whole epididymis was removed and transferred to a tube containing 2 ml of Medium 199. The epididymis was cut into small pieces by scissors to release the sperm, and 8 ml of buffer was added to the tube. After mixing, 0.6 ml was transferred to a swim-up chamber and it was layered carefully with 6 ml of medium. The chamber was kept standing still for 2 hours at a 34C environment to allow the sperm to swim up. The samples from the top, middle and bottom part of the chamber were measured for count and motility. RESULTS: The over all sperm count showed relatively similar for both groups. The epididymal sperm motility was 11.9 ± 3.4 % for control groups and 4.0 ± 1.6 % for the hyperPRL rats (P< 0.001). The proportion of motile sperm at the top end of the swim-up chamber was also more abundant in the control group. CONCLUSIONS: We concluded from these results that hyperPRL might influence the motility of epididymal sperm. But we still could not be sure whether the detrimental effects are originated from the testis or the epididymis.