Effect Of L-NAME On Spermatogenic Cell Apoptosis In Rats Experimental Orchidopexy

Objective: To investigate expression of eNOS ,iNOS and effect of L-NAME on spermatogenic cell apoptosis in rats experimental orchidopexy.Methods: Seventy-five immature male Sprague-Dawley rats(22day-old) were randomly divided into two groups: sham operation(15rats) and cryptorchid(60rats). Unilateral cryptorchidism was surgical-ly induced in the rats under pentobarbital anaesthesia:a midline abdominal incision was made and then the right testis was sutured to the abdominal wall after the gubernaculum was cut to prevent testis descent. The gubernaculums of the right testes in the sham operation group were cut before replaced into the scrotum. On the 12th day after operation, the cryptorchid rats were randomly devided into four groups: cryptorchid(The rats that did not undergo the surgery) , orchidopexy, orchidopexy + normal saline, orchidopexy + L-NAME. Unilateral orchidopexy was surgical-ly induced in the rats under pentobarbital anaesthesia:a midline abdominal and scrotum incision were made and then the right testis was unfixed from the abdominal wall and replace the testis into scrotum. The right testis in the sham operation group was replaced into the scrotum immediately after displaced from the scrotum to the abdomen. The rats of orchidopexy +normal saline group and orchidopexy +L-NAME group were injected intra -peritoneally normal saline and L-NAME(50mg/Kg) accordingly. The blood samples were collected from the tail after injection two hours on the 12th day.The serum were collected and stored at–80℃for subsequent detection. Serum NO concentration was measured by Greiss method . The activity of NOS in serum was measured by colorimetric method. The rats were sacrificed on the 24th day after the second operation. The morphology of spermatogenic epithelium in rats of every group was observed with light microscopy. The level of spermatogenic cell apoptosis in the unilateral cryptorchidism and orchidopexy rats were evaluated by FCM and TUNEL.The protein expression level of eNOS and iNOS in testes were detected by Western blot and immunohistochemical assay accordingly.Results: The level of spermatogenic cell apoptosis, serum NO concentration and the activity of NOS in rats cryptorchidism were higher than the rats orchidopexy but the weight of testes were lighter than the rats orchidopexy. Administration of L-NAME could decrease serum NO concentration and spermatogenic cell apoptosis in rats experimental orchidopexy, and it could significantly inhibit weight lose of the orchidopexied testes. The activity of NOS was attenuated significantly by L-NAME. The protein expression level of eNOS and iNOS in the testes of the sham operation group was the lowest in the four groups. The expression of eNOS and iNOS in the spermatogenic epithelium were feeble in the sham operation group but strong in other three groups by immunohistochemical assay. Conclusions: 1. The improvement of spermatogenesis is relate to the reduction of spermatogenic cell apoptosis in rats experimental orchidopexy.2. NO is the important biology active gene of excess apoptosis in spermatogenic cell in rats experimental orchidopexy.3. L-NAME can reduce the production of NO and spermatogenic cell apoptosis,it shows that the inhibitor of NOS can promote the enhancement of spermatogenic capability in rats experimental orchidopexy.