Sildenafil citrate is a potent and selective inhibitor of cGMP-specific phosphodiesterase type 5 enzymes (PDE5I).it is one of the most common drugs used to treat erectile dysfunction in men. It catalyzes the breakdown of cGMP, one of the primary factors involved in smooth muscle relaxation. A complex cross-talk phenomenon between the cAMP- and the cGMP- generating systems regulating the sperm function occurs in human spermatozoa. This study was thus designed to investigate the role of sildenafil in a model of colchicine induced infertility. Three groups of rats were employed in this study; group 1 served as control.In group 2 rats were treated with colchicine 25 mg/kg/days subcutaneous (s.c.) once daily for 25 successive days. Group 3 (Sildenafil citrate- treated group) was treated as group II and this was done coincidently with oral treatment with sildenafil citrate (8mg/kg) by oral gavage daily orally for the same 25 days. Testicular blood flow (TBF) was estimated by flowmeter. Seminal parameters (progressive motility, sperm cell concentration, epididymal sperm abnormal forms) were estimated. Male sexual behaviour was also evaluated (mounting, intromission, ejaculation, mount and intromission latencies, mount and intromission frequencies, ejaculatory latency, ejaculation frequency and intercopulatery interval).Testicular tissue specimens were histopatholgically examined by hematoxylin & eosin staining. Colchicine administration for 25 days resulted in marked impairment of TBF & seminal parameters and sexual behaviour .All these factors were significantly improved by sildenafil. These results clearly demonstrate the pivotal role of sildenafil in colchicine induced infertility. |
