Abstract: AIM: To study the toxic effects of HU on reproductive system in male rats.METHOD: By intrap-eritoneal injection,HU were administrated to male Wistarrats at different doses of (100,200,and 400 mg·kg^-1)once a day for10 days,and the rats were randomly sacri-ficed on the 9th and twentieth-third days afterwithdrawal of HU,respectively.RESULTS: Inactive sperm in 200 and 400 mg·kg^-1 grouPwas higherthan that in the con-trol grouPon the 9th afterwithdrawal.On the twentieth-third afterwithdrawal,the testis body ratios,three treat-ment groups were decreased significantly than that in the control grouP(P<0.05,orP<0.01) ,the epididy-mides body ratios was decreased significantly in 400 mg·kg^-1 group,and inactive sperm remains had de-creased significantly (P<0.01) ,200,400 mg·kg^-1 groups of the numberof sperm had decreased significantly than that in the control grouP(P<0.01).In the groups treated,the rates of sperm deformity were signifi-cantly higherthan that of the control,and the higherthe expose concentration of HU,the higherthe rate of sperm deformity on the 9th and the twentieth-third (P<0.01).CONCLUSION: HU can result in the obviously adverse effects on the reproductive system of male rats,its aim organs may be testis and epididymis,and affect the course of spermatogenesis.Afterwithdrawal,these dam-ages are hard to recoverand still development within a certain time.

Key words: HU, male, reproductive toxicity, rats, sperm