Objective: The aim of this study was to investigate the effects of icariside Ⅱ(ICA Ⅱ)on the prevention of streptozotocin(STZ)induced spermatogenic dysfunction.Methods: Forty male Sprague-Dawley rats received intraperitoneal injection of STZ(55 mg/kg)and were equally randomized to gavage feeding of vehicle(the vehicle group)or ICAⅡ(0.5,1.5 or 4.5 mg/kg/day,respectively).Ten normal rats received vehicle and served as control.Four weeks later,sperm parameters,histopathological changes,testicular lipid peroxidation,antioxidant enzyme activities,and apoptosis index(AI)were evaluated.Results: Results showed that ICAⅡ treatment resulted in a significant recovery of sperm parameters and histopathological changes relative to the vehicle group(P<0.05).In the vehicle group,antioxidant enzyme activities and the expression of Sertoli cell Vimentin filaments obviously decreased,while lipid peroxidation and AI significantly increased as compared with the control group(P<0.05).Following ICAⅡ treatment,corrective effects on these items towards normal levels were observed.Conclusions: The results suggested that ICAⅡ has beneficial effect on the preservation of spermatogenic function in the STZ-induced diabetic rats.The mechanisms might be related to its improvement of antioxidant enzyme activities;preservation of the protein expression and apical extensions of Vimentin filaments,and anti-apoptosis capability.