Abstract: Objective: To study the antagonistic effect of oral contraceptives （OCs） on the tripterygium wilfordii polyglycoside （TWP）-induced gonad toxicity in the female SD rats. Methods：40 female SD rats were divided randomly into four groups：the TWP group，the OCs group，the TWP with OCs group，and the blank control group. Test of vaginal exfoliated cell smears was done everyday after 10 weeks′ treatment. Rats were sacrificed after stopping treatment 3 weeks. Serum follicle stimulating hormone （FSH），luteinizing hormone （LH），estradiol （E2） were measured by ABC-ELISA. The weights of uterus and ovaries，and the number of follicles，were compared among groups. The histomorphology of uterus and ovary was observed by microscope. Results：The oestrous cycle in the TWP group was incomplete or extended；serum E2 level [（40.417 4±4.937 2） ng/L] was significantly lower than those in other groups；while FSH level[（1.063 4±0.153 9） IU/L] and LH levels [（5.946 7±1.036 0） IU/L] were significantly higher than those in other groups （P＜0.01）. The weight indexes of uterus （0.048 7%±0.009 7%） and ovaries（0.147 0%±0.004 7%），and the thickness of endometrium [（57.20±1.81）μm] and myometrium [（24.40±1.84） μm]，were significantly lower than those in other groups （P＜0.01）. The numbers of growing follicle （22.50±2.55） and graaffian follicle （2.00±1.89） in the TWP group were significantly less than those in the other groups （P＜0.05），while there was not significant difference in the number of primordial follicles （36.50±2.64） in the TWP group when compared with other groups （P＞0.05）. Conclusions：Diane-35 can decrease the TWP-induced gonad damage in female SD rats，which plays a potential role in protecting ovarian function.

Key words: Tripterygium, Saponins, Contraceptives, oral, Gonads, Diane-35