Abstract: Objective To study the toxic effect and its mechanism of apoptosis induced by nickel sulfate in ovarian cells of female mice,and to offer scientific basis for preventing and curing premature ovarian failure(POF).Methods Healthy female Kunming mice were injected intraperitoneally with different doses of nickel sulfate(10.0,5.0,2.5 mg/kg)continuously for 12 days.Vaginal smears of mice were taken to determine estrous cycle.Morphological changes of apoptotic cells were observed by light microscopy,and the cell cycle and DNA content were analyzed by flow cytometry(FCM).Results (1)The dioestrus was prolonged and irregular in toxicant exposure groups.(2)By light microscopy,there were many morphological characteristics of apoptosis including compaction and margination of nuclear chromatin,nuclear fragments,and apoptotic bodies.(3)The result of FCM showed that nickel sulfate could result in the the arrest of G₀/G₁ phase and reduce the percentage of G₂/M、S phase.The percentage of apoptosis and D.I was also increased while PI was reduced.Conclusion Intraperitoneal-injected nickel sulfate could induce the lesion of mice's ovary.