SU Dehui, SU Huina, TAN Cheng, LIU Yanhua, JIANG Xiaolin, SUN Xiaowan, ZHANG Mengyu, LEI Tonghao, MA Ruiqiong, YANG Xin.
Objective To compare ovarian function changes and the mechanisms of aging and apoptosis in mouse models of premature ovarian failure (POF) induced by different doses of cyclophosphamide (CTX), and to identify the optimal modeling method. Methods Thirty female C57BL/6 mice aged 6~8 weeks were randomly divided into six groups: the Control group, POF1 group 120 mg/kg, POF2 group 200 mg/kg, POF3 group 50 mg/kg×14 days, POF4 group 400 mg/kg, and POF5 group 25 mg/kg×14 days. The mice received intraperitoneal injections of cyclophosphamide (CTX), respectively. The ovarian function, as well as changes in senescence and apoptosis, were recorded and compared under different CTX doses and administration frequencies in the POF mouse models. Results Compared to the control group, all model groups exhibited disrupted estrous cycles, reduced sex hormone expression, increased ovarian fibrosis, and a decrease in follicle count (P<0.05). The expressions of anti-Müllerian hormone (AMH) and follicle-stimulating hormone receptor (FSHR) were significantly reduced (P<0.05), and the severity of ovarian damage was positively correlated with CTX dose (|r|>0.500, P<0.05). Additionally, all model groups showed increased cellular senescence and apoptosis. In the POF1, POF2, and POF5 groups, the expressions of senescence-related molecules such as cyclin-dependent kinase inhibitor 2A (p16), cyclin-dependent kinase inhibitor 1A (p21), and senescence-associated β-galactosidase (β-gal) were significantly higher than those in the POF3 group (P<0.05). Conversely, in the POF3 group, apoptosis-related molecules such as Bcl-2-associated X protein (Bax), cysteine-aspartic acid protease 3 (Caspase3), and phosphorylated H2A histone family member X (γ-H2AX) were significantly more highly expressed than in the POF2 and POF5 groups (P<0.05). Conclusions CTX at different doses can induce POF in mice, with the severity of ovarian damage increasing in a dose-dependent manner. Lower doses of CTX primarily cause ovarian damage through cellular senescence mechanisms, while higher doses primarily induce ovarian damage through apoptosis.