Mechanisms of Cell Senescence and Apoptosis in Cyclophosphamide-Induced Premature Ovarian Failure in Rats

Background Premature ovarian failure (POF) is a clinical condition characterized by a diminished ovarian reserve occurring before the age of 40, significantly affecting female reproductive health. However, its exact pathogenesis remains unclear. This research aimed to examine the mechanisms of cyclophosphamide (CTX)-induced senescence and apoptosis in the ovarian and cerebral cortex tissues of rats to provide insights into delaying aging and protecting female reproductive health. Methods A POF rat model was established via intraperitoneal injection of CTX, with the modeling effect confirmed by measuring ovarian volume and weight. Serum changes were detected using enzyme-linked immunosorbent assay (ELISA). Senescence-associated β-galactosidase (SA-β-gal) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining were performed to assess brain cortex and ovarian tissues. Western blotting and quantitative polymerase chain reaction (RT-qPCR) were used to detect the expression levels of proteins and genes related to cellular senescence and apoptosis, validating the correlation between POF, cellular senescence, and apoptosis. Results High-dose CTX induced POF. In rats with POF, the levels of anti-Müllerian hormone (AMH), estradiol (E2), and vitamin D (VD) significantly decreased ( P < 0.0001 ), whereas the levels of testosterone (T) and insulin (INS) significantly increased ( P < 0.0001 ). The number of senescent and apoptotic-positive cells in the ovarian and cerebral cortex tissues of rats with POF was substantially augmented ( P < 0.05; P < 0.01 ). Additionally, the expression of senescence-related proteins cyclin-dependent kinase inhibitor 1A (CDKN1A), cyclin-dependent kinase inhibitor 2A (CDKN2A), tumor protein p53 (P53), apoptosis-related protein BCL2-Associated X Protein (Bax), and cysteine-aspartic acid protease 3 (caspase 3) was upregulated. In contrast, the expression of the anti-apoptotic protein BCL-2 was downregulated. These findings demonstrated that high-dose CTX injection leads to cellular senescence and apoptosis, resulting in ovarian pathology. Conclusion High-dose CTX induced POF in rats, resulting in aging and apoptosis in the cerebral cortex and ovarian tissues. Therefore, inhibiting cellular senescence and apoptosis may be a potential approach for restoring ovarian reserve function in POF.