Effects of Acute Hypoxic Exposure on Ovarian Function in Female Mice

To investigate the effects of acute high-altitude hypoxia on ovarian function and ovarian tissue transcriptomics in female mice, providing experimental evidence for elucidating the mechanisms underlying female reproductive damage caused by acute high-altitude hypoxia. Sixty female mice were randomized into three groups (20 mice each): control (CON, 500 m, conventional housing for 14 d), 7 d hypoxic exposure (LO1) and 14 d hypoxic exposure (LO2). LO1 and LO2 were kept in a low-pressure hypoxic chamber simulating 5500 m. Serum reproductive hormones (AMH, FSH, LH, E₂) and oxidative stress markers were detected; ovarian indices were calculated and ovarian histopathology examined. Additionally, transcriptome sequencing and functional enrichment analysis of differentially expressed genes were conducted on ovarian tissues. Compared with CON, LO1 and LO2 showed markedly decreased serum AMH, LH and E₂ (P < 0.01), sharply elevated FSH (P < 0.001), increased malondialdehyde (P < 0.001), reduced superoxide dismutase activity (P < 0.01), first increased then decreased total antioxidant capacity (P < 0.001), and lower ovarian index (P < 0.01). Histology showed ovarian atrophy and ischemic congestion, with fewer primary, secondary and mature follicles (P < 0.05) and more atretic follicles in LO2 (P < 0.05). Transcriptome sequencing found 234 significantly differentially expressed genes, whose co-differentially expressed ones were enriched in oxygen transport/oxidative stress and steroid hormone synthesis pathways. Acute high-altitude hypoxia impairs ovarian reserve function and disrupts follicular development in female mice, potentially through oxidative stress imbalance and dysregulation of genes involved in steroid hormone synthesis pathways.