Study on the Role of the AMPK/PGC-1α Pathway in Cold-Induced Vascular Endothelial Cell Apoptosis and Uterine Damage

Cold exposure may influence reproductive health through vascular changes, yet its mechanisms remain underexplored. This study aimed to investigate the impact of cold exposure on uterine blood vessels and the expression of the AMPK/PGC-1α gene and protein in adult female SD rats. A primary dysmenorrhea model was established in female Sprague Dawley rats and subjected to continuous cold exposure. Changes in body weight, ear temperature, and estrous cycle were observed. Superoxide dismutase (SOD) activity and adenosine triphosphate (ATP) levels were measured to assess oxidative stress. Uterine tissue morphology was assessed via small animal ultrasound, microcirculation observed using RFLSI imaging, and vascular morphology along with caspase-3 and AMPK expression evaluated histologically and immunohistochemically. CD31 and TUNEL double immunofluorescence were used to assess vascular endothelial apoptosis levels. Western blot was used to analyze Bax, BCL-2, and pAMPK/AMPK expression levels. In vitro injury models were used to treat human umbilical vein endothelial cells (HUVECs) with cold stimulus using the AMPK inhibitor Compound C. RT-PCR quantified Bax, AMPK, p53, and PGC-1α expression. Hypothermia-exposed rats exhibited significantly reduced body weight and ear temperature (p < 0.05), prolonged estrous cycle (p < 0.01), and decreased uterine index (p < 0.01), accompanied by reduced SOD and ATP levels (p < 0.01, p < 0.05). Ultrasound and flow imaging revealed decreased uterine blood flow velocity in the hypothermia group (p < 0.01). Histomorphology revealed disorganized uterine cell arrangement, reduced uterine vessel count (p < 0.01), and increased mean vessel area (p < 0.01) in cold-exposed uteri. Immunofluorescence detection revealed increased vascular endothelial cell apoptosis (p < 0.05). Western blot results showed that proapoptotic protein Bax was upregulated (p < 0.01), Bcl-2 was downregulated (p < 0.05), p-AMPK and p-AMPK/AMPK ratio were elevated (p < 0.01) after cold exposure; Rt-qPCR results indicated that Bax and P53 mRNA were increased (p < 0.01), while PGC-1α expression was elevated (p < 0.01). Rt-qPCR results showed elevated Bax and p53 mRNA (p < 0.01), along with increased AMPK and PGC-1α expression (p < 0.01) in the cold-exposed group. In human umbilical vein endothelial cells (HUVECs), compound C attenuated cold-induced effects (p < 0.01) and downregulated Bax and AMPK expression (p < 0.01). Cold exposure exacerbates uterine oxidative stress and energy imbalance, disrupts microcirculatory homeostasis, and induces endothelial cell apoptosis. Excessive phosphorylation of AMPK may co-activate PGC-1α, jointly contributing to cold-induced uterine dysfunction and exacerbated dysmenorrhea. This study reveals potential signaling pathways underlying cold-induced uterine vascular abnormalities, providing novel theoretical foundations and targeted intervention strategies for the prevention and treatment of primary dysmenorrhea.