Coenzyme Q10 ameliorates obesity by promoting white adipose tissue browning and preserving mitochondrial dynamics in ovariectomized rats fed a high-fat diet

Estrogen deficiency caused by menopause leads to obesity in women. In obesity, excessive visceral fat accumulation induces a chronic, low-grade inflammatory response, thereby increasing the risk of cardiovascular disease, insulin resistance, and type 2 diabetes mellitus. Browning of white adipose tissue (WAT) has emerged as a promising strategy to counteract obesity and related metabolic disorders. Coenzyme Q10 (CoQ10) has been reported to reduce oxidative stress, enhance mitochondria function and improve metabolic syndrome in obese and diabetic animals and patients. In this study, we evaluated whether long-term CoQ10 supplementation could induce WAT browning to ameliorate obesity in ovariectomized (OVX) rats fed a high-fat diet (HFD), and explored the underlying mechanisms. Supplementation with CoQ10 (20 and 40 mg/kg, once daily by gavage) for 12 weeks in OVX rats significantly reduced weight gain, excessive visceral fat accumulation, white adipocyte hypertrophy, plasma triglyceride levels, and glucose intolerance, while increasing energy expenditure compared to OVX rats treated with vehicle (P<.05). High dose CoQ10 (40 mg/kg) significantly lowered plasma insulin levels, reduced HIF-1α, MCP-1 and IL-6 protein expression, and increased phosphorylated AKT in retroperitoneal WAT (P<.05). In inguinal WAT (iWAT), CoQ10 enhanced the expression of browning-related proteins including UCP-1, CIDEA, PRDM16, PGC-1α, and phosphorylated AMPK, and elevated plasma irisin levels (P<.05). CoQ10 also regulated mitochondria dynamics of iWAT, as evidenced by increased MFN1, MFN2, and OPA1, and decreased FIS1 protein expression compared with the OVX group (P<.05). In 3T3-L1 adipocytes, CoQ10-induced expression of browning markers (UCP-1, TBX1 and PRDM16) was significantly suppressed by dorsomorphin, an AMPK inhibitor, and by AMPK knockdown (P<.05). In conclusion, long-term CoQ10 supplementation ameliorates weight gain, white adipocyte hypertrophy and inflammation in WAT, and metabolic disorders caused by combined estrogen deficiency and HFD, likely through its WAT browning effect. AMPK activation is suggested to contribute to the browning effect and enhance the expression of proteins involved in mitochondrial dynamics. Therefore, CoQ10 supplementation could be an effective intervention for preventing postmenopausal obesity.