Estrogen deficiency in postmenopausal women is linked to the higher prevalence of obesity, type 2 diabetes and metabolic syndromes. Development of beige adipocytes (browning of WAT) increases energy expenditure and could be a promising strategy for obesity management. This study aimed to investigate the effects of phytoestrogen genistein (GEN) on white adipose tissue (WAT) inflammation, browning and hepatic lipogenesis in ovariectomized rats with high-fat diet (HFD) and further explore the underlying mechanism. Female Wistar rats received ovariectomy (Ovx) and HFD (45% fat) and then were administered with 17β-estradiol (E2, 3 times/week, subcutaneously) or GEN (15 mg/kg or 30 mg/kg, gavage, once daily) for 4 weeks. Administration of GEN decreased Ovx-induced body weight gain and adiposity and improved insulin sensitivity as well as increased insulin signaling p-IRS1 and p-AKT in retroperitoneal WAT. Adipocyte hypertrophy and production of proinflammatory cytokines MCP-1, TNF-α and IL-6 were reduced by GEN. It also suppressed the activation of NF-κB pathway evidenced by attenuation of p65 and phospho-IκB levels. Additionally, GEN elevated myokine irisin and promoted WAT browning by increasing UCP-1, PRDM-16, PGC-1α and CIDEA proteins and Ppargc1a, Ucp-1 and Tbx-1 mRNA in inguinal WAT which is associated with up-regulation of nuclear estrogen receptor-α. Plasma levels of triglyceride and cholesterol were reduced by GEN treatment accompanied with inhibition of lipogenic proteins (p-ACC, SREBP-1, FAS and CD36) in the liver. Long-term treatment with GEN attenuated estrogen-deficiency-induced obesity, WAT inflammation and hepatic lipogenesis and promoted the induction of WAT browning. It may provide a promising approach to prevent obesity during menopause.
Keywords: Adipose tissue browning; Hepatic lipogenesis; Inflammation; Menopause; Obesity.
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