Soy Isoflavone and Its Effect to Regulate Hypothalamus and Peripheral Orexigenic Gene Expression in Ovariectomized Rats Fed on A High-Fat Diet

摘要

Objective To explore the effect of soy isoflavone on obesity in the light of hypothalamus and peripheral orexigenic gene regulation.Methods Fifty-four female rats were randomly assigned to 6 groups:one sham-operated group (SHAM),one ovariectomized (OVX)control group,three OVX groups fed with 400 ppm(L-SI),1 200 ppm(M-SI)and 3 600 ppm(H-SI)isoflavone respectively,and one OVX group receiving 0.45 ppm diethylstilbestrol(EC).All rats were allowed to take high-fat diet for 4 weeks.Some neuropeptides were measured by RT-PCR.These neuropeptides included NPY,pro-opiomelanocortin(POMC),cocaine and amphetamine regulated transcript(CART),orexin,melanin-concentrating hormone(MCH),melanin-concentrating hormone precursor(P-MCH),ghrelin,and leptin.Results Compared with the OVX control group,the body weight and food intake in the H-SI group were reduced significantly and there was a significant dose-dependent manner in the 3 isoflavone groups.The results of RT-PCR showed that the NPY level in the 3 isoflavone groups was significantly increased and the POMC/CART gene expression decreased significantly in rats' hypothalamus compared with that in the OVX control group.However,the expression of orexin,MCH and P-MCH had no change.The peripheral grelin mRNA expression was higher in the 3 isoflavone groups,while leptin gene expression in the fat was not consistent.Conclusions This research showed that isoflavone could prevent obesity induced by high-fat diet and ovariectomy through regulating hypothalamus and peripheral orexigenic gene expressions associated with food intake.