ABSTRACT
Objective This study aims to investigate the effects of high-fat diet rich in perilla oil on the insulin sensitivity-related gene expression in skeletal muscle in insulin resistant rats.Methods The insulin resistant ( IR) rat models were randomly divided into 2 groups, including high fat group ( HF) and perilla oil ( PO) intervention group fed with 20%substitution of lard energy in the HF.The insulin sensitivity of rats was measured after 4 weeks.Theα-linolenic acid ( ALA) content of PO in the rat plasma were analyzed by gas chromatograph.Real-time PCR was applied to measure glucose transporter 4 ( GLUT4 ) and insulin receptor substrate-1 ( IRS-1 ) mRNA, and Western blot assay was used for detecting the expression of GLUT4 and IRS-1 in the skeletal muscle.Results At the gene and protein levels, PO remarkably reduced the level of IRS-1 and upregulated the level of GLUT4 with increasing intake of ALA and serum ALA content in IR rats.The results of hyperinsulinemic-euglycemic clamp test showed no significant difference between the two groups.Conclusions The results of our study suggest that consumption of n-3 PUFA at levels that can typically be found in the diet fed to IR rats in the form of ALA (0.556 g/d) may not improve insulin sensitivity, even though regulating the expression of GLUT4 and IRS-1 in the skeletal muscle.
ABSTRACT
Objective This study aims to investigate the effects of high-fat diet rich in perilla oil on the expression of key genes that regulate hepatic VLDL synthesis in obese rats .Methods Sixty healthy male 5-week old SD rats were randomly divided into 2 groups.The rats in the normal control group (NC, n=12) were given normal diet, and the rats in the high fat group ( HF, n=48) were given a pure high fat diet in order to induce rat models of obesity .In the intervention period, the obesity model rats were randomly divided into 4 subgroups including consistent high fat group (CHF) and three intervention groups depending on perilla oil substitution rate of lard in CHF:20%PO, 50%PO and 100%PO.The serum triglyceride (TG) of the rats was measured after 4 weeks.Real-time PCR was applied to measure microsomal triglyceride transfer protein ( Mtp) and apolipoprotein B ( Apob) mRNA, and western blot assay was used for detecting the expression of MTP and APOB in the liver .Results Compared with the NC group , the CHF rats exhibited significantly high fat deposi-tion.The serum TG was markedly higher and the MTP and APOB were decreased at gene and protein levels in the CHF group compared with the NC group .After the intervention , PO remarkably reduced the level of serum TG and decreased he-patic fat deposition as it showed by pathological examination .At the gene and protein levels , MTP and APOB were upregu-lated by PO to different degrees .Conclusions All the three PO intervention can promote VLDL synthesis and secretion , and decrease the hepatic fat deposition in the obese rats .Furthermore , PO upregulates the expression of MTP at gene and protein levels in a dose-dependent manner .