Relationship Between Hyperlipidemic Development Of Rabbits And INSIG-2 Gene Expression And Modulative Effect Of Berberine On It

ObjectiveTo investigate the effects of berberine (Ber) on lipid metabolism in rabbits with hyperlipidemia and its possible mechanism involved in the Insulin-induced gene 2 gene expression.Methods32 male New Zealand white rabbits were fed with high fat diet for 8 weeks, and then were randomly divided into four groups with or without pretreatment of drugs once a day for another 8 weeks: high-fat diet + solvent (HFD) ; high-fat diet + either fenofibrate (FD) or Ber low dose (BLD) , Ber high dose (BHD), and normal diet + solvent (ND) . The levels of TC,TG,LDL-C,HDL-C,LP(a) in blood , the activities of LPL and HL, the pathomorphology of hepatic tissue, and the mRNA expressions of Insig-2 and VDR of fat tissue as well as LDLR of liver by real time RT-PCR were detected 8 weeks after rabbits were treated with drugs.ResultsIt was obvious that the high fat diet significantly induced rabbits to develop hyperlidemia with increasing VDR and Insig-2 gene mRNA expressions from fat tissue of rabbits and reducing the LDLR gene mRNA expression in liver tissue, compared with normal diet. The intervention of berberine (Ber) not only significantly decreased serum levels of TC, TG , LDL-C, LP(a) and the activities of LPL and HL but also blunted the degree of hepatic fatty degeneration caused by high fat diet. The result of real time PCR demonstrated that the mRNA expressions of VDR and Insig-2 gene in fat tissue and LDLR gene in liver were significantly up-regulated by Ber. The effects of Ber with low dose were better than that of high dose.ConclusionsBer can significantly decrease the levels of blood-lipids of the hyperlipidemic rabbits, the mechanism of which may be related to elevating expressions of VDR and Insig-2 gene. As a result, the LDLR gene expression is up-regulated.