Study on the curative effect and the protection mechanism of Paeoniflorin on nonalcoholic fatty liver rats

Objective:To discuss the effect of Paeoniflorin on insulin resistance rats induced by high fat diet and explore the mechanism of its protection.Methods:62 healthy male rats were randomly divided into control group(NC group)(n=11) and high-fat group(n=51),respectively fed with normal chow and high fat diet.The high-fat group was divided into five groups:the PE200-treated group(n=10),the PE100-treated group(n=10),the PE50-treated group(n=10),the Bicyclol-treated group(n=10),and the model group(n=10).After ten weeks,the animals in the PE200-treated group,the PE100-treated group and the PE50-treated group were orally administered paeonia abra(PE)(200,100 and 50mg·kg-1·d-1) for 4 weeks.The animals in the Bicyclol-treated group were orally administered Bicyclol(100mg·kg-1·d-1) for four weeks,and the model group was treated with distilled water.Rats in each group were kept for 14 weeks before killed.Adipose tissue around kidney and epididymis were dissected.And the FBG,FINS,IRI,ISI were measured.The weight of adipose tissue and body were measured.And serum adiponectin(APN) level was detected by ELISA.Liver histology was detected by HE staining and Oil-red O staining.The gene expressions of Phosphorylation of AMP-activated kinase(AMPK),and two key lipogenesis regulators of SREBP-1 c and FAS were detected by RT-PCR.Results:Insulin resistance rats were induced by high-fat diet for 10 weeks successfully.After 14 weeks feeding,the rats in model group showed obvious visceral obesity.Compared with NC group,adipocyte size significantly increased in model group(P0.05,P0.01).However,insulin sensitivity and serum APN level in model group were much lower than those of NC group(P0.01).Compared with model group,the insulin sensitivity as well as serum APN level of rats in the four treated groups had obviously improved(P0.05,P0.01).Phosphorylation of AMPK levels in model group decreased with the regulation of SREBP-1c and FAS gene high expressions(P0.05,P0.01),but phosphorylation of AMPK levels increased and the expressions of SREBP-1c and FAS gene decreased by peony extract treatment for four weeks(P0.05,P0.01).Conclusion:Peony extract administration significantly improved insulin resistance induced by high fat diet,and the mechanism might be related to the improvement of the visceral obesity and up-regulation of the serum APN level.