Effect of Lindera Aggregata Extract on Lipid-lowering and Hepatic LKB1-AMPK Pathway in Hyperlipidemic Rat Model

OBJECTIVE To study the antilipemic function of extract from Lindera aggregata and the effect on hepatic LKB1-AMPK pathway in hyperlipidemia model rats. METHODS A rat model of mixed hyperlipidemia induced by high-fat diet, high and low doses group were administered with high and low doses of 1.6, 0.8 g·kg^-1 of crude drug extracts for 8 weeks. The positive group was administered with 20 mg·kg^-1 fenofibrate. Serum levels of total cholesterol(TC), triglyceride(TG), low-density lipoprotein cholesterol(LDL-C), high-density lipoprotein cholesterol(HDL-C) were detected after 4 and 8 weeks administration. At the end of the experiment, the rats were sacrificed and the liver was dissected to observe its effect on liver index and the degree of lipid accumulation in liver tissues was observed by oil red O staining. Western blotting was used to detect the expression of LKB1-AMPK pathway related proteins in liver. RESULTS After continuous administration for 4 weeks, compared with the model group, the levels of TG in serum significantly reduced in the positive group(P<0.05). After continuous administration for 8 weeks, the high dose group significantly reduced the levels of TC and LDL-C in serum compared with the model group(P<0.01 or P<0.05). Compared with the control group, the liver index of the high and low dose groups and the model group were extremely significantly increased(P<0.01). Compared with the model group, the high and low dose groups had a decreasing trend, but there was no statistical difference. The results of oil red O staining in liver tissue showed that the hepatocytes in the model group had serious lipid accumulation and high degree of steatosis, and the hepatocytes in the high dose group of Lindera aggregata extract had different degrees of improvement in lipid accumulation and steatosis. The high and low dose group, AMPKα protein phosphorylation was significantly increased in rats liver. CONCLUSION Lindera aggregata extract has certain lipid-lowering effect and can improve hepatocyte steatosis. The mechanism may promote lipid metabolism by activating AMPKα protein phosphorylation.