Isoflavones from Sojae Semen Praeparatum Regulate Lipid Metabolism in Atherosclerotic Mice Through PPARγ/LXRα/ABCA1 Signaling Pathway / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo study the effect of isoflavones from Sojae Semen Praeparatum （ISSP） on lipid metabolism in atherosclerotic mice， and decipher the underlying mechanism via the peroxisome proliferator-activated receptor gamma/liver X receptor alpha/ATP-binding cassette transporter A1 （PPARγ/LXRα/ABCA1） signaling pathway. MethodFifty ApoE-/- mice were randomly assigned into the model group， western medicine （atorvastatin calcium， 3.03 mg·kg-1） group， and low-， medium-， and high-dose ISSP （2.5， 5， 10 mg·kg-1， respectively） groups， with 10 rats in each group. Atherosclerosis model mice were established by bilateral ovariectomy and feeding high-fat diet. Another 10 ApoE-/- mice receiving ovariectomy and high-fat diet were taken as the sham group. Some mice died of postoperative infection， and finally 6 mice were included in each group. One week after operation， each group was administrated with corresponding drugs or equivalent amount of normal saline. After 12 weeks， the levels of triglyceride （TG）， total cholesterol （TC）， high-density lipoprotein cholesterol （HDL-C）， low-density lipoprotein cholesterol （LDL-C）， and non-esterified fatty acids （NEFAs） in serum and liver tissue were measured. The levels of tumor necrosis factor-α （TNF-α） and interleukin-6 （IL-6） in serum were detected by enzyme-linked immunosorbent assay （ELISA）. Hematoxylin-eosin （HE） staining and oil red O staining were used for observation of aortic plaque formation and liver lipid deposition. The mRNA and protein levels of PPARγ， LXRα， ABCA1， and ATP-binding cassette transporter G1 （ABCG1） in liver were determined by real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot. ResultCompared with the sham group， the modeling of atherosclerosis increased the aortic plaque area （P<0.01）， elevated the serum TC， TG， LDL-C， TNF-α， and IL-6 levels （P<0.01）， decreased the level of HDL-C （P<0.01）， increased the liver index （P<0.05） and the levels of TC， TG， and NEFAs in liver （P<0.01）， and caused obvious hepatic fat vacuoles and lipid deposition. In addition， the modeling down-regulated the mRNA levels of PPARγ， LXRα， ABCA1 in liver （P<0.05， P<0.01），and regulated the mRNA and protein levels of ABCG1（P<0.05， P<0.01）. Compared with the model group， atorvastatin calcium and middle-， high-dose ISSP reduced the serum TC， TG， LDL-C， TNF-α， and IL-6 levels （P<0.01）， decreased the liver index （P<0.01）， alleviated the liver fat vacuoles and lipid deposition， and increased the levels of TC， TG， and NEFAs in the liver （P<0.05， P<0.01）. Furthermore， they up-regulated the mRNA and protein levels of PPARγ， LXRα， ABCA1， and ABCG1 in the liver （P<0.05， P<0.01）. ConclusionISSP may regulate lipid metabolism through PPARγ/LXRα/ABCA1 signaling pathway to down-regulate the expression of inflammatory cytokines in serum and alleviate liver lipid deposition， thereby suppressing the formation of atherosclerotic plaque.