Mechanism of Zhishi Xiebai Guizhitang in Treating AS Based on Regulation of Cholesterol Metabolism in Foam Cells by TRPA1 / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo explore the effect and mechanism of Zhishi Xiebai Guizhitang on the progression of atherosclerosis （AS） mice based on the regulation of cholesterol metabolism in foam cells by transient receptor potential channel ankyrin 1 （TRPA1）. MethodThe AS model was established on apolipoprotein E knockout （ApoE-/-） mice with a high-fat diet. The mice were randomly divided into low-dose， middle-dose， and high-dose groups of Zhishi Xiebai Guizhitang （2.97， 5.94， 11.88 g·kg-1） and simvastatin group （0.002 g·kg-1）， and the drug was administered along with a high-fat diet. C57BL/6J mice were fed an ordinary diet as a normal group. After the above process， the aorta and serum of mice were taken. The pathological changes of the aortic root were observed by hematoxylin-eosin （HE） staining. The lipid plaques in the aorta were observed by gross oil redness. Serum levels of total cholesterol （TC）， triglyceride （TG）， low density lipoprotein cholesterol （LDL-C）， and high density lipoprotein cholesterol （HDL-C） were detected， and the levels of interleukin-1β （IL-1β） and interleukin-18 （IL-18） were detected by enzyme-linked immunosorbent assay （ELISA）. Western blot and immunohistochemical method were used to analyze the expression of TRPA1， ATP-binding cassette transporter A1 （ABCA1）， ATP-binding cassette transporter G1 （ABCG1）， and mannose receptor （CD206）. ResultFrom the perspective of drug efficacy， compared with the normal group， pathological changes such as plaque， a large number of foam cells， and cholesterol crystals appeared in the aorta of the model group， and the serum levels of TC， LDL-C， IL-1β， and IL-18 were significantly increased （P<0.01）. The HDL-C level was significantly decreased （P<0.01）， and the CD206 level in aortic tissue was significantly decreased （P<0.01）. Compared with the model group， the lipid deposition in the aorta was alleviated in all drug administration groups. In addition， except for the high-dose group of Zhishi Xiebai Guizhitang， all drug administration groups could significantly decrease the levels of TC and LDL-C （P<0.01）. In terms of inflammation， except for the middle-dose group of Zhishi Xiebai Guizhitang， the levels of IL-1β and IL-18 were significantly decreased in all drug administration groups （P<0.05）. Moreover， Zhishi Xiebai Guizhitang could also up-regulate the levels of CD206， and the difference was significant in the middle-dose and high-dose groups （P<0.05）. From the perspective of mechanism， the expression levels of TRPA1， ABCA1， and ABCG1 in the aorta in the model group were lower than those in the normal group （P<0.05）. Compared with the model group， all drug administration groups significantly increased the expression of TRPA1 in the aorta （P<0.05）， and the expressions of ABCA1 and ABCG1 were increased. The differences in the middle-dose and high-dose groups and the simvastatin group were significant （P<0.05）， which was basically consistent with the trend of immunohistochemical results. ConclusionZhishi Xiebai Guizhitang can effectively reduce blood lipid and inflammation levels and inhibit the formation of aortic plaque. The mechanism may be explained as follows： the expressions of ABCA1 and ABCG1 downstream are increased through TRPA1， which promotes cholesterol outflow in foam cells， thereby regulating cholesterol metabolism， intervening in inflammation level to a certain extent， and finally treating AS.