The hypolipidemic and anti-atherosclerotic effects of acacetin and its mechanism of action in mice / 药学学报

ABSTRACT

The purpose of this research is to investigate the effects of acacetin on serum lipid metabolism and atherosclerosis in mice and explore its molecular mechanism. HepG2 cells were treated with different concentrations of acacetin. The expression of LDL receptor (LDLR) and sterol-regulatory element binding protein-2 (SREBP-2) were detected by RT-qPCR and/or Western blot. C57BL/6J mice were given acacetin (50 mg·kg-1) for 5 weeks by gavage. Serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglyceride (TG) were analyzed by an automatic biochemical analyzer. The expression of LDLR or SREBP-2 was detected by Western blot. After 12 weeks of intragastric administration of acacetin (30 mg·kg-1) in apolipoprotein E knockout (ApoE KO) mice, the serum lipid levels were determined by an automatic biochemical analyzer. The lipid deposition in aortic plaque (en face) and aortic root plaque were stained with oil red O. The expression of LDLR and SREBP-2 were detected by RT-qPCR and/or Western blot. The intestinal content microflora was analyzed by 16S rDNA sequencing (All animal studies were approved by the Animal Experimentation Ethics Committee of Institute of Medicinal Biotechnology, CAMS & PUMC). In vitro results indicated that acacetin significantly up-regulated LDLR mRNA and protein levels, and stimulated LDLR transcription factor SREBP-2 protein expression. As indicated from in vivo studies, compared with control group, acacetin significantly decreased the serum levels of TC and LDL-C in C57BL/6J mice by 34% and 57% (P<0.01), respectively. Furthermore, mechanic study showed that acacetin significantly increased the protein expression of hepatic LDLR and SREBP-2. Although the results of serum lipid profiles, hepatic LDLR/SREBP-2 expression and area of atherosclerotic lesions in aorta and aortic root in ApoE KO mice showed differences between acacetin and high-fat diet group, the differences did not reach statistical significance. Nevertheless, acacetin exhibited a profound influence on the composition of the intestinal microbiota as indicated by 16s rDNA sequencing analysis. In conclusion, these results demonstrated that acacetin can decrease the serum lipid levels in C57BL/6J mice through up-regulation of hepatic LDLR and SREBP-2, and alter gut microflora in high-fat diet fed Apo KO mice. This study suggests the possibility that acacetin has a potential role in inhibiting the progression of atherosclerosis.