Anti-atherosclerotic potential of baicalin mediated by promoting cholesterol efflux from macrophages via the PPARγ-LXRα-ABCA1/ABCG1 pathway.

BACKGROUND: Atherosclerosis (AS) is associated with severe cardiovascular disease. The anti-inflammatory, anti-oxidation, and lipid regulating properties of baicalin suggest potential as an anti-atherosclerotic agent. We therefore investigated whether baicalin can protect against the development of atherosclerosis in an AS rabbit model and explored the underling mechanisms in THP-1 macrophages. METHODS AND RESULTS: In vivo, treatment with baicalin markedly decreased atherosclerotic lesion sizes and lipid accumulation in AS rabbit carotid arteries. Western blotting revealed that the protein expression levels of both peroxisome proliferator-activated receptor gamma (PPARγ) and liver X receptor alpha (LXRα) were up-regulated in the baicalin group compared with the model group. In vitro, baicalin restricted oxidized-low density lipoprotein (ox-LDL)-induced intracellular lipid accumulation and foam cell formation in THP-1 macrophages. Molecular data showed that baicalin significantly increased the expression levels of PPARγ, LXRα, ATP binding cassette transporters (ABC) A1 and ABCG1. Cell transfection experiments (including PPARγ and LXRα siRNAs) suggested that the effects of baicalin are mediated by the PPARγ-LXRα signalling pathway, which stimulates the expression of ABCA1 and ABCG1. CONCLUSION: These results suggest that baicalin potentially exerts anti-atherosclerosis effects, possibly through the PPARγ-LXRα-ABCA1/ABCG1 pathway, by promoting efflux of cholesterol from macrophages and delaying the formation of foam cells.

Celastrol may have an anti-atherosclerosis effect in a rabbit experimental carotid atherosclerosis model.

BACKGROUND: Celastrol may have an anti-atherosclerosis effect. This study aimed to investigate if celastrol had an anti-AS effect using a rabbit experimental carotid atherosclerosis model. METHODS: Forty male Japanese white rabbits were divided into the sham group (normal diet), the model group (high fat diet), the group treated with celastrol (high fat diet) and the group treated with atorvastatin (high fat diet) randomly. The rabbits fed a high fat diet underwent balloon injury of the right common carotid artery and were treated with dimethyl sulfoxide (DMSO) (the model group, 3.5 ml/kg/d), celastrol and its dissolvent DMSO (the celastrol group, 1 mg/kg/d and 3.5 ml/kg/d) and atorvastatin and its dissolvent DMSO (the atorvastatin group, 2.5 mg/kg/d and 3.5 ml/kg/d) for 12 weeks by gavage. RESULTS: The ratio of the plaque area and the arterial wall cross-section area in the celastrol group was significantly less than the model group (P < 0.001), and there was no significant difference compared with the atorvastatin group. The serum level of LDL-C of the celastrol group was significantly lower than the model group (P = 0.014), and there was no significant difference compared with the atorvastatin group. The expression of VEGF in the celastrol group was significantly less compared with the model group (P = 0.014), whereas the expression of VEGF in the atorvastatin group and the model group showed no significant differences. CONCLUSION: Our findings suggest that celastrol effectively reduced the plaque ratio, decreased the serum levels of LDL and downregulated the expression of VEGF, suggesting an anti-AS effect of celastrol.