Effect of herb cake-insulated moxibustion on serum exosomal miR-223 expression in rabbits with atherosclerosis

Objective To investigate whether herb cake-insulated moxibustion affects the expression of cholesterol metabolism-related protein 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) and inhibits the development of atherosclerosis by regulating the exosomal miR-223 expression. Methods Thirty-six male New Zealand rabbits were randomly assigned to a normal group, a model group, and an herb cake-insulated moxibustion group, with 12 rabbits in each group. The model and the herb cake-insulated moxibustion groups were fed a high-fat diet for 8 weeks to induce an atherosclerosis model. Following successful modeling, the herb cake-insulated moxibustion group was subjected to bundling and herb cake-insulated moxibustion intervention, while the other two groups were subjected only to bundling without moxibustion. After 8 weeks of intervention, hematoxylin-eosin (HE) staining was used to observe aortic morphology; the serum levels of total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) were detected using an automatic biochemical analyzer in each group. Exosome morphology was observed using the transmission electron microscope; Western blotting (WB) was used to detect the protein levels of serum exosomal CD63 and CD9 markers, as well as liver HMGR; additionally, real-time fluorescence quantitative polymerase chain reaction was used to quantify serum exosomal miR-223. Results HE staining showed thickened aortic intima, lipid infiltration, foam cell aggregation, and structural damage to the arterial wall in the model group. Meanwhile, after modeling, the serum levels of LDL-C, TC, and TG increased significantly in the model and herb cake-insulated moxibustion groups compared to the normal group (P<0.05), suggesting successful atherosclerosis rabbit model preparation. The serum exosomes of rabbits in the model group exhibited a saucer-like or semi-concave spherical shape with diameters of 120-150 nm. WB detection results showed positive expression of the exosomal markers CD63 and CD9. After 8 weeks of intervention, the miR-223 level in the model group was significantly lower than that in the normal group (P<0.01). In contrast, the herb cake-insulated moxibustion group demonstrated significantly reduced serum levels of TC, TG, and LDL-C (P<0.05), increased miR-223 expression (P<0.01), and decreased relative liver HMGR protein expression (P<0.05) compared to the model group. Conclusion Herb cake-insulated moxibustion may alleviate the progression of atherosclerosis by up-regulating exosomal miR-223 expression and down-regulating HMGR protein expression, thereby inhibiting cholesterol anabolic metabolism.