Effects of herbal cake-partitioned moxibustion on plasma trimethylamine, trimethylamine-N-oxide, and flavin-containing monooxygenase 3 in atherosclerotic rabbits

Objective To investigate the effects of herbal cake-partitioned moxibustion on the plasma levels of trimethylamine (TMA), trimethylamine-N-oxide (TMAO), and flavin-containing monooxygenase 3 (FMO3) in rabbits with atherosclerosis (AS), as well as to explore the possible mechanism of herbal cake-partitioned moxibustion in treating AS. Methods After 1-week adaptive feeding, 28 male New Zealand rabbits were divided into a blank group, a model group, an antibiotic group, and a herbal cake-partitioned moxibustion group according to the random number table method, with 7 rabbits in each group. Rabbits were fed with a basic diet in the blank group, while with a basic diet plus 1% choline in the remaining groups to prepare the AS model. Rabbits were given drinking water with broad-spectrum antibiotics in the antibiotic group, and herbal cake-partitioned moxibustion in the herbal cake-partitioned moxibustion group for 12 weeks. The atherosclerotic plaques by hematoxylin-eosin (HE) staining, the blood lipid levels, the plasma TMA and TMAO levels by liquid chromatography-mass spectrometry were detected for rabbits in each group at the end of interventions. Liver FMO3 protein expression was detected by Western blotting. Liver FMO3 mRNA expression was detected by real-time fluorescence quantitative polymerase chain reaction. Results HE staining showed that the arterial wall was rough, the intima was significantly thickened, and more foam cells and lipid deposits were seen in rabbits of the model group. Arterial wall thickening was not obvious with a few foam cells and lipid deposits in the herbal cake-partitioned moxibustion group. Compared with the blank group, the serum levels of low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) were increased ( P <0.01), the plasma levels of TMA and TMAO were increased ( P <0.05, P <0.01), and the expression levels of liver FMO3 protein and mRNA were all increased ( P <0.05, P <0.01); while the serum high-density lipoprotein cholesterol (HDL-C) level was decreased in the model group ( P <0.05). Compared with the model group, the LDL-C and TC levels were decreased ( P <0.01 or P <0.05), the HDL-C levels were increased ( P <0.01), the TMA and TMAO levels were decreased ( P <0.05), while the protein and mRNA expression levels of FMO3 were decreased without statistical significance in the herbal cake-partitioned moxibustion group and the antibiotic group. Conclusion Herbal cake-partitioned moxibustion can slow atherosclerotic plaque formation and regulate lipid levels in AS rabbits, and the mechanism may be related to the down-regulation of TMA and TMAO expression in the plasma.