Moxibustion at CV4 alleviates atherosclerotic lesions through activation of the LXRα/ABCA1 pathway in apolipoprotein-E-deficient mice

Abstract

Objectives: To investigate the anti-atherogenic effect of moxibustion and whether it is mediated through the reverse cholesterol transport process.

Methods: 8-week-old male apolipoprotein E deficient (ApoE^-/- knockout) mice were randomly divided into two groups (n=10 per group): atherosclerosis (AS) and AS plus moxibustion (AS+M). C57BL/6J mice of the same background (n=10) were selected as controls. Mice in the AS+M group received indirect moxibustion with an ignited moxa stick held over CV4. Mice of the AS and control groups were restrained in the same holder with an unlit moxa stick held over CV4. All treatments were performed for 20 min per day, 6 days per week for 12 weeks. After the treatment, the mice were euthanased and their serum lipids were measured. The aortic roots and thoracic aortas were collected for haematoxylin and eosin and red oil O staining, respectively, to analyse the atherosclerotic lesions. Expression of adenosine triphosphate binding cassette (ABCA)A1/G1 and liver X receptor α (LXRα) in the thoracic aorta were examined with Western blotting.

Results: The moxibustion-treated (AS+M) mice showed a significantly lower plaque area percentage in the aortic root and thoracic aorta, and higher expression of LXRα and ABCA1 in the thoracic aorta compared with the AS mice. No significant differences were found in average lipid area percentage in the thoracic aorta, or ABCG1 expression in the thoracic aorta, between mice in the AS+M and AS groups.

Conclusion: Moxibustion treatment at CV4 suppressed the progression of atherosclerotic lesions in ApoE^-/- mice. The anti-atherogenic effect of moxibustion may be achieved by: (1) regulation of lipid metabolism, and thus prevention of lipid accumulation; and (2) upregulation of LXRα- and ABCA1-mediated cholesterol efflux in the lesion area.

Keywords: atherosclerosis; cholesterol efflux; lipid metabolism; moxibustion; reverse cholesterol transport.

Figure 1.

Effect of moxibustion on levels of serum TC (A), TG (B), LDL (C), HDL (D) and ApoA-Ι (E). Data are expressed as mean±SD, n=10/ group. *P<0.05 versus AS, **P<0.01 versus AS. ApoA-I, apolipoprotein A-I; HDL-C, high density lipoprotein-cholesterol; LDL-C, low density lipoprotein-cholesterol; TC, total cholesterol; TG, triglyceride.

Figure 2.

(A) Representative histomorphological (HE stained) images of the aortic root (100×). Bar=500 µm. (B) Comparison of plaque area percentage between AS and AS+M groups. Data are expressed as mean±SD, n=10/ group. *P<0.05, AS+M versus AS. AS, atherosclerosis; M, moxibustion.

Figure 3.

(A) Representative histomorphological (red oil O stained) images of the thoracic aorta (100×). Bar=500 µm. (B) Comparison of plaque area percentage between AS and AS+M groups. (C) Comparison of lipid area percentage between AS and AS+M groups. Data are expressed as mean±SD, n=10/ group. *P<0.05, AS+M versus AS. AS, atherosclerosis; M, moxibustion.

Figure 4.

Effects of moxibustion on LXRα, ABCA1 and ABCG1 expression. (A–C) Representative Western blots using Odyssey software. (D–E) Comparison of LXRα, ABCA1, ABCG1 expression between the different groups. Protein expression levels were normalised to β-actin. Data are expressed as mean±SD, n=10/ group. *P<0.05 versus AS, **P<0.01 versus AS. AS, atherosclerosis; M, moxibustion; ABC, adenosine triphosphate binding cassette; LXR, liver X receptor.