Effects of acupuncture on TMAO, CD36 expression, and cholesterol deposition in atherosclerotic mice.

OBJECTIVES

To observe the effects of acupuncture (acupuncture for regulating middle and promoting meridians) on trimethylamine-N-oxide (TMAO), CD36 expression, and cholesterol deposition in atherosclerotic (AS) mice, exploring potential mechanism of electroacupuncture (EA) in treating AS.

METHODS

A total of 31 male SPF-grade C57BL/6J ApoE-/- mice were fed with high-fat diet for 8 weeks to establish AS model. After successful modeling, the remaining 30 mice were randomly divided into a model group, a medication group, and an EA group, with 10 mice in each group. An additional 10 normal mice of the same strain were selected as a blank group. The mice in the blank group and the model group received no intervention. The mice in the medication group were treated with intragastric administration of atorvastatin calcium. The mice in the EA group were treated with EA at "Neiguan" (PC 6), "Tianshu" (ST 25) and "Zusanli" (ST 36). The same-side "Neiguan" (PC 6) and "Zusanli" (ST 36), "Tianshu" (ST 25) and the tail of the mice were connected to the EA apparatus, with disperse-dense wave, a frequency of 2 Hz/15 Hz, and a current intensity of 0.3 mA for 10 min per session. Acupuncture was performed unilaterally per session, alternating between the left and right sides, with a frequency of once every other day. After intervention, HE staining was used to observe the pathological morphology of the aorta. Microplate assays were conducted to measure triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels in serum. Ultra high performance liquid chromatography-mass spectrometry technique (UPLC-MS) was employed to detect TMAO level in plasma. Western blot was performed to assess CD36 protein expression level in the aorta. Microanalysis was used to measure cholesterol ester (CE) level in the aorta and the CE/TC ratio was calculated.

RESULTS

Compared with the blank group, the mice in the model group exhibited significant pathological changes of atherosclerosis, serum TG, TC, LDL-C levels were increased (<0.01), and HDL-C level was decreased (<0.01); the plasma TMAO level, aortic CE level, and the CE/TC ratio were increased (<0.01), along with elevated CD36 protein expression level in the aorta (<0.01). Compared with the model group, the mice in the medication group and the EA group showed improvements in aortic pathology, serum TG, TC, LDL-C levels were reduced, HDL-C levels were increased (<0.05); plasma TMAO levels, aortic CE levels, and the CE/TC ratio were decreased (<0.01), and CD36 protein expression levels were lowered (<0.05). The serum TG and TC levels in the EA group were higher than those in the medication group (<0.05).

CONCLUSIONS

The acupuncture can ameliorate aortic pathological changes, regulate blood lipid levels, reduce plasma TMAO level, inhibit CD36 protein expression in the aorta, and decrease cholesterol deposition. These effects may contribute to the therapeutic mechanism of EA in treating AS.