Published online Sep 14, 2020. doi: 10.3748/wjg.v26.i34.5118
Peer-review started: May 19, 2020
First decision: June 20, 2020
Revised: June 30, 2020
Accepted: August 14, 2020
Article in press: August 14, 2020
Published online: September 14, 2020
Non-alcoholic fatty liver disease (NAFLD), in which abnormal lipid metabolism plays an important role in disease progression, has become a pandemic. Abnormal lipid metabolism, for example an increased fat intake, has been thought to be an initial factor leading to NAFLD. The small intestine is the main site of dietary lipid absorption. A number of clinical trials have shown that acupuncture has positive effects in the regulation of lipid metabolism, which is closely associated with the progression of NAFLD. We therefore hypothesized that, acupuncture can improve the conditions of NAFLD by regulating intestinal absorption of lipid.
To study the role of acupuncture treatment in the improvement of metabolic syndrome secondary to NAFLD by mouse model.
8-wk-old male C57BL/6J mice were fed a methionine- and choline-deficient diet for 3 wk. Then, all mice were separated randomly into acupoints group (AG) or non-acupoints group (NG) with high fat diet feeding. Needling treatment was performed at Zu san li, Guan yuan and Yong quan acupoints as acupuncture treatment to AG mice while non-acupoints place to NG mice. Finally, mice were anesthetized with an injection of ketamine-medetomidine and euthanized by exsanguination.
An apparent improvement of obesity was found in AG mice after acupuncture treatment. In AG mice, the body weight was much lower (22.6 ± 1.2 g vs 28.1 ± 1.0 g, P < 0.005) in comparison to NG mice. The length of small intestine in AG mice was significantly shorter (26.7 ± 2.3 cm vs 32.7 ± 2.7 cm, P < 0.005). A large amount of chyme was observed in the lumen of the AG small intestine. The expression of microsomal triglyceride transfer protein, apolipoprotein B and apolipoprotein C2 was downregulated. Triacylglycerols (TGs), total cholesterol and nonesterified fatty acid (NEFA) levels of the small intestinal tissue were significantly higher in AG mice, but the serum TGs and NEFA levels were reduced in AG mice.
These results indicate that acupuncture at Zu san li, Guan yuan and Yong quan suppressed lipid absorption by downregulating the expression of apolipoproteins in the small intestine.
Core Tip: In the present study, our experimental data showed that acupuncture treatment suppressed high-fat-induced body weight gain, reduced the accumulation of intra-abdominal fat, inhibited lipid absorption in the small intestine and downregulated the blood lipid level in mice with non-alcoholic fatty liver disease, suggesting that acupuncture potentially had variable beneficial effects in improving the lipid metabolism in the presence of abnormal liver metabolism. Furthermore, we also found more fat deposition in the intestinal epithelium with the decreased expression of some intestinal apolipoproteins in acupuncture-treated mice, suggesting that acupuncture may suppress lipid absorption by downregulating the expression of apolipoproteins in the small intestine.