Effect of acupuncture on macrophage polarization of white adipose tissue in obese mice induced by high-fat diet / 中国针灸

ABSTRACT

<p><b>OBJECTIVE</b>To observe the effect of acupuncture at acupoints and non-acupoints on macrophage polarization of white adipose tissue in obese mice induced by high-fat diet(HFD).</p><p><b>METHODS</b>Fifty male C57BL/6 mice were randomly divided into a control group (=10), and other mice were fed with HFD for 16 weeks to establish model. Thirty model mice, which were successfully established and continuously fed with HFD for 8 weeks, were randomized into a model group, a non-acupoint group and an acupuncture group (=10/group). The mice in the control group were continuously fed with common food for 8 weeks. From the second day after model established, the mice of the acupuncture group were treated with acupuncture at "Guanyuan" (CV 4), "Zusanli" (ST 36) and "Weiwanxiashu" (EX-B 3); the mice of the non-acupoint group were treated with acupuncture at two non-acupoints in tail, 15 min a time, once a day for 8 weeks. After model establishment and on the second day after the last acupuncture treatment, the body weight was recorded. The level of serum triglyceride (TG), total cholesterol (TC) in eye socket blood were measured. The morphological structure of epididymis white adipose tissue (eWAT) in mice was observed by hematoxylin and eosin (HE) staining. The mRNA expressions of interleukin-6 (IL-6), monocyte chemotactic protein 1 (MCP-1), tumor necrosis factor α (TNF-α), IL-10, inducible nitric oxide synthesis (iNOS), CD206 in eWAT of mice were determined with real-time quantitative PCR (RT-qPCR). The protein expressions of iNOS and CD206 in eWAT were determined with immunohistochemistry staining (IHC).</p><p><b>RESULTS</b>Compared with the control group, the body weight in the model, non-acupoint and acupuncture groups increased at the 16th and 24th weeks (all<0.05). Compared with the model group, the body weight of the acupuncture group at the 24th week decreased (<0.05). The serum TG and TC in the model group increased compared with those of the control group (both<0.05). The TC in the non-acupoint group decreased (<0.05), and the TG and TC in the acupuncture group decreased compared with those in the model group (both<0.05). Meanwhile, the mRNA expressions of MCP-1, TNF-α, IL-6 and iNOS in the model and non-acupoint groups increased compared with those in the control group (all<0.05), and the mRNA expressions of IL-10 and CD206 decreased (all<0.05). The mRNA expressions of MCP-1, TNF-α, IL-6 and iNOS in the acupuncture group were lower than those in the model group (all<0.05), and the mRNA expressions of IL-10 and CD206 were higher (both<0.05). HE staining showed alveolate adipose tissue in the control group with numbers of unilocular adipose cells, vacuolar polygon or circle. The adipose cells in the model group were larger and irregular with larger intercellular space. The adipose cells in the acupuncture group were minified with smaller intercellular space. Compared with those in the control group, the protein expressions of iNOS increased (both<0.05) and those of CD206 decreased (both<0.05) in the model and non-acupoint groups. Compared with those in the model group, the protein expression of iNOS decreased (<0.05) and that of CD206 increased (<0.05) in the acupuncture group.</p><p><b>CONCLUSION</b>Acupuncture can improve inflammation of obese mice through affecting macrophage polarization of white adipose tissue.</p>