Zhuang Shu-Ting, Li Rui, Song Shan-Shan, Duan Hao-Ru, Li Qiu-Yan
School of Acupuncture-Moxibustion and Tuina, Beijing University of CM, Beijing 100029, China.
Zhongguo Zhen Jiu. 2022 Sep 12;42(9):1024-8. doi: 10.13703/j.0255-2930.20210725-k0004.
To observe the effect of electroacupuncture (EA) on protein expressions of suppressor of cytokine signaling 3 (SOCS3) and insulin receptor substrate-1 (IRS-1) in hypothalamus and morphology of pancreas islet in Zucker diabetic fatty (ZDF) rats, and to explore its possible mechanism on improving plasma glucose and insulin resistance of type 2 diabetes mellitus (T2DM).
Twelve SPF male ZDF rats were selected and fed with high-fat diet for 4 weeks to establish the T2DM model, after modeling, the rats were randomly divided into a model group and an EA group, 6 rats in each one. Besides, 6 SPF male Zucker lean rats were selected as a blank group. In the EA group, EA was applied at "Pishu" (BL 20), "Weiwanxiashu" (EX-B 3), "Zusanli" (ST 36) and "Sanyinjiao" (SP 6), with continuous wave, 15 Hz in frequency, 2 mA in intensity, once a day, 20 min each time, 6 times a week for 4 weeks. The fasting plasma glucose (FPG) was measured before and after intervention. The serum level of fasting insulin (FINS) was measured by radioimmunoassay, and the homeostasis model assessment of insulin resistance index (HOMA-IR) was calculated; the morphological change of pancreas islets was observed by HE staining; the protein expressions of SOCS3 and IRS-1 in hypothalamus were detected by Western blot.
Before intervention, compared with the blank group, FPG in the model group and the EA group was increased (<0.01). After intervention, compared with the blank group, FPG, serum level of FINS and HOMA-IR were increased (<0.01), the protein expression of SOCS3 was increased while IRS-1 was decreased in the hypothalamus in the model group (<0.01). Compared with the model group, FPG, serum level of FINS and HOMA-IR were decreased (<0.01), the protein expression of SOCS3 was decreased while IRS-1 was increased in the hypothalamus in the EA group (<0.01). In the model group, the shape of pancreas islets was irregular, the area of pancreas islets and the number of islet β cell nuclei were decreased, the nuclei of islet β cell was compensatory enlargement. In the EA group, the shape and the area of pancreas islets and the number of islet β cell nuclei were improved, the compensatory increase of islet β cell nuclei was alleviated compared with the model group.
Electroacupuncture can reduce the fasting plasma glucose, improve the morphology of pancreas islets, and alleviate the insulin resistance in ZDF rats. The mechanism may relate to the down-regulation of SOCS3 and up-regulation of IRS-1 in the hypothalamus, and improving the function of hypothalamus in regulating peripheral glucose metabolism.
观察电针对Zucker糖尿病脂肪（ZDF）大鼠下丘脑细胞因子信号转导抑制因子3（SOCS3）和胰岛素受体底物-1（IRS-1）蛋白表达及胰岛形态的影响，探讨其改善2型糖尿病（T2DM）大鼠血糖及胰岛素抵抗的可能机制。
选取12只SPF级雄性ZDF大鼠，高脂饮食喂养4周建立T2DM模型，造模后将大鼠随机分为模型组和电针组，每组6只。另选取6只SPF级雄性Zucker瘦鼠作为空白组。电针组于“脾俞”（BL 20）、“胃下俞”（EX-B 3）、“足三里”（ST 36）、“三阴交”（SP 6）穴行电针治疗，连续波，频率15 Hz，强度2 mA，每日1次，每次20 min，每周6次，共4周。干预前后测定空腹血糖（FPG）。采用放射免疫法测定空腹胰岛素（FINS）水平，计算胰岛素抵抗稳态模型评估指数（HOMA-IR）；HE染色观察胰岛形态变化；Western blot检测下丘脑SOCS3和IRS-1蛋白表达。
干预前，与空白组比较，模型组和电针组FPG升高（<0.01）。干预后，与空白组比较，模型组FPG、FINS水平及HOMA-IR升高（<0.01），下丘脑SOCS3蛋白表达升高，IRS-1蛋白表达降低（<0.01）。与模型组比较，电针组FPG、FINS水平及HOMA-IR降低（<0.01），下丘脑SOCS3蛋白表达降低，IRS-1蛋白表达升高（<0.01）。模型组胰岛形态不规则，胰岛面积及胰岛β细胞核数量减少，胰岛β细胞核代偿性增大。电针组与模型组比较，胰岛形态、面积及胰岛β细胞核数量改善，胰岛β细胞核代偿性增大减轻。
电针可降低ZDF大鼠空腹血糖，改善胰岛形态，减轻胰岛素抵抗。其机制可能与下调下丘脑SOCS3、上调IRS-1，改善下丘脑调节外周糖代谢功能有关。
