Objective: To observe the effect of electroacupuncture (EA) at "Zusanli"(ST36)-"Sanyinjiao"(SP6) on glucose and lipid metabolism and insulin resistance (IR) in obese diabetic rats, so as to explore its mechanism underlying improvement of obesity diabetes.
Methods: SPF male rats were randomly divided into normal control, model, meridian-acupoint EA (acupoint), non-meridian non-acupoint EA (non-acupoint), and medication (metformin) groups, with 10 rats in each group. The diabetes model was established by feeding the rats with high-fat diet for 8 weeks. EA (1.5 mA, 10 Hz/100 Hz) was applied to unilateral ST36 and SP6 for 20 min, once daily (except Sundays) for 4 weeks. Rats of the medication group were treated by gavage of metformin (300 mg/kg) once daily for 4 weeks (except Sundays). The body weight and length were measured and the Lee's index was calculated. The contents of total cholesterol (TC), triglyceride (TG), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C) in the plasma were detected by using a full-automatic biochemical analyzer. The content of fasting serum insulin (FINS) was assayed by using radioimmunoassay, the fasting blood glucose (FBG) was measured, and serum superoxide dismutase (SOD) activity by using xanthine oxidase method, serum malondialdehyde (MDA) by color method, serum glutathione peroxidase (GSH-Px) activity by indirect method, reactive oxygen species (ROS) by Dithio-bis-nitrobenzoic acid (DTNB) direct method, and the homeostasis model assessment of IR (HOMA-IR) and insulin sensitive index (ISI) were calculated. The expression levels of pancreatic tissue P66shc mRNA and PKCβ mRNA were detected by using RT-PCR, and the histopathological changes of the liver and adipose tissues were observed after H.E. staining.
Results: Compared with the normal control group, the Lee's index, levels of FBG, FINS, HOMA-IR, TC, TG, LDL-C, MDA, ROS, and P66shc mRNA and PKCβ mRNA expressions were significantly increased (P<0.05，P<0.01), and ISI, HDL-C, SOD, GSH-Px significantly decreased (P<0.05, P<0.01) in the model group. After the interventions, the levels of Lee's index,levels of FBG, FINS, HOMA-IR, TC, TG, LDL-C, MDA, ROS, and expressions of P66shc mRNA and PKCβ mRNA were remarkably down-regulated (P<0.05, P<0.01), and those of ISI, HDL-C, SOD, and GSH-Px up-regulated (P<0.05, P<0.01) in both EA and medication groups. H.E. staining showed many white adipocytes in the adipose tissue, radial and cord-like arrangement of liver cells, and many of them with vacuoles in the cytoplasm of small vesicular lipid droplets in the model group; and relative reduction of white adipocytes in number, smaller in cell body, and no obvious abnormal changes of structure and arrangement of liver cells in the EA and medication groups.
Conclusion: EA of ST36 and SP6 can improve glucose and lipid metabolism and IR in obese diabetic rats, which may be related to its function in suppressing PKCβ/P66shc signaling and oxidative stress.
目的：观察针刺“足三里”“三阴交”对肥胖糖尿病大鼠糖脂代谢及胰岛素抵抗的影响，探讨针刺改善肥胖糖尿病的作用机制。方法：SPF级雄性大鼠随机分为正常对照组、模型对照组、针刺干预组、非经非穴组、二甲双胍组，每组10只。高脂饲料持续喂养8周联合链脲佐菌素腹腔注射复制肥胖糖尿病大鼠模型。针刺干预组电针“足三里”“三阴交”，非经非穴组电针“足三里”“三阴交”旁开5 mm处，20 min/次；二甲双胍组予300 mg/kg二甲双胍灌胃。记录大鼠体质量和体长，计算Lee’s指数，监测空腹血糖(FBG)及血脂，ELISA法检测空腹血清胰岛素(FINS)水平并计算胰岛素抵抗指数(HOMA-IR)和胰岛素敏感指数(ISI)，TBA比色法检测血清丙二醛(MDA)水平，黄嘌呤氧化酶法检测血清超氧化物歧化酶(SOD)活性，三硫代双硝基苯甲酸直接法测定血清谷胱甘肽过氧化物酶(GSH-Px)水平，活性氧(ROS)试剂盒检测血清ROS水平，RT-PCR技术检测胰腺组织中P66shc、PKCβ mRNA表达水平，HE染色法观察肝脏、脂肪组织病理形态变化。结果：与正常对照组比较，模型对照组Lee’s指数、FBG、FINS、HOMA-IR及血浆总胆固醇(TC)、甘油三酯(TG)、低密度脂蛋白胆固醇(LDL)及血清MDA水平、ROS活性及胰腺组织中P66shc、PKCβ mRNA表达水平均升高(P<0.05,P<0.01)，ISI、血浆高密度脂蛋白胆固醇（HDL）和血清SOD、GSH-Px水平均降低(P<0.05,P<0.01)；与模型对照组比较，针刺干预组、二甲双胍组Lee’s指数、FBG、FINS、HOMA-IR及血浆TC、TG、LDL及血清MDA水平、ROS活性及胰腺组织中P66shc、PKCβ mRNA表达水平均降低(P<0.05,P<0.01)，ISI、血浆HDL和血清SOD、GSH-Px水平均升高(P<0.05,P<0.01)。模型对照组、非经非穴组可见许多白色脂肪细胞分布，正常对照组、针刺干预组、二甲双胍组白色脂肪细胞较模型对照组及非经非穴组明显减少，细胞形态变小。正常对照组、针刺干预组、二甲双胍组肝脏细胞排列呈索状，结构清晰，模型对照组、非经非穴组肝脏细胞仍呈放射状排列，但较多肝细胞胞质内有小泡状脂滴空泡。结论：针刺“足三里”“三阴交”可以改善肥胖糖尿病大鼠的糖脂代谢及胰岛素抵抗，这一作用可能与PKCβ/P66shc信号通路及氧化应激有关。.
Keywords: Electroacupuncture; Obesity diabetes; Oxidative stress; PKCβ/P66shc signaling.