电针对胰岛素抵抗肥胖大鼠炎性反应和肠道屏障的影响

Effects of electroacupuncture on inflammatory response and intestinal mucosal barrier in obese rats with insulin resistance

目的:观察电针对胰岛素抵抗肥胖大鼠炎性反应和肠道屏障的影响,探讨电针改善大鼠胰岛素抵抗状态的机制。方法:将45只Wistar雄性大鼠随机挑选15只采用普通饲料喂养,8周后随机挑选10只直接进入正常组。余下30只大鼠采用高脂饲料喂养8周建立肥胖大鼠模型,将造模成功的28只大鼠随机进行编号,并挑选20只随机分入模型组与电针组,每组10只。同时,在模型组和电针组各随机取3只行高胰岛素-正葡萄糖钳夹术以确定胰岛素抵抗模型是否造模成功。造模结束后,电针组选取"中脘""关元""足三里"及"丰隆"穴,其中"足三里"和"丰隆"穴左右两侧交替使用,连续波,频率2 Hz,强度1 mA,留针10 min,隔日1次,每周干预3次,共干预8周。干预期间正常组及模型组大鼠同样抓取固定但不干预。分别在干预前及干预8周后测量各组大鼠的体质量、餐后血糖。在干预6周后,每组取3只大鼠行钳夹术以检测全身胰岛素敏感性。各组大鼠处死前,心尖取血检测血清胰岛素含量,大鼠处死后,采用Real time-PCR法检测肝脏和脂肪组织肿瘤坏死因子α(TNF-α)、白介素6(IL-6)和结肠组织闭合蛋白(occludin)、闭合小环蛋白(ZO-1)的mRNA水平,采用Western blot法检测结肠组织occludin、ZO-1蛋白表达。结果:与正常组相比,模型组大鼠体质量、餐后血糖及血清胰岛素含量均显著升高,葡萄糖输注速率(glucose infusion rate,GIR)显著降低(均P<0.01),肝脏及脂肪组织TNF-α、IL-6 mRNA表达升高(P<0.05,P<0.01),结肠组织ZO-1mRNA和蛋白表达显著降低(均P<0.01),结肠组织occludin mRNA表达显著降低(P<0.01);与模型组相比,电针组大鼠体质量、餐后血糖、血清胰岛素含量及肝脏和脂肪组织TNF-α、IL-6 mRNA在干预后降低(P<0.01,P<0.05),GIR显著升高(P<0.01),结肠组织ZO-1 mRNA和蛋白表达升高(P<0.01,P<0.05)。结论:电针能够降糖,增加胰岛素敏感性,其机制可能与抑制炎性因子表达,改善肠黏膜屏障作用有关。

Objective To observe the effects of electroacupuncture(EA) on inflammatory response and intestinal mucosal barrier in obese rats with insulin resistance, and to explore the mechanism of EA on improving insulin resistance in rats. Methods Among 45 Wistar male rats, 15 rats were randomly selected and fed with common diet. After eight weeks, 10 rats were randomly selected and divided into the normal group. The remaining 30 rats were fed with high-fat diet for 8 weeks to establish obesity model of rat, among 28 rats with successful model of obesity, 20 rats were randomly selected and divided into the model group and EA group, 10 rats in each one. At the same time, 3 rats in the model group and the EA group were randomly selected for hyperinsulinemia-euglycemic clamp operation to determine whether the insulin resistance model was successful. After model establishment, the rats in the EA group were intervented with EA at "Zhongwan"(CV 12), "Guanyuan"(CV 4), "Zusanli"(ST 36) and "Fenglong"(ST 40) with continuous wave, frequency of 2 Hz and intensity of 1 mA;"Zusanli"(ST 36) and "Fenglong"(ST 40) were used alternately on both sides;the needles were sustained for 10 min;EA was given once every other day, three times a week for a total of 8 weeks. During the intervention, the rats in the normal group and the model group were fixed but not intervented. The body mass and postprandial blood sugar were measured in each group before and after 8-week intervention. After 6-week intervention,3 rats in each group were clamped to detect systemic insulin sensitivity. Before the rats were killed, blood was taken from the apex of the heart to detect the serum insulin content. After the rats were killed, the mRNA levels of tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) in liver and adipose tissue and occlidin and ZO-1 in colon tissue were detected by Real time-PCR;the protein expression levels of occludin and ZO-1 in colon tissue were detected by Western blot method. Results Compared with the normal group, the body mass, postprandial blood sugar and serum insulin content in the model group were increased significantly, the glucose infusion rate(GIR) was decreased significantly(all P<0.01), the mRNA expressions of TNF-a and IL-6 in liver and adipose tissue were increased(P<0.05, P<0.01), the mRNA and protein expressions of ZO-1 in colon tissue were decreased significantly(both P<0.01), and the mRNA expression of occludin was significantly decreased(P<0.01). Compared with the model group, the body mass, postprandial blood sugar, serum insulin content, mRNA expressions of TNF-a and IL-6 in liver and adipose tissue were significantly decreased(P<0.01, P<0.05), GIR was significantly increased(P<0.01), and the mRNA and protein expressions of ZO-1 in colon tissue were increased(P<0.01, P<0.05). Conclusion EA could decrease blood sugar and increase insulin sensitivity. Its mechanism may be related to inhibiting the expression of inflammatory factors and improving intestinal mucosal barrier.