电针对肥胖胰岛素抵抗大鼠下丘脑TLR4/IκBα/NF-κB信号通路的影响

Effect of electroacupuncture on insulin sensitivity and TLR4/IκBα/NF-κB signaling in hypothalamus of obese rats with insulin resistance

目的:观察电针对肥胖胰岛素抵抗(OIR)大鼠下丘脑Toll样受体4(TLR4)/核因子κB抑制剂α(IκBα)/核因子-κB(NF-κB)信号通路的影响,探讨电针治疗OIR的机制。方法:从42只Wistar雄性大鼠中随机挑选8只作为正常组,剩余大鼠给予高脂饲料喂养8周,建立OIR大鼠模型。将造模成功的16只大鼠随机分为模型组与电针组,每组8只。电针组大鼠给予"关元""中脘""足三里"及"丰隆"电针治疗,每周治疗3次,共治疗8周。分别在干预前及干预2、4、6、8周测量各组大鼠的体质量、空腹血糖和餐后血糖;在干预前及干预结束后行钳夹术检测葡萄糖输注率(GIR);在干预6周后,检测各组大鼠的腹腔注射糖耐量(IPGTT);分别采用荧光定量PCR及Western blot法检测下丘脑TLR4、NF-κB p65、磷酸化(p)-IκBα、肿瘤坏死因子-α(TNF-α)、白细胞介素1β(IL-1β)mRNA和蛋白表达。结果:与正常组比较,模型组大鼠体质量和餐后血糖显著升高(P<0.01),GIR显著降低(P<0.01);在IPGTT实验中,模型组大鼠注射葡萄糖90、120 min时血糖上升幅度显著大于正常组(P<0.01);下丘脑TLR4、p-IκBα、NF-κB p65、TNF-α、IL-1βmRNA及蛋白表达均显著升高(P<0.01)。与模型组比较,电针组大鼠体质量、餐后血糖分别于干预6周、2周后显著下降(P<0.05,P<0.01);干预8周后电针组大鼠GIR显著上升(P<0.05);在IPGTT实验中,电针组大鼠注射葡萄糖60 min时血糖上升幅度显著小于模型组(P<0.05);下丘脑TLR4、p-IκBα、NF-κB p65、TNF-α、IL-1βmRNA及蛋白表达均显著降低(P<0.01)。结论:电针能降低OIR大鼠体质量,改善IR,其机制可能与电针下调下丘脑TLR4/IκBα/NF-κB信号通路,减少炎性因子TNF-α、IL-1β的产生有关。

Objective To observe the effects of electroacupuncture on the hypothalamic Toll-like receptor 4(TLR4)/inhibitor nuclear factor kappa-Bα(IκBα)/nuclear factor-κB(NF-κB)signaling pathway in obese insulin resistance(OIR)rats,so as to explore the mechanism of EA underlying improving of insulin resistance.Methods Rats were randomly divided into normal,model and EA groups,with 8 rats in each group.The rat model of OIR was established by feeding with high-fat diet for 8 weeks.EA(2 Hz,1 mA)was applied to unilateral"Zusanli"(ST36),"Fenglong"(ST40),"Zhongwan"(CV12)and"Guanyuan"(CV4)for 10 min,3 times a week for 8 weeks.The body mass,fasting blood glucose(FBG)and postprandial blood glucose(PBG)were measured before and after 2、4、6、8 weeks’intervention.An intraperitoneal injection glucose tolerance test and hyperglycemic clamps were applied to test insulin resistance.The expression of TLR4、p-IκBα、NF-κB p65、TNF-α、IL-1β mRNA and protein in hypothalamus was detected by quantitative real-time PCR and Western blot,separately.Results Compared with the normal group,the body mass and PBG of the model group were significantly increased(P<0.01);glucose infusion rate(GIR)was significantly reduced(P<0.01);in the IPGTT test,the increase in blood glucose was significantly greater after 90 and 120 min of glucose injection(P<0.01);the hypothalamus TLR4,NF-κB p65,p-IκBα,TNF-α,IL-1β mRNA and protein expressions were all significantly increased(P<0.01).After EA intervention,the body weight and PBG were significantly down-regulated after 6 weeks and 2 weeks of intervention(P<0.05,P<0.01);GIR were significantly up-regulated after 8 weeks of intervention(P<0.05);In the IPGTT test,the increase in blood glucose 60 min after glucose injection was significantly down-regulated(P<0.05);hypothalamus TLR4,NF-κB p65,p-IκBα,TNF-α,IL-1β mRNA and protein expression were significantly down-regulated(P<0.01).Conclusion EA can reduce the body weight of OIR rats and improve IR,which may be related to down-regulating the hypothalamic TLR4/IκBα/NF-κB signaling pathway.