| ObjectivesThis study was designed to establish animal model of insulin resistance (IR) through the high-fat diet in Wistar rats, therefore, to observe the effect of electroacupuncture (EA) therapy on the IR and the expression of SIRT1in the skeletal muscle of insulin resistance rats, and to investigate the involved mechanism.MethodsForty Wistar rats (female and male by half) at the age of eight weeks, were randomly divided into normal control group (n=16) and high-fat diet group (n=24) by female and male.The former was given basal diet (total calories is3.8kcal/g, including carbohydrate70%, protein20%and fat10%) and the latter was given high-fat diet (total calories is5.4kcal/g, including carbohydrate38.5%, protein15%and fat46.5%). Eight weeks later, eight rats (female and male by half) were randomly selected from each group to be administered euglycemic-hyperinsulinemic clamp technique (EHCT) to evaluate the condition of IR. After the models were established, the high-fat diet group were divided into two subgroups:model control group (MC group, n=8) and electroacupuncture group (EA group, n=8), and the remained normal control group (NC group, n=8). We adopted stainless steel filiform needle with15mm in length and0.30mm in diameter, chose acupoints of "Zusanli (ST36)","Fenglong (ST40)","Guanyuan (GV4)" and "Zhongwan (RN12)" for EA group. The acupoints of "Zusanli (ST36)" and "Fenglong (ST40)" were penetrated3-5mm perpendicularly and the other two acupoints were punctured3-5mm obliquely. After rotating for1minute, needles were interconnected with a Hans acupoint nerve stimulator (HANS) EA apparatus, and the following stimulus parameters were selected:continuous-wave at2Hz and1mA,10minutes per day, five days per week for eight weeks. The ipsilateral "Zusanli" and "Fenglong" were connected with the two electrodes of the same output, while "Guanyuan" and "Zhongwan" were connected with the two electrodes of another output. The rats were fixed in special clothes when receiving EA. NC group and MC group recieved no treatment while were grabbed and fixed at the same time with the same method. After treating for six weeks, the intraperitoneal insulin tolerance test (IPITT) and intraperitoneal glucose tolerance test (IPGTT) of all the rats were measured. After treating for eight weeks, all rats were weighed and tested fasting blood-glucose and postprandial blood-glucose by fast blood glucose apparatus. Moreover, all the rats were sacrificed quickly to take the quadriceps femoris. SIRT1protein expression in the skeletal muscle was detected by western blot and analysed by image analysis system. All the data were analyzed through a statistical analysis system.Results1. After eight weeks, body weight of the rats in high-fat diet group was increased significantly compared to that of the normal control group (P<0.01). The level of blood-glucose was kept relatively stable though adjusting the GIR blood glucose in EHCT. The rats’GIR in high-fat feed group was decreased significantly while compared with that of the normal control group(P<0.01).2. After eight weeks, the rats’body weight in EA group was decreased as compared with MC group (P<0.05). The rats’FBG and PBG levles were lower in EA group, but no significant differences were found in other groups (P>0.05)3. After treating six weeks, the IPGT and IPIT of rats in EA group were significantly decreased compared to MC group (P<0.05, P<0.01).4. After eight weeks of treatment, the protein expression of SIRT1in quadriceps nuclear in EA group was significantly increased compared to MC group (P<0.01).Conclusions1. IR rats model were successfully induced with Wistar rats feeded by high-fat diet for eight weeks.2. EA could reduce the body weight in IR rats, decrease IPGT and IPIT, and improve insulin resistance.3. EA could significantly increase the level of protein expression of SIRT1in quadriceps nuclear, which may be closely related to the mechanism that EA improved insulin sensitivity. |
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