葛根对2型糖尿病大鼠胰腺内质网应激相关蛋白GRP78,ATF6表达的影响

Effect of Puerariae Lobatae Radix on Expression of Endoplasmic Reticulum Stress Related Proteins GRP78 and ATF6 in T2DM Rats

目的:观察葛根对2型糖尿病(T2DM)大鼠的疗效及其相关作用机制。方法:90只SD大鼠分为正常组、模型组、二甲双胍组、葛根高、中、低剂量组,每组15只。对非正常组大鼠高脂高糖饲料喂养4周后采用一次性腹腔注射链脲佐菌素(STZ)40 mg·kg^-1制造T2DM模型。葛根高、中、低剂量组分别灌胃葛根浸膏2.1,1.4,0.7 g·kg^-1,二甲双胍组灌胃盐酸二甲双胍0.2 g·kg^-1,正常组和模型组灌胃等体积蒸馏水,1次/d。灌胃8周后,测量大鼠空腹血糖(FBG),糖化血清蛋白(GSP),胰岛素(FINS),甘油三脂(TG),胆固醇(TC)含量,并计算胰岛素抵抗指数(HOMA-IR);免疫组化观察胰腺组织中肿瘤坏死因子-α(TNF-α)的表达;蛋白免疫印迹法(Western blot)检测胰腺组织中葡萄糖调节蛋白78(GRP78),活化转录因子6(ATF6)蛋白的表达。结果:与正常组比较,模型组的FBG,GSP,TG,TC,FINS,TNF-α含量明显增高(P<0.05),HOMA-IR指数明显上升(P<0.05),胰腺组织中GRP78,ATF6蛋白表达明显增高(P<0.05);与模型组比较,二甲双胍组、葛根高、中、低剂量组FBG,GSP,TG,TC,FINS,TNF-α含量均明显降低(P<0.05),HOMA-IR指数明显降低(P<0.05),胰腺组织中GRP78,ATF6蛋白表达明显降低(P<0.05)。结论:葛根可以显著改善T2DM大鼠胰岛素抵抗,抑制胰腺组织中炎症因子TNF-α的表达,减少胰腺组织中内质网应激相关蛋白GRP78,ATF6的表达。

Objective: To observe the effect of Puerariae Lobatae Radix on type 2 diabetes mellitus(T2 DM)rats and related mechanism. Method:Ninety SD rats were divided into normal group,model group,metformin group,Puerariae Lobatae Radix high dose group,Puerariae Lobatae Radix medium dose group and Puerariae Lobatae Radix low dose group,15 rats in each group. The rats in abnormal group were fed with highfat and high sugar diet for 4 weeks,and then T2 DM model was established by intraperitoneal injection of40 mg·kg^-1 streptozotocin(STZ). Puerariae Lobatae Radix high-dose group was intragastrically administered with 2.1 g·kg^-1 of Puerariae Lobatae Radix extract powder,Puerariae Lobatae Radix medium-dose group was intragastrically administered with 1.4 g·kg^-1 of Puerariae Lobatae Radix extract powder,Puerariae Lobatae Radix low-dose group was intragastrically administered with 0.7 g·kg^-1 of Puerariae Lobatae Radix extract powder,0.2 g·kg^-1 of metformin hydrochloride in metformin group,distilled water once a day in normal group and model group. After 8 weeks,fasting blood glucose(FBG),glycosylated serum protein(GSP),insulin(FINS),triglyceride(TG),cholesterol(TC)were measured,and insulin resistance index(HOMA-IR)was calculated. The expression of tumor necrosis factor-α(TNF-α)was observed by immunohistochemistry. Western blot was used to detect the protein expression of glucose regulatory protein 78(GRP78),activated transcription factor 6(ATF6)in pancreatic tissue. Result: Compared with normal group,the contents of FBG,GSP,TG,TC,FINS,TNF-α in model group were significantly increased(P<0.05),the HOMA-IR was significantly increased(P<0.05), the protein expressions of GRP78 and ATF6 in pancreatic tissue were significantly increased(P<0.05). Compared with model group,the contents of FBG,GSP,TG,TC,FINS and TNF-α in the metformin group and Puerariae Lobatae Radix high,medium and low dose groups were significantly decreased(P<0.05),HOMA-IR decreased significantly(P<0.05),and the expression of GRP78 and ATF6 protein in pancreatic tissue decreased significantly(P<0.05). Conclusion: Puerariae Lobatae Radix can significantly improve insulin resistance in T2 DM rats,inhibit the expression of inflammatory factor TNF-α in pancreatic tissue,reduce the protein expression of GRP78 and ATF6 in pancreatic tissue.