葛根芩连汤对2型糖尿病db/db小鼠胰腺组织PERK/ATF4/CHOP信号通路的影响

Effects of Gegen Qinlian Decoction on PERK/ATF4/CHOP Signaling Pathway in Pancreatic Tissue of Mice with Type 2 Diabetes Mellitus

目的观察葛根芩连汤对2型糖尿病(T2DM)小鼠胰腺内质网应激的影响,探讨其治疗T2DM的作用机制。方法75只SPF级雄性db/db小鼠随机分为模型组、二甲双胍组和葛根芩连汤高、中、低剂量组,每组15只,15只db/m小鼠作为空白组,给药组分别予相应药物灌胃12周。检测小鼠体质量、空腹血糖(FBG)及糖化血红蛋白(HbA1c),HE染色观察胰腺组织病理变化,TUNEL染色检测胰岛细胞凋亡情况,Western blot检测胰腺组织葡萄糖调节蛋白78(GRP78)、蛋白激酶R样内质网激酶(PERK)、p-PERK、活化转录因子4(ATF4)、C/EBP同源蛋白(CHOP)蛋白表达,实时荧光定量PCR检测胰腺组织PERK、ATF4、CHOP mRNA表达。结果与空白组比较,模型组小鼠体质量、FBG和HbA1c含量显著增加(P<0.01);胰腺组织结构不完整,边界模糊,内有空泡,胰岛细胞凋亡明显增加(P<0.01);胰腺组织GRP78、p-PERK、ATF4、CHOP蛋白表达显著升高(P<0.01),PERK、ATF4、CHOP mRNA表达显著升高(P<0.01)。与模型组比较,各给药组小鼠体质量、FBG和HbA1c含量显著减少(P<0.05,P<0.01);胰腺组织病理改变有所减轻,胰岛细胞凋亡不同程度减少(P<0.05,P<0.01);葛根芩连汤高、中剂量组和二甲双胍组胰腺组织GRP78、p-PERK、ATF4、CHOP蛋白表达显著降低(P<0.01),PERK、ATF4、CHOP mRNA表达显著降低(P<0.05,P<0.01)。结论葛根芩连汤可能通过抑制内质网应激PERK/ATF4/CHOP信号通路,下调相关基因和蛋白表达,减少胰岛细胞凋亡,保护胰岛细胞功能,延缓T2DM进展。

Objective To observe the effects of Gegen Qinlian Decoction on pancreatic endoplasmic reticulum stress in mice with type 2 diabetes mellitus(T2DM);To explore its mechanism of action in the treatment of T2DM.Methods Totally 75 SPF male db/db mice were randomly divided into model group,metformin group,and Gegen Qinlian Decoction high-,medium-,low-dosage groups,with 15 mice in each group.15 db/m mice were set as the blank group.The administration groups received corresponding medicine for gavage for 12 weeks.Body mass,fasting blood glucose(FBG)and glycated hemoglobin(HbA1c)in mice were detected,HE staining was used to observe the pathological changes of pancreatic tissue,the apoptosis of islet cells was determined by TUNEL staining,Western blot was used to detect pancreatic tissue glucose regulatory protein 78(GRP78),protein kinase R-like endoplasmic reticulum kinase(PERK),p-PERK,activated transcription factor 4(ATF4)and C/EBP homologous protein(CHOP)protein expression,RT-PCR was used to detect pancreatic tissue PERK,ATF4,CHOP mRNA expressions.Results Compared with the blank group,the body mass,FBG and HbA1c contents in the model group significantly increased(P<0.01);the pancreatic tissue structure was incomplete,with blurry boundaries and vacuoles inside,leading to a significant increase in pancreatic islet cells apoptosis(P<0.01);the expressions of GRP78,p-PERK,ATF4,and CHOP proteins in pancreatic tissue significantly increased(P<0.01),and the mRNA expressions of PERK,ATF4 and CHOP significantly increased(P<0.01).Compared with the model group,the body mass,FBG and HbA1c contents of mice in each administration group significantly decreased(P<0.05,P<0.01);pathological changes in pancreatic tissue was reduced,and islet cells apoptosis decreased to varying degrees(P<0.05,P<0.01);the expressions of GRP78,p-PERK,ATF4 and CHOP proteins in pancreatic tissue significantly decreased(P<0.01)in Gegen Qinlian Decoction high-and medium-dosage groups and the metformin group,and the expressions of PERK,ATF4 and CHOP mRNA significantly decreased(P<0.05,P<0.01).Conclusion Gegen Qinlian Decoction may decreased pancreatic islet cells apoptosis,protect pancreatic cell function,and delay the progression of T2DM by inhibiting the endoplasmic reticulum stress PERK/ATF4/CHOP signaling pathway,and down-regulating the expressions of related genes and proteins.