粉葛水提物对2型糖尿病db/db小鼠胰岛细胞炎症损伤的改善作用及其机制

Ameliorating Effect and Mechanism of Puerariae thomsonii Radix Aqueous Extract on Inflammatory Damage of Islet Cells in Type 2 Diabetic db/db Mice

为探讨粉葛水提物对2型糖尿病db/db小鼠胰岛细胞炎症损伤的作用及机制,将30只db/db小鼠随机分为模型组、粉葛水提物高、中、低剂量组和二甲双胍组,正常组则采用6只db/m小鼠。持续给药8周后,测量小鼠体质量变化、计算胰重比、检测血清空腹胰岛素(fasting serum lisulin,FINS)、血清空腹血糖(fasting blood glucose,FBG)、糖化血清蛋白(glycosylated serum protein,GSP),计算胰岛素抵抗指数(homeostasis model assess-ment for insulin resistance,HOMA-IR);苏木素-伊红(hematoxylin-eosin,HE)染色观察胰腺组织病理学变化;免疫组化(immunohistochemistry,IHC)法检测胰岛细胞中肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、核因子-κBp65(nuclear factor kappa-Bp65,NF-κBp65)和白细胞介素18(interleukin-18,IL-18)的蛋白表达;蛋白免疫印迹(Western blot,WB)法检测胰腺组织寡聚化结构域样受体蛋白3(NOD-like receptor protein 3,NLRP3)、凋亡相关斑点样蛋白(apoptosis-associated speck-like protein,ASC)、半胱氨酸天冬氨酸蛋白水解酶1(cystein-asparate protease 1,caspase-1)、白细胞介素1β(interle-ukin-1β,IL-1β)、IL-18的蛋白表达;免疫荧光(immunofluorescence,IF)法检测胰腺组织NLRP3的表达。结果表明:与正常组比较,模型组小鼠体质量、胰重比、血清GSP、FBG、FINS含量、HOMA-IR水平明显增加;胰岛细胞变形,出现炎性浸润,胰岛细胞和腺泡细胞边界不清晰,TNF-α、NF-κBp65和IL-18的蛋白表达量明显增加;胰腺组织中相关蛋白表达量明显升高。与模型组比较,二甲双胍和粉葛水提物组体质量、胰重比、血清GSP、FBG、FINS明显降低;胰岛细胞形态完整且边界清晰,炎性浸润明显降低,可见较多胰岛细胞,TNF-α、NF-κBp65和IL-18的蛋白表达量明显减少;胰腺组织中相关蛋白表达量明显降低。综上,粉葛水提物可以减轻db/db小鼠胰岛细胞的炎症损伤,降低胰岛素抵抗,改善2型糖尿病症状。其作用机制可能与抑制NLRP3炎性小体通路及其下游炎症因子IL-1β和IL-18的分泌有关。

This paper examined the impact and mechanism of aqueous extract of Puerariae thomsonii Radix(PTR)on inflammatory damage of islet cells in type 2 diabetic db/db mice.Six db/m mice were selected as the normal group and thirty db/db mice were randomly assigned to the model group,high-,medium-,low-dose PTR aqueous extract groups,and metformin group.Eight weeks after administration,the change in body weight of the mice,the pancreas-to-weight ratio,fasting serum insulin(FINS),fasting blood glucose(FBG),glyco-sylated serum protein(GSP),and homeostasis model assessment for insulin resistance(HOMA-IR)were de-termined.Hematoxylin-eosin(HE)staining was used to observe the histopathological changes in pancreas.The protein expressions of tumor necrosis factor-α(TNF-α),nuclear factor kappa-Bp65(NF-κBp65)and in-terleukin-18(IL-18)in islet cells were detected by immunohistochemistry(IHC).Western blot was con-ducted to identify the expressions of NOD-like receptor thermoprotein domain 3(NLRP3),apoptosis-associated speck-like protein containing a caspase recruitment domain(ASC),cystein-asparate protease 1(caspase-1),interleukin-1β(IL-1β),and IL-18 in pancreatic tissue,and the expression of NLRP3 was observed by immu-nofluorescence(IF).The results showed that,compared with the normal group,the model group had in-creased body weight,pancreas-to-weight ratio,GSP,FBG,FINS,and HOMA-IR,distorted and inflammatory-infiltrated islet cells,and unclear boundary between islet cells and acinus cells.There was a significant rise in the protein expressions of TNF-α,NF-κBp65 and IL-18,and the expression of related proteins in pancreatic tissue was markedly elevated.Compared with the conditions in the model group,the body weight,pancreas-to-weight ratio,GSP,FBG,and FINS were significantly lowered in the metformin group and PTR aqueous ex-tract groups.Additionally,more islet cells were intact,with obvious boundaries and greatly reduced inflamma-tory infiltration,and the protein expressions of TNF-α,NF-κBp65,and IL-18 as well as the expression of re-lated proteins in pancreatic tissue dropped in the administration groups compared with those in the model group.In conclusion,PTR aqueous extract can lessen the inflammatory damage of islet cells,decrease insulin resistance,and alleviate the symptoms of type 2 diabetes mellitus.The mechanism may be related to the sup-pression of the NLRP3 inflammasome pathway and the release of the downstream inflammatory cytokines IL-1βand IL-18.