Mas受体激动剂激活RAS非经典通路对db/db糖尿病小鼠胰岛α细胞功能的影响  

Effect of Mas receptor agonist activation on pancreaticαcell function of diabetic db/db mice by RAS non-classical pathway

作　　者：张珍[1] 云鹏 柳丹 刘春燕[2] 黄辛炜 汤嘉豪 胡丹[1] 李芳萍[1] ZHANG Zhen;YUN Peng;LIU Dan;LIU Chun-yan;HUANG Xin-wei;TANG Jia-hao;HU Dan;LIFang-ping(Department of Endocrinology,The Seventh Affiliated Hospital,Sun Yat-sen University,Shenzhen 518107,Guangdong,China;Department of Endocrinology,Affiliated Hospital of Jiangnan University,Wuxi 214035,Jiangsu,China)

机构地区：[1]中山大学附属第七医院内分泌科,深圳518107 [2]江南大学附属医院内分泌科,无锡214035

出　　处：《医学研究生学报》2019年第10期1031-1036,共6页Journal of Medical Postgraduates

摘　　要：目的血肾素血管紧张素系统(RAS)的非经典通路对胰岛功能具有重要调控作用,但其对胰高血糖素分泌的影响仍未知。文中探讨Mas受体激动剂AVE0991对db/db糖尿病小鼠胰岛α细胞胰高血糖素分泌的影响及可能机制。方法30只db/db糖尿病小鼠随机数字表法分为AVE组和模型组,每组15只,分别给予20 mg/(kg·d)的AVE0991及安慰剂灌胃,15只同周龄db/m小鼠作为正常组给予安慰剂灌胃。每周监测体重、血糖等生化指标,6周后行腹腔葡萄糖耐量试验及体外胰岛灌流评估胰高血糖素分泌功能,取胰腺行免疫组化分析胰岛α及β细胞含量,并采用RT-PCR及Western blot方法检测胰岛内葡萄糖激酶(GCK)的表达。结果干预6周后,AVE组小鼠空腹血糖[(19.1±0.8)mmol/L]、空腹胰岛素水平[(14.1±0.5)mU/L]均明显低于模型组[(25.3±3.0)mmol/L、(17.3±1.8)mU/L],差异有统计学意义(P<0.05),但高于正常组[(6.3±0.5)mmol/L、(5.7±0.3)mU/L],差异有统计学意义(P<0.05)。在糖负荷后30、60和120 min,AVE组血糖值和胰高血糖素水平均低于模型组,但仍高于正常组(P<0.05)。低糖灌流时,正常组小鼠胰岛的胰高血糖素分泌水平[(20.6±0.5)pmol/L]低于模型组[(29.1±0.7)pmol/L]及AVE组[(27.6±0.8)pmol/L],差异有统计学意义(P<0.05)。高糖灌流时,与模型组比较,AVE组高糖灌流30、60 min高血糖素水平差异均有统计学意义(P<0.05)。半定量分析表明模型组胰岛α细胞含量[(3.3±0.7)mg]较正常组[(1.2±0.3)mg]明显升高(P<0.05),β细胞含量[(2.4±0.6)mg]较正常组[(4.8±0.3)mg]明显降低(P<0.05);与模型组相比,AVE组胰岛α细胞含量[(1.8±0.4)mg]降低(P<0.05),β细胞含量[(4.2±0.5)mg]升高(P<0.05)。模型组胰岛GCK mRNA及蛋白的表达均低于正常组(P<0.05);与模型组比较,AVE组GCK mRNA及蛋白表达升高(P<0.05)。结论激活Mas受体可通过降低db/db糖尿病小鼠糖负荷后胰高血糖素的分泌水平改善糖代谢,其机制可能与降低胰岛αObjective The imbalance of glucagon secretion plays an important role in the development of diabetes.The newly discovered ACE2/Ang(1-7)/Mas pathway is an vital branch of the RAS system and has regulatory effects on islet function,but its effect on glucagon secretion is still unknown.The article aimed to investigate the effect and possible mechanisms of AVE0991,a Mas receptor agonist on glucagon secretion of diabetic db/db mice.Methods A tolal of 30 db/db mice were randomized to AVE group and model group(n=15),and their age-matched nondiabetic db/m mice were selected as the normal group(n=15).The mice in AVE group were treated with AVE0991 20mg/kg/d and those in model group were treated with placebo via gavage for 6 weeks.The metabolic indicators were measured every week.After 6 weeks of treatment,intraperitoneal glucose tolerance test(IPGTT)and islet perifusion were performed to evaluate glucagon release kinetics in vivo and vitro.Double-label immunofluoresence assay was adoppted to assess the content ofαandβcells.Moreover,qRT-PCR and western blot were employed to detect the GCK expression in islets.Results The fasting blood sugar[(19.1±0.8)mmol/L]and glucose tolerance[(14.1±0.5)mU/L]of AVE group were significantly lower than those of the model group[(25.3±3.0)mmol/L,(17.3±1.8)mU/L](P<0.05)and still higher than those of normal group[(6.3±0.5)mmol/L,(5.7±0.3)mU/L](P<0.05).At the 30,60,and 120 min after IPGTT,the blood glucose level and glucagon level in AVE group were lower than model group,but still higher than the normal group(P<0.05).During low glucose perfusion,the glucagon secretion level of the islets of normal group[(20.6±0.5 pmol/L)]was lower than that of model group[(29.1±0.7)pmol/L)]and AVE group[(27.6±0.8)Pmol/L],and the difference was statistically significant(P<0.05).During high glucose perfusion,there was a statistically significant difference in glucagon level between AVE group and model group at 30 and 60 min(P<0.05).Semi-quantitative analysis showed that the isletα-cell content of mode

关 键 词：MAS受体 胰岛Α细胞 葡萄糖激酶 糖尿病 

分 类 号：R587.1[医药卫生—内分泌]