细胞凋亡和线粒体凋亡途径在糖脂毒性导致胰岛β细胞功能衰竭中的作用  

Role of apoptosis and mitochondrial apoptotic pathway in glucolipotoxicity-induced islet β-cell dysfunction

作　　者：赵乃倩[1] 余叶蓉[1] 谭惠文[1] 邓刚[1] 张祥迅[1] 

机构地区：[1]四川大学华西医院内分泌科,四川成都610041

出　　处：《南方医科大学学报》2008年第11期2009-2013,共5页Journal of Southern Medical University

摘　　要：目的探讨糖脂毒性引起高脂肥胖大鼠胰岛β细胞功能障碍的可能机制。方法将高脂肥胖雄性Wistar大鼠18只分为3组。对照组6只经颈静脉插管输入生理盐水;高游离脂肪酸组(FFA组)6只输入脂肪乳+肝素;高糖高FFA组(GS-FFA组)6只输入葡萄糖液及脂肪乳+肝素。输注持续时间48h。于输液前及输液结束时经颈动脉采血测定血β-羟丁酸(β-HBA)水平。输液结束后,采用静脉葡萄糖耐量试验(IVGTT)评价3组动物胰岛β细胞分泌功能。IVGTT后处死动物,留取胰尾组织病理标本,采用TUNEL技术检测胰岛细胞凋亡水平,采用免疫组化技术测定胰岛细胞CytC、凋亡诱导因子、caspase-9和caspase-3表达水平。结果(1)静脉输液结束时,3组大鼠血β-HBA水平均较基础值升高,其中GS-FFA组血β-HBA生成显著增加(P<0.05)。(2)GS-FFA组大鼠IVGTT时胰岛素分泌指数(ΔI/ΔG)较对照组、FFA组明显减低(P<0.05)。(3)3组大鼠中,GS-FFA组胰岛细胞凋亡比例显著增加(P<0.05),同时GS-FFA组胰岛细胞CytC、凋亡诱导因子、caspase-9及caspase-3表达水平显著增高(P<0.05)。结论高血糖与高FFA血症协同作用可严重损害高脂肥胖大鼠胰岛β细胞的胰岛素分泌功能,导致酮体生成显著增加。糖脂毒性严重损害高脂肥胖大鼠胰岛素分泌功能的机制与胰岛β细胞凋亡显著增加及激活线粒体凋亡途径有关。Objective To investigate the mechanism of β-cell dysfimction induced by glucolipotoxicity in high fat-fed obese rats. Methods Eighteen high-fat obese male Wistar rats were assigned into 3 groups and underwent 48-hour infusion through the jugular vein with normal saline （n=6）, 20% intralipid ＋ heparin （FFA group, n=6）, or 25%glucose ＋20% intralipid ＋ heparin （GS-FFA group, n=6）. The plasma β-hydroxybutyric acid （β-HBA） was measured before and at the end of the infusion. After the infusion, the rats were sacrificed following an intravenous glucose tolerance test （IVGTT） to remove the tail of the pancreas for detection of apoptotic islet cells using TUNEL method. Immunohistochemical staining was performed to detect the expression of cytochrome c （cyt c）, apoptosis-inducing factor （AIF）, caspase-9 and caspase-3 in the islet cells. Results At the end of the infusion, all the rats exhibited increased plasma β-HBA levels, which was the highest in the GS-FFA group （P〈0.05）. IVGTT performed after the infusion showed a significantly lower insulinogenic index in GS-FFA group than that in NS and FFA groups. Greater number of apoptotic islet cells was found in the GS-FFA group than in the FFA and NS groups （P〈0.05）, and the islets had significantly higher levels ofcyt c, AIF, caspase-9 and caspase-3 in the former group than in the latter two groups （P〈0.05）. Conclusions Hyperglycemia and high free fatty acid level synergistically impair insulin secretions to cause ketone overproduction in high fat-fed obese rats. The β-cell dysfimction due to glucolipotoxicity is associated with increased β-cell apoptosis and activation of mitochondrial apoptotic pathway.

关 键 词：糖脂毒性 胰岛细胞凋亡 细胞色素C 凋亡诱导因子 CASPASE-9 caspase-3 

分 类 号：R587.1[医药卫生—内分泌] R589.2[医药卫生—内科学]