糖脂毒性对肥胖大鼠β细胞功能和凋亡的影响研究  

Pancreatic β-cell Dysfunction and Apoptosis Induced by Elevated Free Fatty Acids Synergize with Hyperglycemia

作　　者：谭惠文[1] 赵乃倩[1] 余叶蓉[1] 韩丽娜[1] 张祥迅[2] 

机构地区：[1]四川大学华西医院内分泌科,成都610041 [2]四川大学华西医院内分泌代谢研究室,成都610041

出　　处：《四川大学学报（医学版）》2017年第1期71-75,共5页Journal of Sichuan University(Medical Sciences)

基　　金：国家自然科学基金(No.30570874);四川省科技厅科技支撑计划项目(No.2016SZ0058)资助

摘　　要：目的探讨葡萄糖和游离脂肪酸(FFA)联合作用对胰岛β细胞功能与凋亡的影响及病理生理机制。方法Wistar大鼠采用高脂饲料喂养制造胰岛素抵抗模型,取造模成功的肥胖胰岛素抵抗模型大鼠分为4个亚组,生理盐水组(OB-NS组,n=7)、高葡萄糖组(OB-GS组,n=9)、高游离脂肪酸组(OB-FFA组,n=8)和高糖高脂肪酸组(OBFG组,n=9)。另取5只Wistar大鼠采用普通饲料喂养作为正常对照组。采用比色法检测FFA和β-羟丁酸(β-HBA)水平,采用静脉葡萄糖耐量试验(IVGTT)评价胰岛β细胞胰岛素分泌功能,免疫组织化学方法检测β细胞胰岛素储备的能力,并应用原位末端标记法(TUNEL)检测凋亡的β细胞。结果肥胖大鼠葡萄糖输注率(GIR)低于正常对照〔(10.82±1.8mg/kg·min)vs.(25.21±1.7mg/kg·min),P<0.05〕,提示胰岛素抵抗模型成功建立。OB-FG组大鼠糖负荷后胰岛素分泌达峰时间延后且各时点胰岛素水平明显低于NC组和OB-NS组,差异有统计学意义(P<0.05)。糖负荷后5、10、15和20min时,OB-FG组血胰岛素水平也明显较OB-FFA组、OB-GS组降低,胰岛素和血糖比值及胰岛素释放指数也均低于NC组和OB-NS组,差异有统计学意义。免疫组织化学染色示,OB-FG组胰岛素储备在各高脂肥胖亚组中最低,远低于NC组和OB-NS组(P<0.01),OB-GS组和OB-FFA组胰岛素储备与OB-NS组比较也有不同程度降低(P<0.05)。OB-FG组β细胞凋亡率高于NC组和OB-NS组(P<0.01)。结论糖脂联合毒性在引起肥胖大鼠酮体生成显著增加的同时也导致胰岛细胞分泌功能障碍。Objective To analysis the effects of glucoxicity and lipotoxicity on the function and apoptosis of pancreatic β-cells. Methods The levels of circulating glucose and free fat acids （FFAs） were elevated by infusion dextrose and fat emulsion in high-fat obese rats. The insulin resistance model obese rats were divided into four gourp： obese group with saline infusion （OB-NS group, n=7）, obese group with glucose infusion （OB-GS group, n=9）, obese group with Lipid emulsion infusion （OB-FFA group, n=8）, obese group with glucose and lipid emulsion infusion （OB-FG group, n=9）. Five rats fed with general diet were taken as normal group （NC group）.Plasma FFAs and β-hydroxybutyric acid （β-HBA） concentrations were determined by an enzymatic colorimetric method. An intravenous glucose tolerance test （IVGTT） was performed to examine the glucose-stimulated insulin secretion in vivo and immunohistochemical staining to detect the storage volume of insulin. FFA and β-HBA concentrations were measured at baseline and post-infusion. The apoptosis of pancreatic β-cell was detected byin situ end labeling technique （TUNEL）. Results Glucose infusion rate （GIR） of obese rats was significantly lower than that in NC group 〔（10.82±1.8） mg/（kg·min） vs. （25.21±1.7） mg/（kg·min）, P〈0.05〕, confirming insulin resistance rat model successfully established. The insulin secretion peak load time of OB-FG group rats delayed, and the serum insulin level was significantly lower than that of NC group and OB-NS group during IVGTT. The differences were statistically significant （ P〈0.05）. Compared with OB-NS and NC groups, storage volume of insulin of OB-GS group reduced, and β cell apoptosis rate elevated significantly. Conclusion Glucolipotoxicity could induce ketone overproduction, insulin resistance and defective insulin secretion.

关 键 词：糖脂毒性 胰岛β-细胞功能 酮体生成 

分 类 号：R589.2[医药卫生—内分泌]