目的:观察长期高脂饮食对大鼠胰岛β细胞凋亡影响,探讨氧化应激相关因子及基因表达与β细胞脂性凋亡关系及可能机制.方法:41只SD雄性大鼠随机分为高脂饲料喂养的肥胖组(n=21)和普通饲料喂养的正常对照组(n=20),喂养28周后,检测血浆及胰腺组织中的丙二醛(MDA)、还原型谷胱甘肽(GSH)浓度;静脉葡萄糖耐量试验评价早相胰岛素分泌反应(AIR);TUNEL法观察胰岛β细胞凋亡情况并计数每个胰岛中β细胞凋亡率;采用荧光定量PCR(Real-time PCR)比较两组大鼠胰岛细胞解偶联蛋白-2(UCP-2)mRNA表达的情况.结果:28周时高脂饲养组血浆及胰腺组织中MDA高于正常饲养组(P<0 05),而高脂饲养组血浆及胰腺组织中GSH低于正常饲养组(P<0 01).与基础值比较,高脂饲养组糖负荷后胰岛素增高的幅度低于正常饲养组(3 0倍vs 5 7倍,P<0 05).高脂饲养组1 min后血糖浓度下降缓慢,3、5、10 min血糖水平均高于正常饲养组(P<0 05).高脂饲养组胰岛β细胞凋亡率比正常饲养组增加40 0;(P<0 01).高脂饲养组胰岛细胞UCP-2基因mRNA表达与正常饲养组相比升高22 4;(P<0 01).结论:高脂喂养28周后SD大鼠胰岛β细胞凋亡率明显增加,血浆及胰岛细胞中MDA升高、GSH降低, 而且胰岛细胞UCP-2基因mRNA表达升高,提示氧化应激可能参与了高脂引起的β细胞脂性凋亡.
Objective: To investigate the effect of β cell lipoapoptosis after long term high-fat feeding in rats,and to investigate the relationship between oxidative stress,gene expression and β cell lipoapoptosis. Methods: Forty-one SD male rats were randomly divided into 2 groups:high-fat diet group (HF group) and control group (NC group).At the end of 28 weeks,the levels of malondialdehyde (MDA) and glutamylcysteinylglycine (GSH) in plasma and pancreatic tissue,the early-phase insulin secretion in β cells,the β cell apoptosis (TUNEL technology) and the uncoupling protein 2 (UCP2) gene expression in islets were measured. Results: The concentrations of MDA both in plasma and pancreatic tissue were higher in HF group than those in NC group.In contrast,The contents of GSH both in plasma and pancreatic tissue were lower in HF group.Insulin secretion response to glucose load was significantly decreased in HF group (3 0 fold vs 5 7 fold,P<0.01).Blood glucose levels at 3 min,5 min and 10 min during IVGTT were significantly higher in HF group than those in NC group (P<0.05).The frequency of β cell apoptosis was increased by 40.0; in HF group (P<0.01).The gene expression of UCP2 in islets was increased by 22.4; in HF group (P<0.01). Conclusion: The frequency of β cell apoptosis in high-fat feeding rats is affected by oxidative stress,which results in increasing UCP2 gene expression.
楼大钧;李宏亮;杨文英;萧建中;杜瑞琴;王冰;白秀平;潘琳. 氧化应激与β细胞脂性凋亡关系及机制研究[J]. 浙江大学学报（医学版）, 2009, 38(6): 620-625.