艾塞那肽与胰岛β细胞凋亡的相关性研究

Relationship between Exendin-4 and apoptosis of pancreatic β cells

目的研究胰高血糖素样肽-1类似物艾塞那肽(Exendin-4)抑制胰岛β细胞凋亡的可能机制。方法将大鼠胰岛素瘤RIN-m5f细胞分为对照组、高糖组、高糖+艾塞那肽组3组,分别用含有正常糖(11.1 mmol/L)、间歇性高糖(11.1 mmol/L、33.3 mmol/L交替使用)、间歇性高糖+艾塞那肽(100 nmol/L)的培养基进行细胞培养,连续培养7 d后通过MTT法检测各组细胞活力及Western blotting方法检测各组细胞中内质网应激(endoplasmic reticulum stress,ERS)标志分子(CHOP、BIP)、磷酸化的c-jun氨基末端激酶(p-JNK)、凋亡分子Caspase-3的表达水平。结果对照组胰岛β细胞中CHOP、BIP、p-JNK、Caspase-3表达水平较低;高糖组胰岛β细胞中CHOP、BIP、p-JNK、Caspase-3表达水平较对照组明显升高(P<0.05);高糖+艾塞那肽组胰岛β细胞中CHOP、BIP、p-JNK、Caspase-3表达水平较高糖组则明显降低(P<0.05)。结论长时间间歇性高糖刺激可使胰岛β细胞活力下降,并可诱发RIN-m5f细胞发生ERS,而艾塞那肽则可抑制ERS,并通过调控细胞JNK信号通路来抑制胰岛β细胞凋亡。

Objective To study the possible mechanism of the Exendin-4 inhibiting apoptosis of the pancreaticβcells.Methods The insulinoma cells of mouse(RIN-m5f)were divided into three groups,the control group cultured with normal sugar content(11.1 mmol/L),the high glucose group cultured with fluctuating high glucose(11.1 mmol/L,33.3 mmol/L alternated),the high glucose+Exendin-4 group cultured with fluctuating high glucose and Exendin-4(100 nmol/L),continuously cultured for 7 days with the complete culture medium.Then,the viability of RIN-m5f cells was investigated by MTT method,and Western blotting technique was used to detect the expressions of the molecules(BIP,CHOP)of cell endoplasmic reticulum stress(ERS)and the phosphorylation of c-jun N-terminal kinase(p-JNK),apoptotic molecule Caspase-3.Results Expressions of CHOP,BIP,p-JNK,Caspase-3 proteins were lower in the control group,while they were all significantly increased in the high glucose group(P<0.05).Expressions of CHOP,BIP,p-JNK,Caspase-3 were obviously decreased in the high glucose+Exendin-4 group compared with high glucose group(P<0.05).Conclusion Fluctuating high glucose decreases the activity and induces ERS in RIN-m5f cells,and Exendin-4 may suppress theβ-cell apoptosis by inhibiting ERS and regulating the JNK signaling pathway.