胃饥饿素通过抑制内质网应激减少高糖诱导的视网膜血管内皮细胞凋亡

Ghrelin attenuates high glucose-induced apoptosis of retinal vascular endothelial cells by inhibiting endoplasmic reticulum stress

目的研究胃饥饿素(ghrelin)对内质网应激及高浓度葡萄糖导致的人视网膜血管内皮细胞(HRMECs)凋亡的影响。方法将HRMECs细胞分为对照组、高糖组、高糖+ghrelin组和高糖+ghrelin+衣霉素(内质网应激诱导剂)组。对照组细胞不加干预,高糖组采用30 mmol/L葡萄糖构建细胞损伤模型,高糖+ghrelin组采用30 mmol/L葡萄糖和10 nmol/L ghrelin处理细胞,高糖+ghrelin+衣霉素组采用30 mmol/L葡萄糖、10 nmol/L ghrelin和10μmol/L衣霉素联合处理细胞,所有细胞均培养48 h。采用AnnexinⅤ-FITC/7-AAD试剂盒检测4组细胞凋亡率,蛋白质印迹法检测对照组、高糖组和高糖+ghrelin组细胞凋亡蛋白Bax、Bcl-2及内质网应激蛋白GPR78、IRE1α的表达。结果与对照组比较,高糖组HRMECs细胞凋亡率明显升高(P<0.05);与高糖组相比,高糖+ghrelin组细胞凋亡率明显降低(P<0.05)。与对照组比较,高糖组细胞Bax、GPR78及p-IRE1α的蛋白表达明显增加(均P<0.05),Bcl-2的表达明显降低(P<0.05);与高糖组相比,高糖+ghrelin组细胞Bax、GPR78及p-IRE1α的蛋白表达均明显降低(均P<0.05),Bcl-2的表达明显升高(P<0.05)。与高糖+ghrelin组相比,高糖+ghrelin+衣霉素组的细胞凋亡率明显升高(P<0.05)。结论Ghrelin可以减少高糖诱导的视网膜血管内皮细胞凋亡,其机制可能与ghrelin抑制激活的内质网应激有关。

Objective To investigate the effects of ghrelin on endoplasmic reticulum stress(ERS) and apoptosis of human retinal vascular endothelial cells(HRMECs) induced by high concentration of glucose.Methods HRMECs were divided into control group,high glucose group,high glucose+ghrelin group,and high glucose+ghrelin+tunicamycin(an inducer of ER stress) group.Cells in control group were treated without any intervention.Cells in high glucose group were treated with 30 mmol/L glucose to establish the cell injury model.Cells in high glucose+ghrelin group were treated with 30 mmol/L glucose and 10 nmol/L ghrelin.Cells in high glucose+ghrelin+tunicamycin group were treated with 30 mmol/L glucose,10 nmol/L ghrelin and 10 μmol/L tunicamycin.Annexin Ⅴ-FITC/PI kit was used to detect the cell apoptosis in the four groups.Western blot was used to detect the expressions of apoptosis proteins Bax and Bcl-2,GPR78 and IRE1α in control group,high glucose group,high glucose+ghrelin group.Results The apoptosis rate of HRMECs cells in high glucose group was significantly higher than that in control group(P<0.05),and the apoptosis rate was lower in high glucose+ghrelin group than that in high glucose group(P<0.05).The protein expressions of Bax,GPR78 and p-IRE1α in high glucose group were significantly increased compared with control group(P<0.05),while the expression of Bcl-2 was significantly decreased(P<0.05).Compared with high glucose group,the protein expressions of Bax,GPR78 and p-IRE1α were significantly decreased in high glucose+ghrelin group(P<0.05),while the expression of Bcl-2 was significantly increased(P<0.05).Compared with high glucose+ghrelin group,the apoptosis rate in high glucose+ghrelin+tunicamycin group was significantly increased(P<0.05).Conclusion Ghrelin can alleviate the apoptosis of retinal vascular endothelial cells induced by high glucose,which may be related to the inhibitory effect of ghrelin on activated ERS.