高糖刺激人视网膜色素上皮细胞诱导型一氧化氮合酶表达及与p38 MAPK信号通路关系

目的:观察高糖刺激体外培养的人视网膜色素上皮(human retinal pigment epithelium,RPE)细胞表达诱导型一氧化氮合酶(inducible nitric oxide synthase,iNOS)的作用及其与p38信号通路(p38 mitogen activated protein kinase,p38 MAPK)的关系,从而进一步探讨糖尿病视网膜病变的发病机制.方法:培养人RPE细胞,分为对照组、高糖组、高糖 SB203580组和甘露醇组,采用四甲基氮唑蓝(MTT)比色法检测细胞活力,免疫荧光染色法观察RPE细胞中磷酸化p38 MAPK和iNOS的蛋白表达.结果:①MTT检测结果:高糖可以抑制RPE细胞增殖,加入特异性p38 MAPK抑制剂SB203580预处理后,抑制作用减弱;②免疫荧光法检测结果:与对照组相比,高糖组磷酸化p38 MAPK,iNOS蛋白表达明显增高;加入SB203580预处理后,iNOS表达被显著抑制.结论:高糖能够抑制RPE细胞增殖,通过活化p38 MAPK信号通路刺激RPE细胞iNOS的表达,在糖尿病视网膜病变的发生发展中起重要作用.

High glucose induce production of iNOS by human retinal pigment epithelium cells through activation of the p38 signal pathway

Objective:To study the changes of inducible nitric oxide synthase expression induced by high glucose treatment and the relationship between p38 mitogen activated protein kinase and the level of iNOS expression in human retinal pigment epithelium cells. Methods:The cells were divided into control group, high glucose group, high glucose plus SB203580 group and mannitol group. Cell viability was assessed by the MTT assay. The changes of iNOS and p-p38 MAPK expressed by RPE cells were studied with immunofluorescence staining method in a qualitative way. Results:(1) The treatment of RPE cells with 33 mmol/L glucose caused an obviously decrease of cellular viability. After pretreated with SB203580, cell viability was elevated compare with high glucose group. (2)iNOS expression and the phosphorylation level of p38 MAPK were enhanced obviously by high concentration glucose. After pretreated by SB203580, the high glucose-evoked iNOS expression was significantly inhibited. Conclusion:High glucose could inhibits RPE cells proliferation. RPE cells cultured with high glucose could enhance expression of iNOS of the cells in vitro, at least in part, by activation of p38 MAPK pathway. It suggested that RPE cells under the effecting of high glucose might participate in the pathological reaction of diabetic retinopathy.