葡萄糖调节蛋白在大鼠视网膜缺血再灌注损伤中的时相性表达及意义

Phase expression of glucose-regulated protein in rat retina induced by ischemic reperfusion injury

目的检测葡萄糖调节蛋白(glucose-regulated protein 78,grp78)在大鼠视网膜缺血再灌注后不同时期的表达情况,探讨内质网应激在视网膜缺血再灌注损伤中的作用及机制。方法36只Wistar大鼠随机分为6组:缺血再灌注6h、12h、24h、48h和72h组,以及正常对照组,每组6只大鼠。缺血组大鼠均行单眼生理盐水前房高压灌注(110mmHg×60min,1kPa=7.5mmHg)的方法建立视网膜缺血再灌注模型,用免疫组织化学和半定量RT-PCR方法检测grp78在视网膜中的定位及时相性表达,取各组平均光密度值进行统计分析。结果grp78在正常大鼠视网膜中少量表达,主要分布于视网膜内核层和神经节细胞层,免疫组织化学和RT-PCR检测均发现在视网膜缺血再灌注后6hgrp78的表达量开始升高(A值为0.778±0.004,与正常对照组0.756±0.007相比P<0.05);再灌注后24h其表达量达到峰值(A值为0.851±0.040),与正常对照组比较P<0.01,与12h组(A值为0.799±0.010)相比P<0.01;再灌注48hgrp78表达开始下降(A值为0.825±0.007,与24h相比P<0.05),但仍高于正常对照组(P<0.01);72h组grp78的表达与正常组相比,差异无统计学意义。结论grp78参与了大鼠视网膜缺血再灌注损伤机制,若能在损伤早期内质网应激环节上加以干预,可为临床治疗和干预提供一定的理论依据。

Objective To observe the expression of glucose-regulated protein 78 （grp78） in the rat retina induced by ischemic reperfusion injury,and investigate the possible effect of endoplasmic reticulum stress in the ischemic process.Methods Thirty-six wistar rats were equally divided into 6 groups randomly：normal control group and 6 hours,12 hours,24 hours,48 hours and 72 hours after ischemic reperfusion groups,6 rats in each group.The rat retinal ischemia reperfusion model was established by acute elevated intraocular pressure through normal saline intracameral perfusion（110 mmHg×60 min,1 kPa=7.5 mmHg）.The expression of grp78 in rats retina was detected by immunohistochemistry and semiquantitative RT-PCR methods at the different time points.The average optical density was statistically analyzed by SPSS software.Results The expression of grp78 was mainly located in retinal ganglion cell layer and inner nuclear layer.The expression of grp78 began to increase and augmented gradually at 6 hours（A：0.778±0.004） after reperfusion compare with control（A：0.756±0.007）（P〈0.05）.The highest level of expression was reached at 24 hours（A：0.851±0.040） after reperfusion comparing with hour 12（A：0.799±0.010）（P〈0.01）.The level then began to decrease at hour 48（A：0.825±0.007） comparing with hour 24（P〈0.05）,but still higher than control（P〈0.01）.There was no significant grp78 expression between hour 72 and control.Conclusion Grp78 participate the process of retina ischemic reperfusion injury.It can provide theoretical data for clinical treatment,if we interfere endoplasmic reticulum stress at the early stage.