Raf-1激酶抑制蛋白(RKIP)对糖尿病大鼠视网膜神经损伤的保护作用

目的　探讨Raf-1激酶抑制蛋白(raf-1 kinase inhibitory protein,RKIP)通过p38-MAPK通路对糖尿病(DM)大鼠视网膜神经损伤的保护作用。方法　雄性SD大鼠48只，采用随机数字表法将大鼠分为对照组、空白组、糖尿病组、RKIP组，每组12只;空白组、糖尿病组和RKIP组大鼠腹腔注射链脲佐菌素建立DM模型。RKIP组和空白组于模型建成第2周玻璃体内分别注射携带RKIP基因片段重组慢病毒(LV-RKIP)和等量空白病毒，对照组和糖尿病组注射等量生理盐水。注射10周后利用Western blot和免疫荧光化学检测各组RKIP、p38丝裂原激活蛋白激酶(p38-mitogen-activated protein kinase,p38-MAPK) 、胶质细胞谷氨酸转运体(L-glutamate/L-asparate transporter,GLAST)和谷氨酰胺合成酶(glutamine synthetase,GS)在视网膜中的表达，HE染色检测各组视网膜神经节细胞(retinal ganglion cell,RGC)密度。结果　与对照组相比，糖尿病组p38-MAPK表达升高，RKIP、GLAST、GS表达下降，RGC密度减少(均为P<0.01)；与糖尿病组相比，空白组各指标差异均无统计学意义(均为P>0.05)，RKIP组p38-MAPK表达降低，RKIP、GLAST、GS表达升高，RGC密度增多(均为P<0.01)。结论　糖尿病视网膜病变早期注射RKIP可降低视网膜细胞中p38-MAPK表达量，提高GLAST、GS表达活性，改善Müller细胞功能，减少RGC损害，提示RKIP对糖尿病视网膜病变中视网膜神经细胞具有保护作用。

Protective effect of RKIP on retinal nerve injury in diabetic rats through p38-MAPK pathway

Objective To investigate the protective effect of Raf-1 kinase inhibitory protein(RKIP)on retinal nerve injury in diabetes mellitus(DM)rats through p38-MAPK pathway.Methods Forty-eight male Sprague-Dawley(SD)rats were divided into the control group,blank group,DM group and RKIP group by random number table method,12 rats in each group.Streptozotocin was intraperitoneally injected into the rats in blank,DM and RKIP groups to establish DM models.In the second week after successful model establishment,rats in RKIP group and blank group received intravitreous injection of recombinant lentivirus containing RKIP gene fragment(LV-RKIP)and blank virus,respectively,rats in control group and DM group received injection of equivalent normal saline.After 10 weeks,Western blot and immunofluorescence chemical method were adopted to detect the expression of RKIP,p38-Mitogen-activated protein kinase(p38-MAPK),L-glutamate/L-asparate transporter(GLAST)and glutamine synthetase(GS)in the retina of rats in each group.HE staining was used to detect the density of retinal ganglion cells(RGC).Results Compared with the control group,p38-MAPK expression increased,the expression of RKIP,GLAST and GS decreased,and the density of RGC decreased in DM group(all P<0.01).Compared with the DM group,the blank group had no statistical significance in each index(all P>0.05);p38-MAPK expression decreased,the expression of RKIP,GLAST and GS increased,and the density of RGC increased in PKIP group(all P<0.01).Conclusion Early administration of RKIP can reduce the expression of p38-MAPK in retinal cells,increase the expression activity of GLAST and GS,improve the function of Müller cells,and reduce the damage of RGC for rats with diabetic retinopathy,indicating that RKIP has a protective effect on retinal neurons..