胶质纤维酸性蛋白在青光眼大鼠视网膜神经胶质细胞中的表达

目的:探讨胶质纤维酸性蛋白(GFAP)在青光眼大鼠视网膜Müler细胞上的诱导表达情况及可能的意义。方法:采用烧灼涡静脉的方法制作大鼠青光眼模型,分别于术后2h;1,3d;1,2,3wk取材,制作视网膜矢状位冰冻切片和视网膜铺片,进行GS/GFAP免疫荧光双标。提取视网膜总蛋白行GFAP免疫印迹半定量分析。结果:视网膜矢状位切片可见,正常大鼠视网膜中,GFAP阳性染色只出现在神经节细胞层的星形胶质细胞上,而Müller细胞不表达GFAP。制作青光眼模型术后2h,Müller细胞上出现GFAP阳性染色,术后1,3d,GFAP的表达显著增加,到术后1wk,GFAP在Müller细胞上的表达量达到高峰,一直持续到术后3wk,免疫印迹半定量分析与以上结果吻合。术后1wk视网膜铺片中清晰可见Müller细胞足板出现GFAP的诱导表达。结论:高眼压时GFAP在Müller细胞上的诱导表达尤其在足板处的强烈表达是Müller细胞对眼压升高产生的一种反应,GFAP可能是一种潜在的有用的生物标记物。

Expression of glial fibrillary acidic protein in retinal Müller cells of rats with glaucoma

AIM:To explore the induced expression of glial fibrillary acidic protein(GFAP)in rat retinal Müller cells subjected to experimentally induced glaucoma.METHODS:Cauterization of the limbus-draining veins was used to induce glaucoma.Three rats were killed at each of the points at postoperative 2 hours,1 and 3 days and 1,2 and 3 weeks respectively for sagittal retinal sections.Double immunofluorescence was carried out between glutamine synthetase(GS)and GFAP antiserum.Sections were examined under an Olympus confocal laser scaning microcope FV1000.RESULTS:In normal condition there was no expression of GFAP in Müller cells.Müller glial cells reacted vigorously to increased intraocular pressure(IOP)as manifested by the induced and upregulated expression of GFAP.The induced expression of GFAP with the rise of IOP began at postoperative 2 hours.The marked GFAP expression appeared to be most intense at postoperative 1 week and was sustained at postoperative 3 weeks.Induced GFAP expression in Müller glial cells was demonstrated unequivocally in whole-mount preparation of the retina.Western blotting analysis confirmed a marked increase in expression of GFAP after operation.CONCLUSION:GFAP is a potential and useful biomarker for retina injury.The induced expression of nestin in Müller glial cells,especially at their end-feet,suggests a potential neuroprotective mechanism in neuronal degeneration.