VEGF对大鼠慢性高眼压视网膜神经节细胞的作用

Effect of vascular endothelium growth factor on the retinal ganglion cells of rats with chronic intraocular hypertension

目的:探讨血管内皮生长因子(vascular endothelium growth factor,VEGF)对大鼠视网膜色素上皮生长因子(pigment epithelium-derived factor,PEDF)表达的影响及VEGF对慢性高眼压条件下神经节细胞(retinal ganglion cells,RGCs)的保护作用和可能途径。方法:雌性SD大鼠30只,随机分为高眼压+VEGF组A(包括A3d,A14d)、高眼压+安慰剂组B(包括B3d,B14d)和正常+VEGF组C(包括C3d,C14d),A、B组模型制作应用巩膜浅层静脉烧烙法建立慢性高眼压模型,C组只剪开球结膜,不烧烙巩膜浅静脉。A、C组在模型建立后即刻用10μL微注射器于大鼠角膜缘后2mm处刺入玻璃体腔,抽出玻璃体2μL,再向玻璃体腔内注射2μL(0.05μg/μL)重组大鼠VEGF,B组同法注入等量的去离子水。在3d和14d后处死动物,取眼球,冰冻切片,免疫组织化学法观察视网膜PEDF的表达,用TUNEL染色检测各组视网膜神经节细胞的凋亡,免疫荧光双标观察PEDF染色阳性的细胞是何细胞。结果:术后眼压明显升高(P<0.05),术后3d和14d的眼压无显著性差异。视网膜PEDF染色阳性细胞,B组多于A组,A组多于C组;TUNEL荧光染色显示VEGF高眼压组RGCs的凋亡明显的少于高眼压组。结论:玻璃体腔注射VEGF可减少高眼压视网膜神经节细胞的凋亡。

AIM： To investigate how vascular endothelium growth factor （VEGF） contributes to the expression of pigment epithelium-derived factor （PEDF） in retina of rats and evaluate the neuroprotection of VEGF for retinal ganglion cells （RGCs） of rats with chronic intraocular hypertesion and it＇s potential approach. METHODS： Thirty female adult Sprague Dawley rats were randomly divided into three groups： elevated intraocular pressure （EIOP） ＋ VEGF （ group A, including A3d, A14d）, EIOP ＋ placebo （group B, including B3d, B14d）, normal ＋ VEGF （group C, including C3d, C14d）. The model of EIOP were established by obstructing episcleral veins in group A and B, only open the bulber conjunctiva without obstructing episcleral veins in group C. In group A and C, shortly after episcleral veins were cauterized, rats were intravitreously injected 2μL VEGF （ concentration ： 0.05w g/w L） at 2.0mm behind the limbus of cornea. To keep the lOP, 21JL vitreous body were drawn out before the intravitreous injection. In group B, 21JL H20 were intravitreously injected. Three days and 14 days later, the animals were sacrificed and the eye balls were cut with cryostat, then TUNEL staining protocol were carried out to detect apoptotic cells and degenerate neurons in the retina. Immunofluorescent double labeling was performed to identify which cells were PEDF-positive cells in the retina. RESULTS： The lOP was obviously increased after the operation（P〈0.05）, there was no significant difference in lOP between 3 days and 14 days after the operation.TUNEL-positive cells and F J-positive cells in retina of chronic intraocular hypertension group were much more than that of normal group. The number of TUNEL- positive cells in retinas of chronic intraocular hypertension＋ VEGF group was reducing. CONCLUSION： Intravitreal administration of VEGF has the effect of reducing the apoptosis of the RGCs in rats with chronic intraocular hypertension.