重组人促红细胞生成素对慢性高眼压致大鼠视网膜神经元损伤的保护作用

目的:探讨玻璃体内注射重组人促红细胞生成素(recombinant human erythropoietin,rHuEPO)对慢性高眼压所致的大鼠视网膜神经元损伤的保护作用及其可能的作用机制。方法:健康SD大鼠30只随机分为5组,每组6只,分别为损伤组I,损伤组Ⅱ、DMSO组、rHuEPO组和rHuEPO+Wortmannin(WM)组。各组均以右眼为实验眼,损伤组Ⅱ大鼠激光处理1d后处死,其余各组激光处理8wk后处死。损伤组用532nm激光烧灼大鼠角巩膜缘浅层静脉,阻断房水回流的方法建立大鼠慢性高眼压模型,采用Tono-pen眼压计测量眼压。DMSO组、rHuEPO组和rHuEPO+WM组大鼠均在激光处理后1d开始分别向玻璃体内注射DM-SO、rHuEPO和rHuEPO+WM,1次/wk。正常对照组选取损伤组左眼作为对照眼。用免疫组织化学法和TUNEL染色检测观察各组实验结果。结果:与正常对照组比较,各组视网膜神经节细胞层(retinal ganglion cell layer,RGCL)中促红细胞生成素受体(erythropoirtin receptor,EPOR)表达增加,差异具有统计学意义(P<0.05)。与正常对照组比较,各组RGCL中蛋白激酶B(AKT)表达无明显改变,差异无统计学意义,损伤组I和DMSO组RGCL中磷酸化蛋白激酶B(PAKT)表达也无明显改变,但rHuEPO组RGCL中PAKT表达增加(P<0.05)。与损伤组I和DMSO组比较,rHuEPO组RGCL中凋亡神经细胞数目减少(P<0.05)。与rHuEPO组比较,rHuEPO+WM组RGCL中AKT表达无明显变化,但PA-KT表达减少(P<0.05),凋亡神经细胞数目增加(P<0.05)。结论:rHuEPO对慢性高眼压所致的大鼠视网膜神经元损伤有保护作用,且rHuEPO通过PI-3K/AKT信号途径抑制神经细胞凋亡而发挥其视神经保护作用。

Neuroprotection of recombinant human erythropoietin on chronic ocular hyperten-sion induced retinal neuron injury in rats

AIM:To evaluate the neuroprotective effect and its possible mechanism of recombinant human erythropoietin (rHuEPO) in chronic ocular hypertension model of Sprague-Dawley (SD) rats. ·METHODS: Thirty healthy SD rats were randomly divided into five groups, which were damaged group I, damaged group Ⅱ, DMSO group, rHuEPO group and rHuEPO+ Wortmannin (WM) group respectively. Each group has six rats, the right eyes were experimental eyes. The rats in damaged group Ⅱ and in other groups were sacrificed in one day and in eight weeks after laser treatment respectively. Chronic ocular hypertension model was induced by episcleral venous occlusion through 532nm laser for rats in damaged group and the Tono-pen was employed to measure intraocular pressure (IOP). DMSO, rHuEPO and rHuEPO+WM were chosen for intravitreal injection for each group, respectively, and intravitreal injection started from the first day after laser treatment and for once each week. The left eye of the damaged group was served as normal group. The change of EPOR, AKT and PAKT expression for each group was characterized in retinal ganglion cell layer (RGCL) by immuneohistochemistry. The amount of neuron apo-ptosis in RGCL was measured by TUNEL staining.·RESULTS: Compared with the normal group, EPOR expression of each group significantly increased after chronic ocular hypertension (P<0.05). Compared with the normal group, AKT expression of each group didn’t change significantly, PAKT expression of the damaged group I and DMSO group either didn’t change significantly, but PAKT expression of rHuEPO group increased remarkably (P<0.05). Compared with the damaged group I and DMSO group, The amount of neuron apoptosis of rHuEPO group decreased obviously (P<0.05). Compared with rHuEPO group, AKT ex-pression didn’t change significantly, PAKT expression decreased remarkably (P<0.05), and the amount of neu-ron apoptosis increased observably (P<0.05) for rHuEPO+ WM group.·CONCLUSION: rHuEPO has neuroprotective effect on chronic ocular hypertension induced retinal neuron injury in SD rats and it is likely that neuroprotective effect were conveyed by activation of the PI-3K/AKT signal pathway.