大鼠视神经损伤视网膜内P38丝裂原活化蛋白激酶活性的表达

目的:动态观察视神经损伤后视网膜中P38丝裂原活化蛋白激酶(MAPK)活性的表达变化和早期细胞凋亡情况。方法:制作大鼠视神经钳夹伤模型后设立对照组、假手术组和视神经夹伤组,应用免疫组化方法及流式细胞仪分别检测视神经损伤后1,6,12,24h;15,30d共6个时间点3组大鼠视网膜中磷酸化(活化)P38MAPK的表达和早期细胞凋亡率,同时对视网膜形态学改变进行观察。结果:视神经损伤诱导视网膜神经节细胞(RGC)严重丧失,损伤后1~15dRGC快速减少,15d后缓慢减少。在正常对照组、假手术组磷酸化P38MAPK表达阴性,视神经损伤后P38MAPK活性的表达于6h检测到表达,逐渐增加至24h阳性表达达高峰,15d表达下降,30d消失,具有统计学意义(P<0.01)。视神经损伤后早期细胞凋亡率逐渐上升,24h达最高8.9%,随后下降。结论:视神经不完全损伤刺激了大鼠视网膜中P38MAPK的活性表达,与早期细胞凋亡率变化相似。P38MAPK通路与视神经损伤诱导的大鼠视网膜RGC凋亡密切相关。

Expression of activated P38MAPK in retina of rat after crushing injury

AIM:To investigate the expression of phosphorylated/activated P38 mitogen-activated protein kinase(MAPK)and the apoptosis of retinal cells in rat retina after partial optic nerve crush.METHODS:Crush injury was unilaterally produced by crushing the optic nerve 2mm behind the eyeball.Expression and cellular localization of the activated forms of P38MAPK were studied in the retina of normal control group,sham-crushing group and crush group on 1,6,12,24 hours,15 and 30 days after injury,respectively.The apoptosis of retinal cells was detected by flow cytometry at the same time point.RESULTS:The number and forms of retinal ganglion cells(RGCs)were normal from 1 to 12 hours after injury,but decreased significantly from 1 day to 15 days in contrast to normal control group and sham-crushing group.Phospho-P38MAPK was detected in retina of crush group but not in normal control group or sham-crushing group.Activated P38MAPK was first detected in retinal ganglion cell layer 6 hours after injury,and increased significantly to peak 24 hours after injury.The staining of Annexin-V/PI showed that the proportion of apoptotic cells increased with time after injury,peaked 24 hours after injury,and decreased from then on.CONCLUSION:Activation of P38MAPK is closely related to apoptosis of retinal cells induced by optic nerve crush in rat retina.P38MAPK pathway may play a key role in apoptosis of RGCs after injury.