大剂量甲基泼尼松龙对大鼠视神经挤压伤后RGC凋亡的影响

目的　观察大剂量甲基泼尼松龙 (MP)对大鼠视神经挤压伤后视网膜神经节细胞 (RGC)凋亡的影响。方法　大鼠 12 6只分为正常对照组 18只 3 6眼、损伤组 54只 54眼和MP治疗组 54只 54眼。伤后 4、7和 14d ,通过视网膜铺片和切片相结合的技术 ,进行细胞原位凋亡检测以及Bcl 2和Bax阳性细胞计数 (免疫组化SP法 )。结果　正常对照组有少量凋亡细胞 ,Bcl 2和Bax阳性细胞数少 ;伤后 4、7、14d凋亡细胞大量增加 ,治疗组凋亡细胞各时间点均低于损伤组 ,差异有显著性 (P <0 0 5) ;治疗组Bcl 2阳性细胞数各时间点均高于损伤组 ,Bax阳性细胞数均低于损伤组 ,差异有显著性 (P <0 0 5)。结论　大剂量MP能抑制视神经挫伤后RGC的凋亡 ,上调bcl 2基因的表达和下调bax基因的表达可能是MP治疗作用机制之一

Effect of high dosage of methylprednisolone on retinal ganglion cell apoptosis after optic nerve crush of rat

ObjectiveTo investigate the effect of high dose methylpredni so lone(MP) on retinal ganglion cells(RGC) apoptosis.MethodsOne hundred and twe nty six Wistar rats were divided into normal control,crush and MP treatment grou ps.Apoptotic cells,Bcl-2 and Bax positive cells were located and calculated by terminal-deoxynucleotidyl transferase mediated dUTP-biotin nick end labeling ( TUNEL),immunohistochemical method and retinal whole-mount combined with section technique at day 4,7,and 14 after crush,respectively.ResultsFew apoptotic c ells,a few of Bcl-2 and Bax positive cells were observed in normal control grou ps.The number of positive cells increased gradually after crush.The number of ap optotic cells and bax positive cells in treatment groups were less than those in crush group significantly( P <0.05),while the number of bcl-2 positive ce lls in treatment group were more than those in crush group at day 4,7,and 14 aft er crush significantly( P <0.05).ConclusionHigh dosage of MP inhibits R GC apoptosis through up-regulation of bcl-2 gene expression and down-regulati on of bax gene expression.