小胶质细胞活化与rd小鼠遗传性视网膜变性

目的研究小胶质细胞活化与rd小鼠遗传性视网膜变性的关系。方法对出生后8、10、12、14、16及18d的rd小鼠及对照小鼠视网膜进行感光细胞凋亡TUNEL法检测及形态计量学分析。CD11b免疫组织化学染色标记视网膜小胶质细胞。结果rd小鼠出生后10d视网膜感光细胞层开始出现TUNEL染色阳性细胞,第16d达到高峰。视网膜小胶质细胞在rd小鼠出生后10d开始活化,第14d达到高峰。小胶质细胞向感光细胞层的迁移与感光细胞凋亡之间存在紧密的时间和空间关系。结论rd小鼠视网膜变性以感光细胞凋亡为主。小胶质细胞活化可能在视网膜变性过程中发挥重要作用。

Activation of microglia in the inherited retinal dystrophy of rd mice

ObjectiveTo study the relationship between activation of microglia and photoreceptor apoptosis in the rd mice.MethodsPhotoreceptor apoptosis in the rd mice at postnatal day 8,10,12,14,16 and 18 was detected by TUNEL assay.CD11b antibody was used to label retinal microglia.ResultsTUNEL assay demonstrated that positive cells began to emerge in the outer nuclear layer(ONL) of retina at 10 postnatal days and reached a peak at 16 postnatal days in the rd mice.Immunohistochemical labeling of retinal microglia showed that CD11b-labled cells were restricted to the inner retinal layers in the normal retina.However,CD11b-labled cells began to increase and migrate to the inner portion of the ONL in the rd retina at 10 postnatal days and infiltrated the entire ONL and subretinal space at 14 postnatal days. By 18 postnatal days,only a few CD11b-labled cells scattered among the remaining photoreceptor cells.These results suggested that photoreceptor apoptosis started at 10 postnatal days and got a peak at 16 postnatal days,and activition of microglia was observed at 10 postnatal days and reached a top level at 14 postnatal days. A close temporal and spatial relationship between migration of microglial cells toward the photoreceptor cell layer and progression of photoreceptor degeneration was noted.ConclusionPhotoreceptor cell death in the rd retina occur through apoptosis.Activation of microglia may play an important role in the retinal dystrophy of rd mice.