转基因荧光小鼠视神经轴索钝性损伤后退行性病变观察

目的 建立单侧眼视神经轴索钝性损伤模型,观察视神经轴突退行性病变过程和小胶质细胞的变化.方法 将标记神经轴突的YFP小鼠和标记小胶质细胞的GFP小鼠分为手术组和正常对照组,并于视神经轴索钝性损伤手术后4h、1d、3d、5d、10d分离视神经,以激光共聚焦显微镜观察神经轴突受损程度及小胶质细胞的变化.结果 与对正常对照组比较,YFP小鼠术后4h损伤处视神经轴突断裂;术后1d视神经轴突开始出现念珠化;术后3d视神经轴突大部分念珠化;术后5d视神经轴突开始从念珠状转变为碎片状;术后10 d视神经轴突形成大量碎片.GFP小鼠与正常对照组相比,术后4h形成胶质瘢痕,静息态小胶质细胞开始大量出现;术后1d激活态小胶质细胞大量增多并开始覆盖受损区域;术后3d大量的激活态小胶质细胞基本覆盖了受损区域;术后5d、10 d虽然视神经的退行性病变持续恶化,但是小胶质细胞的数量基本保持稳定.结论 小鼠视神经受损后轴突发生不可逆的退行性病变,同时并伴随着小胶质细胞的激活和增多,说明小胶质细胞与视神经的退行性病变密切关联.

Neurodegenerative disorder after optic nerve crush in transgenic fluorescence mice

Objective To observe optic nerve axons degenerative disorder and microglial responses by establishing unilateral optic nerve crush model.Methods YFP mouse group with axonal markers and GFP mouse group with microglia markers were divided into surgery and control group,the optic nerve were dissected at 4 hours,1 day,3 days,5 days,10 days after optic nerve crush,and the neuronal degenerative disorder and microglial responses were observed by confocal laser scanning microscope.Rrsults Compared with control group,the optic nerve axons in YFP mouse group were fractured in injury region at postoperative 4 hours;The partial axon became beadlike change at postoperative 1 day;Most of the axons turned into the process of beadlike change at postoperative 3 days;The axons became to debris from beadlike at postoperative 5 days;The axons changed into many debris at postoperative 10 days.Compared with control group,the formation of glial scar and resting microglia in GFP mouse group began to emerge at postoperative 4 hours;The microglia gradually activated and began to cover the injury region at postoperative 1 day;The activated miacroglia basically covered the injury region at postoperative 3 days;The number of microglia roughly remained stable,although the axons continued to deteriorate at postoperative 5 days and 10 days.Conclusion The optic nerve occur irreversible degenerative disorder after being injured,meanwhile with the microglial increase and activation.This phenomenon suggests that microglia is closely associated with optic nerve degeneration.