摘要
目的探讨非动脉炎性前部缺血性视神经病变（rNAION）模型大鼠视网膜神经节细胞（RGC）死亡及视神经轴突损伤的特点。方法实验研究。应用孟加拉玫瑰红联合激光光动力方法建立大鼠rNAION模型。按随机数字表法将71只SD大鼠分为模型1周组（14只）、模型2周组（14只）、模型4周组（15只）、模型8周组（16只）、正常对照组（12只）。取右眼为实验眼。借助视网膜切片HE染色、经上丘荧光金逆行标记及荧光显微镜照相、视神经半薄切片甲苯胺蓝染色及透射电镜检查，观察rNAION模型建立后1周、2周、4周、8周时大鼠RGC死亡及视神经轴突损伤的情况。采用单因素方差分析比较5组大鼠RGC密度采用Kruskal-wallis检验比较其存活率。结果视网膜切片HE染色示rNAION大鼠RGC丢失，视网膜外层结构无明显变化。正常对照组、模型1周组、2周组、4周组及8周组大鼠实验眼RGC密度[（2 273±219）、（2 075±120）、（1 783±143）、（1 330±169）及（869±301）个/mm2]的差异有统计学意义（F=80.98，P〈0.01）。RGC死亡以上方象限较明显。RGC存活率分别为99.9%±3.4%、91.8%±2.9%、72.6%±5.7%、54.4%±7.0%、37.5%±13.0%。模型1周组与2周组、2周组与4周组、4周组与8周组RGC存活率的差异均有统计学意义（Z=-3.78，P〈0.01；Z=-3.89，P〈0.01；Z=-3.23，P〈0.01）。甲苯胺蓝染色显示缺血损伤1周后，大鼠视神经即有明显轴突丢失，并逐渐进展；轴突损害以视神经中央部为重。电镜下可见1周内即开始出现视神经轴突水肿、部分髓鞘解体；4周后见大量轴突丢失伴明显胶质瘢痕。结论大鼠rNAION模型建立早期RGC死亡相对缓慢并呈区域性，其后进行性加重。rNAION大鼠的RGC死亡相对视神经损伤滞后、持续周期长。
ObjectiveTo investigate the temporal and spatial characteristics of retinal ganglion cell （RGC） death and axon degeneration in the rat model of nonarteritic anterior ischemic optic neuropathy （rNAION）.MethodsExperimental study. The model of rNAION was induced by directly illuminating the optic nerve head with laser, after intravenous infusion with the photosensitizing agent rose Bengal. Seventy-one SD rats were randomly divided into five groups： 1-week （n=14）, 2-week （n=14）, 4-week （n=15） , 8-week （n=16） model group and the normal control group （n=12）. Hematoxylin and eosin （H＆E） staining and morphometric measurement with FG labeling were performed to assess rNAION-indeced histologic changes in the retina at different time points. RGCs were counted on retinal flat mounts in a masked fashion. Semithin sections stained with toluidine blue and transmission electron microscopy were performed to evaluate axonal degeneration. The differences of RGC density among multiple groups were tested with one-way ANOVA while the survival rate of RGC with kruskal-Wallis.ResultsH＆E-stained retina sections of rNAION revealed RGC loss. The density of labeled RGC was （2 273±219） cells/mm2 in the control group, （2 075±120） cells/mm2 in the 1-week group, （1 783±143） cells/mm2 in the 2-week group, （1 330±169） cells/mm2 in the 4-week group and （869±301） cells/mm2 in the 8-week group. There were significant differences between all pairs of groups （F=80.98, P〈0.01）. The impairment of RGC was aggravatedprogressively, which mainly in the upper quadrant. The survival rate of RGC was 99.9%±3.4%, 91.8%±2.9%, 72.6%±5.7%, 54.4%±7.0% and 37.5%±13.0%, respectively. There were significant differences between the 1-week and 2-week group（Z=-3.78, P〈0.01）, the 2-week and 4-week group（Z=-3.89, P〈0.01）, and the 4-week and 8-week group（Z=-3.23, P〈0.01）. Toluidine blue staining of the ON revealed significant demyelination 1 week after ischemic damage. Progressive axonal degeneration existed for several weeks, which mainly affected the central region of the optic nerve with extensive reactive gliosis. Ultrastructural study showed axonal edema and collapsed sheaths in the ischemic optic. Four weeks later, there were extensive axonal loss and severe glial scars.ConclusionsrNAION results in regional and later RGC death. The extended period of RGC death after rNAION induction is much more longer than previously recognized.
作者
王一玮
陈婷
马瑾
钟勇
Wang Yiwei Chen Ting Ma Jin Zhong Yong(Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences ＆ Peking Union Medical College, Beijing 100730, China)
出处
《中华眼科杂志》
CAS
CSCD
北大核心
2016年第12期918-923,共6页
Chinese Journal of Ophthalmology
