兔视网膜光损伤模型的建立

Establishment and study of model of retinal photic injury in rabbit

目的建立和研究视网膜光损伤动物模型,观察手术显微镜致兔眼视网膜光损伤的病理变化。方法将健康灰兔8只随机分为对照组、光损伤组,每组4只。所有实验动物均在循环光环境适应7d,光照前暗适应24h。实验前,散大瞳孔至8mm左右。光损伤组光照(14500lux)30min,暗适应30min。光照48h后取材制成超薄切片,电镜观察。对照组散瞳后不予光照,相应时间取材观察。结果对照组视网膜组织结构清楚,细胞形态规整。光损伤组光感受器外节膜盘崩解非常明显,外核层细胞排列紊乱,核固缩。色素上皮层核染色质边集,呈现细胞凋亡的早期改变,线粒体空泡变性。结论手术显微镜(14500lux)可诱导兔视网膜光损伤,病理特点是光感受器的退行性改变。

Objective Retinal photic-injury can cause photoreceptor apoptosis and retinal degeneration and may even lead to irreversible blindness. Our study was to establish the modified animal models for retinal photic-injury and observe the pathological changes of retinal injury induced by light from operating microscope. Methods Eight healthy pigmented rabbits were divided randomly into the control group and photic-injury group and 4 rabbits for each group. The rabbits were exposed to light 12 hours and dark environment 12 hours daily for 7 days and then were given 24 hours of darkness. The pupils of animals were dilated till the diameter of 8 mm before irradiation of light. The rabbits in photic-injury group were given light exposure of 30 minutes（14 500 lux） and sequentially 30 minutes of darkness. After 48 hours, the light injury eyes were enucleated for the histological observation under the electron microscope. The rabbits in the control group were not irradiated. Results No any abnormality of retinal structures was found in the control group. However, in light-exposed group, the arrangement of outer segments of photoreceptor was disorder, and the disorganizations of stack structure of membrane disks and cells of the outer nuclear layer were seen under the electron microscope. The nuclear chromatin margining emerged in purpurogenous membrane, showing some changes of cellular apoptosis. The mitochondria showed the vacuolization. Conclusion The illumination from operating microscope （ 14 500 lux） can result in the photic damage in rabbit retina. The degeneration of photoreceptor is the pathologic characteristic of retinal photic damage.