色素上皮衍生因子对大鼠急性视神经损伤超微结构的影响

Effect of pigment epithelium derived factor on ultra structure of acute optic nerve injury in rats

目的探讨色素上皮衍生因子(PEDF)对大鼠视神经急性损伤后视网膜神经节细胞(RGCs)轴突线粒体超微结构的保护作用。方法选取健康雌性SD大鼠60只随机分为三组:空白组、模型组和实验组,每组各20只,空白组不做任何处理,模型组和实验组均采用视神经钳夹法用反向镊钳夹左眼视神经造成视神经不全损伤,右眼不予处理。模型组和实验组左眼造模后即刻、1周、2周分3次分别向玻璃体腔注射平衡盐溶液5μL和PEDF1μg。三组大鼠均在第3周时取材,分别取10只大鼠左眼眼球制作标本,电镜下观察视网膜组织超微结构的改变;并将三组剩余大鼠左眼眼球制备成5μm视网膜切片,常规HE染色后对视网膜神经节细胞进行计数。结果透射电镜观察模型组与实验组同空白组相比均存在线粒体水肿、胞质浓缩轴突肿胀。同模型组相比实验组胞质浓缩轴突肿胀轻,线粒体结构较完整。HE染色实验组和模型组的神经节细胞数都明显低于空白组(P<0.05),实验组神经节细胞从细胞形态上要好于模型组,且RGCs数量较模型组多。模型组和实验组神经节细胞计数较空白组分别下降73.3%、53.3%,两者差异有统计学意义(P<0.05)。结论视神经不全损伤可引起视神经超微结构的明显损害,PEDF可以减轻视神经超微结构的损害,并减少视网膜神经节细胞凋亡。

Objective To investigate the protective effect of pigment epithelium derived factor （PEDF） on mitochondria axon ultra structure of retinal ganglion cells （RGCs） in rats after acute optic nerve injury. Methods 60 SD rats were ran- domly divided into 3 groups： blank group, model group and experiment group, each group included 20 rats. The blank group was not given any disposal, rats in model group and experiment group were treated with forceps clamping left eye optic nerve to cause incomplete injury of optic nerve, the right eye was not given any disposal. The model group and experiment group, the left eyes models successfully made immediately, at 1 week and 2 weeks, the rats was injected balanced salt solution 5 p,L and PEDF 1 p,g into vitreous cavity respectively. Rats of three groups were harvested at the third week, 10 rats left eyeball were taken out to make specimens in each group, changes of retinal ultra structure was observed by the electron microscopy; the remaining rats were prepared to make 5 p,m retinal slices, the retinal ganglion cells were counted by routine HE staining. Results Mitochondria edema, cytoplasm condensed axon swelling existed in model group and experiment group, compared with the blank group by observing with the electron microscopy. Compared with model group, the degree of cytoplasm condensed axon swelling was lesser, and structure was more completely in the experiment group. HE staining showed ganglion cells in the experiment group and model group were less （P 〈 0.05）, cell morphology of ganglion cells were better and the number of RGCs were more in experiment group. The number of ganglion cell counts in model group and experiment group decreased by 73.3% and 53.3% respectively, the difference was statistically sig nificant （P 〈 0.05）. Conclusion Incomplete injury of optic nerve can cause obvious damage to the ultra structure of the optic nerve, and PEDF can relieve the damage of the ultra structure of the optic nerve., also can weaken the apoptosis of RGCs.