Retinal ganglion cell loss in superoxide dismutase 1-deficiency

目的.目的探讨视网膜神经节细胞（RGCs）中主要抗氧化酶超氧化物歧化酶1（SOD 1）缺乏对RGCs的影响。方法.在SOD1总敲除（SOD1缺陷）小鼠中，使用二氢乙锭测量超氧阴离子的水平。逆行标记后，在视网膜切片和平托视网膜中计数RGC的数量。在切片中测量神经纤维层（NFL）的厚度，并通过免疫印迹分析测量神经丝蛋白的量。进行反映视网膜神经节细胞功能的图形视网膜电图、暗适应视网膜电图和视锥视网膜电图检查。用感应冲击式眼压计测量眼压。结果24周龄SOD 1缺陷小鼠RGC层中的超氧阴离子水平显着高于野生型小鼠。24周龄SOD1缺陷小鼠的RGC数量显著减少，但8周龄小鼠的RGC数量没有减少。NFL厚度和神经丝蛋白在24周龄SOD1缺陷小鼠中减少。在24周龄SOD1缺陷小鼠中，模式ERG的幅度显著降低，尽管暗适应和视锥ERG没有显示出损害。SOD1缺陷小鼠的IOP水平没有变化。

Purpose. To investigate the influence of deficiency in superoxide dismutase 1 (SOD1), a major antioxidative enzyme, on retinal ganglion cells (RGCs). Methods. In the SOD1 total knock-out (SOD1-deficient) mice, the level of superoxide anion was measured using dihydroethidium. The number of RGCs was counted both in the retinal sections and the flat-mount retinas after retrograde labeling. Thickness of nerve fiber layer (NFL) was measured in the sections and the amount of neurofilament protein was measured by immunoblot analysis. Pattern electroretinogram (ERG) which reflects the function of retinal ganglion cells, dark-adapted ERG, and cone ERG were performed. The intraocular pressure (IOP) was measured with an induction-impact tonometer. Results. The level of superoxide anion in the RGC layer was significantly higher in 24-week-old SOD1-deficient mice than in wild-type mice. The RGC number was significantly reduced in 24-week-old SOD1-deficient mice, although they were not in 8-week-old mice. The NFL thickness and neurofilament protein were reduced in 24-week-old SOD1-deficient mice. The amplitude of pattern ERG was significantly reduced, although dark-adapted and cone ERGs showed no impairment, in 24-week-old SOD1-deficient mice. The IOP level was not changed in the SOD1-deficient mice.