RCS大鼠视网膜内核层变性的超微结构研究

Neuronal degeneration in the inner nuclear layer of RCS rat

目的 证实RCS大鼠视网膜内核层存在神经原变性。方法 利用光学显微镜和透射电子显微镜观察出生后第 18、2 0、2 8、3 5、42、45、5 6、60、70和 10 0d的RCS大鼠视网膜和正常SD大鼠视网膜组织结构的变化。并用TUNEL方法证实视网膜神经细胞存在凋亡。结果 和正常SD大鼠视网膜比较 ,RCS大鼠 18～ 2 0d开始视网膜变性 ,光感受器细胞死亡 ,内核层细胞也有不同程度的变性。RCS大鼠在出生后 2 5d ,视网膜外核层细胞核TUNEL呈阳性 ,出生后 3 5～ 45d呈强阳性 ,视网膜内核层细胞核TUNEL标记呈阳性。结论 RCS大鼠视网膜内核层细胞存在神经原变性 ,视网膜内核层细胞死亡存在凋亡这一方式。跨神经原变性很可能是这些细胞变性的机制。RCS大鼠视网膜外核层细胞存在神经原变性 。

Objective To determine the neuronal degeneration in the inner nuclear layer of retina in RCS rat. Methods Retinal tissue was collected from the RCS rats aged 18,20,28,35,42,45,56,60,70 and 100 days.The retinas of normal age-matched SD rats served as control.Horizontal cell,rod bipolar cells and amacrine cells were observed by light micropscopy and electron microscopy,and apoptosis of neuronal cells in retinas were assessed by TUNEL. Results Compared with normal SD rat retinas,retinal degeneration,including outer and inner nuclear layers,was observed in RCS rat retina in post-natal 1820 days.Morphometric study at varying periods showed degeneration of horizontal cells,rod bipolar cells and amacrine cells in the inner nuclear layer of RCS rats.TUNEL positive nuclei were seen in the outer nuclear layer(ONL) in 15-to 55-day rats with maximal activities at the age of 35 to 45 days.Positive TUNEL were seen in the inner nuclear layer(INL) at the age of 35 to 45 days also. Conclusion Evidence for the existence of neuronal degeneration and apoptosis cells in the outer nuclear layer and the inner nuclear layer of RCS rats is presented,and its probable mechanism could be transneuronal degeneration.