RCS大鼠视网膜色素变性过程中视网膜形态学研究

目的研究遗传性视网膜色素变性大鼠(Royal College of Surgeons rat,RCS rat)在视网膜变性发展过程中视网膜形态学变化.方法 RCS-p (视网膜含色素的变性大鼠)按出生后视网膜变性的发展状况分为变性早期(RCS15 d)、中期(RCS 30 d)、晚期(RCS90 d)3个时相点,分别采用相应时期的RCS-rdy p (视网膜含色素的正常大鼠)作为对照组(control groups,C 15 d,C 30 d,C 90 d),每组5眼,取各组大鼠眼球进行视网膜切片,行HE染色,采用MIAS-1000图像分析系统在400倍光镜下测视网膜外节(OS)、外核层(ONL)以及内核层(INL)厚度.结果①视网膜感光细胞随着病变的发展逐渐变性死亡,晚期视网膜色素上皮层和感光细胞层结构紊乱,但光镜下观察内核层、神经节细胞层仍保持较正常的形态.②与对照组比较,RCS大鼠视网膜色素变性过程中感光细胞外节膜盘堆积,外核层变薄,内核层在变性中期增厚,早期及晚期变薄.结论①RCS大鼠病变发展过程中视网膜各层神经元形态改变的不一致性.②变性中期视网膜内核层较对照组增厚,可能与该时期内核层神经元缺乏前级神经元的信号输入致细胞突起反应性增生,产生视网膜形态重构(remodeling)有关.

Morphological study of retina in RCS rats during retinal degeneration

Objective To investigate morphological changes of retina in the Royal College of Surgeons (RCS) rats with the onset and development of retinitis pigmentosa (RP). Methods The RCS rats with inherited retinal dystrophy were divided into 3 groups: an initial stage group (RCS 15 d), a mid-stage group (RCS 30 d) and an advanced stage group (RCS 90 d) according to the severity of degeneration (n=5 animals in each group). These were compared with RCS-rdy p rats without retinal degeneration (control groups, C 15 d, C 30 d, C 90 d). One retina of every animal was prepared for retinal slices and stained using hematoxylin-eosin (HE) method (The contralateral retina was prepared for other experiments). The thickness of outer segments (OS), outer nuclear layer (ONL) and inner nuclear layer (INL) was measured by MIAS-1000 image analysis system under light microscope. Results Photoreceptors of RCS rats were degenerated progressively. At late stage of retinal degeneration the structures of the retinal pigment epithelium (RPE) and photoreceptors layer were disorganized, but the morphology of inner nuclear layer and retinal ganglion cell (RGC) layer appeared normal. Compared with control groups, the breakdown of RPE caused a piling up of OS membranous disc photoreceptors of RCS rats with the onset and development of RP, and ONL thinning. However, INL was thickening in RCS 30 d, 15 d, and 90 d groups as compared with control groups. Conclusion The morphology of each layer neurons of retina in RCS rats remains change discordantly with the onset and development of RP. The thicker INL of retina in RCS rats in mid-stage group is possibly related with the reactive hyperplasia of cell processes and retinal morphology remodeling, which is resulted from lacking of signal input of fore-level neurons in retina INL.