Objective To investigate the triggering mechanisms of retinal ganglion cells (RGCs) alterations in retinally degenerative rats. Methods Retinal dystrophic Royal College of Surgeons (RCS-p+) and control RCS rats (RCS-rdy+-p+) were divided into three groups according to postnatal days, including postnatal 21 days (P21d), P60d and P90d, with six rats in each group. Fluorogold was injected into superior colliculus and lateral geniculate body for retrograde labeling RGCs. Then retinal flat mounts were observed under fluorescence microscope to investigate the morphological and RGC changes in density during retinal degeneration. Living retinal mounts or sections were prepared to investigate the calcium concentration of RGCs using a laser confocal microscope. Results At P90d RGCs of control rats were distributed throughout entire retina and appeared uniform. The soma and processes were apparent and clear. But at P90d RGCs of RCS-p+ rats were distributed sparsely in retina. The soma seemed messy and the number and dendritic fields decreased greatly, and some baculiform or broken cells appeared. RGC density was 5 421.0 plusmn;72.1/mm2 at P21d, 4 195.0 plusmn;136.4/mm2 at P60d and 2 906.0 plusmn;133.2/mm2 at P90d. At P21d there were no obvious differences in RGCs density between RCS-p+ and control rats (t=-1.301, P＞0.05). At P60d and P90d there were significant differences in RGC density (t=16.172, 30.131; P＜0.01). At P21d there was no significant differences in RGC intracellular calcium fluorescence intensity between RCSp+ and control rats (t=-1.545, P＞0.05). At P60d and P90d the intracellular calcium fluorescence intensity decreased obviously and the differences were significant (t=-18.058,-15.015; P＜0.01). Conclusions RGCs were secondarily impaired following the loss of photoreceptors at late stages of retinal degeneration, and the morphological and cell density of RGCs were affected. The overloading of intracellular calcium concentration may be the triggering factor of degeneration and death of RGCs in retinally dystrophic rats.
Citation： 闫明,宋艳萍,李付亮,陈中山. Triggering mechanisms of retinal ganglion cell alterations in retinally degenerative rats. Chinese Journal of Ocular Fundus Diseases, 2012, 28(3): 272-275. doi: Copy