RCS大鼠视网膜变性过程中α亚型神经节细胞树突形态学变化

Dendrite morphological characteristics during degenerative process of retinal ganglion cells in royal college surgeons rats

目的研究皇家外科学院大鼠(royal college of surgeon rat,RCS)视网膜变性过程中α亚型视网膜神经节细胞(retinal ganglion cells,RGCs)树突形态学变化规律。方法按照视网膜色素变性发展的不同阶段,选取出生后21、30、60、90d的RCS-P+大鼠(RCS组)与RCS-rdy+大鼠(对照组)各3只,采用DiI示踪标记方法观察RCS组α亚型视网膜神经节细胞的树突在视网膜变性过程中形态学变化的规律。结果RCS组各天龄间、对照组大鼠发育过程中各天龄间、RCS组与对照组相对应天龄段间一、二级分支数目之间比较无显著差异(P>0.05)。RCS组大鼠视网膜变性过程中,α亚型RGCs树突一级分支直径60d组较21d组变细[(2.02±0.17)μmvs(2.66±0.11)μm,P<0.01],RCS组与对照组大鼠α亚型RGCs树突一级分支直径比较,21d增粗[(2.66±0.11)μmvs(2.23±0.10)μm,P<0.01]。RCS组90d(15.44±1.50)较21d(26.91±3.01)、30d(27.20±1.99)α亚型RGCs细胞树突分支频率显著减少(P<0.01,P<0.05)。对照组大鼠发育过程中α亚型RGCs树突分支频率比较,60d(28.67±2.78)较21d(16.09±1.71)、30d(17.75±1.79),90d(26.18±2.48)较21d组有显著增加(P<0.01,P<0.05),其余各组间没有明显差异(P>0.05)。RCS组与对照组大鼠α亚型RGCs树突分支频率相对应21、30、60、90d组间比较均有显著差异(P<0.05)。结论RCS大鼠视网膜色素变性过程中,视网膜α亚型RGCs树突分支频率在早期增多,但随着病变的发展到中、晚期树突终末分支显著减少,提示在视网膜变性过程中α亚型RGCs树突的信息传递功能可能发生了变化。

Objective To study the morphological diversity of retinal ganglion cells （RGCs） in the pathological development of retinitis pigmentosa in royal college of surgeon （RCS） rats.Methods The retinal whole mount preparations of RCS-P＋and RCS-rdy＋ rats in 21,30,60 and 90 d were stained by DiI to study the morphological diversity of retinal ganglion cells.Results In the pathological development of the retina of the RCS rats,the amount of first and second level of dendrite branching,the diameter of first level of dendrite branching,and the frequency of dendrite branching of α subgroup of retinal ganglion cells had no significant difference with each other （P〈0.05）.The diameter of dendrite branching at the first level of α subtype of RGCs was markedly increased by 0.44 μm on the 60th day compared with on the 21st day during the degenerative process of RCS-P＋ rats（2.02±0.17 vs 2.66±0.11 μm,P〈0.01）.Moreover,the diameter of of those dendrite branching at the first level was markedly increased by 0.43 μm compared with RCS-rdy＋ rats on the 21st day（2.66±0.11 vs 2.23±0.10 μm,P〈0.01）.The frequency of dendrite branching of α subtype of RGCs was significantly decreased on the 90th day （15.44±1.50） compared with that at the 21st （26.91±3.01,P〈0.01）and 30th days （27.20±1.99,P〈0.05） respectively during the degenerative process of RCS-P＋ rats.In contrast,the frequency of dendrite branching of α subtype of RGCs was increased significantly in the 60th day （28.67±2.78） than in the 21st （16.09±1.71） and 30th days（17.75±1.79） （P〈0.01）,and in the 90th （26.18±2.48） day than in the 21st day （P〈0.05） during the development of RCS-P＋ rats.In addition,there were also differences in frequency of dendrite branching of α subtype of RGCs between RCS-P＋ and RCS-rdy＋ rats on the 21st,30th,60th,and 90th days respectively.Conclusion In the pathological development of retinitis pigmentosa,frequency of dendrite branching of α subgroup of RGCs is increased significantly in the early stage,while the frequency of dendrite branching is decreased during middle and late stage.Our research suggests that the process of α subgroup of retinal ganglion cells may have changed in the retinal degeneration of dendrites of the information transmission function.