树鼩形觉剥夺性弱视模型的视网膜形态变化

Retinal morphological changes in tree shrew model with form deprivation amblyopia

目的 建立形觉剥夺性树鼩弱视模型,从形态学方面观察弱视形成及恢复过程中视网膜的变化,为进一步探究弱视形成及恢复机制提供理论依据。方法 30只出生18 d的树鼩幼崽随机被分为6组(每组5只):弱视模型N1组(左眼缝合2个月);弱视模型N2组(左眼缝合1个月);弱视恢复模型N3组(左眼缝合1个月后打开1个月);弱视恢复模型N4组(左眼缝合1个月后打开换缝合右眼1个月);C1对照组(双眼正常视物2个月);C2对照组(双眼正常视物1个月)。模型建立成功后取视网膜行HE染色和透射电镜检查,观察在不同干预条件下树鼩视网膜各层组织学和超微结构变化。结果 HE染色结果显示,与C2对照组相比,弱视模型N2组树鼩视网膜神经节细胞、双极细胞、视锥视杆细胞数量均明显减少(均为P<0.05),神经纤维层及各层细胞形态均有不同程度损伤。透射电镜结果显示,弱视模型N2组树鼩视网膜各细胞出现细胞核体积缩小、核不规则、异染色质增多、线粒体肿胀、嵴溶解消失、内质网池形成等现象。在形觉剥夺时间更长的弱视模型N1组树鼩中,视网膜细胞数量较弱视模型N2组明显下降(P<0.05),形态损伤更加严重。去除剥夺后,弱视恢复模型N3组树鼩视网膜各层细胞数量均明显增多(均为P<0.05),细胞形态与超微结构出现一定程度的恢复,但与C1、C2对照组相比仍有差距。结论 形觉剥夺性弱视可引起弱视眼视网膜细胞出现病理性变化。形觉剥夺性弱视所引起的视网膜损伤具有可塑性。

Objective To investigate the retinal changes during the formation and recovery of amblyopia from the morphological aspect by establishing a form deprivation myopia(FDM)model in tree shrew,so as to provide a theoretical basis for further study of the mechanism of amblyopia formation and recovery.Methods Thirty 18-day-old tree shrews were randomly divided into 6 groups,with 5 tree shrews in each group:amblyopia model N1 group(left eye sutured for 2 months),amblyopia model N2 group(left eye sutured for 1 month),amblyopia recovery model N3 group(left eye sutured for 1 month and opened for 1 month),amblyopia recovery model N4 group(left eye sutured for 1 month and opened with right eye sutured for 1 month),C1 control group(normal vision in both eyes for 2 months),and C2 control group(normal vision in both eyes for 1 month).After the modeling,retinas were extracted for hematoxylin-eosin(HE)staining and transmission electron microscopy to survey the histology and ultrastructure changes of the cells in each layer of the retinas under different interventions.Results The HE staining showed that the number of retinal ganglion cells,bipolar cells,rod and cone cells in the retinas of tree shrews in the amblyopia model N2 group significantly reduced compared with those in the C2 control group(all P<0.05)and the cell morphology of nerve fiber layer and other layers were damaged to different degrees.Transmission electron microscopy results showed that the retinal cells of the amblyopic model N2 group showed nuclear volume reduction,irregularity,heterochromatin increase,mitochondrial swelling,disappearance of cristae dissolution,and formation of endoplasmic reticulum pools.In the amblyopia model N1 group with more prolonged form deprivation,the number of retinal cells significantly decreased compared with that in the amblyopia model N2 group(P<0.05),and the morphological damage is more serious.After removal of deprivation,the number of retinal cells in all layers in the amblyopia recovery model N3 group increased significantly(all P<0.05);the cell morphology and ultrastructure recovered to a certain degree,but there was still a gap compared to C1 control group and C2 control group.Conclusion FDM may cause pathological changes in the retinal cells of amblyopic eyes.Retinal damage caused by FDM is plastic.