频闪光诱导光觉异常性豚鼠近视模型

Establishment of a guinea pig model of light perception myopia induced by flickering light

目的使用特制的频闪调光器进行持续频闪光刺激,建立一种光觉异常性豚鼠近视模型,观察豚鼠在频闪光刺激后眼球产生的异常改变。方法 24只2周龄普通级豚鼠随机分为3组(n=8),Ⅰ组予0.5 Hz频率等时交替频闪,频闪亮度0～600 lx;Ⅱ组为无频闪等亮度光照组;Ⅲ组为开放环境正常光照组。光照时间6∶00～18∶00。每2周记录屈光度、眼轴长度及曲率半径,12周时眼底拍照后取出眼球,光学显微镜及扫描电镜观察眼球后极部改变。结果光照前各组间生物学测量参数差异无显著性(P>0.05)。随时间延长,Ⅰ组与Ⅱ、Ⅲ组相比近视屈光度明显增加、眼轴延长,12周时3组间近视屈光度及眼轴差异有显著性(P<0.05),Ⅰ组与Ⅱ组相比眼球发生(-5.4±1.5)D的近视,眼轴增加(0.74±0.18)mm。Ⅰ组与Ⅲ组相比眼球发生(-6.6±1.5)D的近视,眼轴增加(0.86±0.24)mm。Ⅰ组眼底普遍出现豹纹状改变,视网膜感觉细胞层外段排列紊乱且有大量脱落节盘。结论通过改变正常光觉环境,频闪光能刺激豚鼠眼球产生过度发育并诱导轴性近视形成。这种光觉的异常最终影响了视网膜感光细胞的正常发育。

Objective To investigate the effectiveness and feasibility of a method to establish a guinea pig model of myopia induced by flickering light（FL） stimulation,and further observe the abnormal changes in this process.Methods Twenty-four 2-week-old guinea pigs were randomly assigned to FL group,non-flicker indoor light group,and daylight group（n=8 for each）.Animals in the FL group were raised under 600 lux illumination with a duty cycle of 50% at a flash rate of 0.5 Hz.Animals in the non-flicker light group and normal group were reared under 600 lux illumination and natural daylight,respectively.Refraction,axial length,and radius of curvature were measured before and after 2,4,6,8,10,12 weeks treatment.After the collection of fundus photographs,histopathological changes were examined by light and electron microscopy.Results The FL group developed rapidly towards myopia throughout experimental period.Significant difference was noted for refraction in all the 3 groups at 12th week,compared with the non-flicker light group.Eyes in the FL group were approximately-5.4±1.5 D more myopic with an increase in axial length by 0.74±0.18 mm.Compared with the daylight group,eyes in the FL group were approximately-6.6±1.5 D more myopic with an increase in axial length by 0.86±0.24 mm.As to the FL group,tessellated fundus appeared more prevalent,and the photoreceptor layer was more likely to develop a disordered outer segment,which contained much deciduous disc membranes.Conclusions Guinea pigs develop accelerated ocular growth and refractive myopic changes by flickering light.Such abnormal light perception ultimately influences the development of retinal photoreceptor cells.