视网膜内源性NO在形觉剥夺性近视眼中的作用

目的 :建立鸡形觉剥夺性近视 (form deprivationmyopia ,FDM)模型 ,探讨视网膜内源性NO在FDM发展中的变化及作用。方法 :取出生当日的来亨鸡 6 0只 ,分为A ,B两组 ,A组持续遮盖 3周 ,B组遮盖 2周后去遮盖 1周。随机遮盖一眼 ,另眼作对照。于实验前、1,2 ,3周 ,行视网膜检影和A超检查。NO酶法试剂盒测定视网膜和脉络膜组织的NO含量。RT PCR检测iNOSmRNA的表达 ,免疫组织化学分析iNOS的活性。结果 :形觉剥夺使遮盖眼轴长增加 ,近视屈光度增加 ,去遮盖后双眼轴长差异减小 ,近视度下降。形觉剥夺降低视网膜和脉络膜组织NO含量、iNOS的免疫反应和iNOSmRNA的表达 ,去遮盖后逐渐恢复 ,去遮盖后 1周 ,iNOSmRNA的表达高于对照组水平。结论 :形觉剥夺可以建立近视眼动物模型 ,NO可能参与FDM的形成 ,未成熟动物的FDM是可逆的。

Effects of nitric oxide on form-deprivation myopia in chicks

Objective To construct a chick model of form-deprivation myopia (FDM) to investigate the effect of nitric oxide(NO) on FDM. Methods FDM was induced in 60 one-day white leghorn chicks. They were divided into group A and B. One eye was covered randomly, and the other served as control. In each week of the experimental period, the retinoscopic refraction was performed, and the axial length was measured with A-mode ultrasound. The NO concentration of retina and choroid from the control and the experimental eyes was measured using NO detection kit. Change in the expression of iNOS mRNA was measured by RT-PCR. The activity of iNOS was analyzed with immunohistochemistry.Results Form-deprivation eyes were significantly more myopic than the controls, and the axial length of occluded eyes was significantly longer than that of the controls.Unocclusion attenuated the development of myopia and inhibited the axial elongation.Form-deprivation reduced the NO concentration,the immunoreactivity of iNOS, and the expression of iNOS mRNA.The gradual restoration of normal vision was found after uncovering the eyes.But the expression of iNOS mRNA was significantly higher than that of the controls at the first week after the unocclusion.Conclusion Form-deprivation can construct an animal model of myopia. FDM is reversible before the chicks were mature. NO may be involved in the form of FDM.