视黄酸对视网膜感光细胞增生作用的实验研究

Experimental studies of effects of retinoic acid on the proliferation of retinal cells

目的 探讨外源性视黄酸是否能诱导成年大鼠视网膜感光细胞增生。方法 将 32只成年健康Sprague Dawley(SD)大鼠 ,每只体重约 2 0 0～ 2 5 0g ,随机平均分成 4组。第 1、2组 :视网膜下腔注射视黄酸 (retinoicacid ,RA) 5 μl(0 0 0 1mol/L) ,第 3、4组玻璃体腔注射RA 10 μl(0 0 0 1mol/L)。其中第 1、3组在注射RA前 ,通过结扎眼动脉 ,造成眼部缺血再灌注损伤的实验模型。对照组为 5只健康SD大鼠 ,在不注射RA的条件下 ,制做短暂缺血再灌注损伤模型。实验眼于注射RA后 2～ 4周取出眼球 ,进行HE和免疫组化染色 ,于光镜下检测分析。结果 第 1组 ,于注射RA后第 16天 ,视网膜下腔表达视杆细胞特异性标记抗体的视网膜感光细胞数量增多及内核层增厚 ;而第 2组未发现任何细胞增生 ;第 3、4组 ,玻璃体腔内注射RA后 ,无论在有无缺血再灌注损伤的条件下 ,均未见视网膜神经细胞数量增多。对照组在未注射RA的条件下 ,将组织学切片置光镜下观察 ,未见视网膜神经上皮层的形态学改变 ,也无感光细胞增生。结论 在缺血再灌注损伤的条件下 ,成年大鼠视网膜下腔注射外源性RA能够诱导视网膜感光细胞增生 。

Objective To determine whether the application of exogenous retinoic acid (RA) may induce the proliferation of retinal cells in adult rat. Methods Thirty two healthy adult Sprague Dawley (SD) rats were randomly divided into 4 groups. In Group 1 and Group 2, all trans RA (5 μl, 0 001 mol/L) was injected into the subretinal space. In Group 3 and Group 4, all trans RA (10 μl, 0 001 mol/L) was injected into epiretinal vitreous space. In the Group 1 and Group 3, transient ischemic reperfusion injuries of the experimental eyes were induced by ligating ophthalmic artery prior to RA treatment. In the control group, 5 SD rats were treated by ischemia reperfusion injuries but no exogenous RA application. The treated eyes were enucleated for light microscopic analysis and immunohistochemical assays after 2 4 weeks of RA application. Results In group 1, the number of the retinal cells expressing rod specific opsin marker in the subretinal space was significantly increased and the thickness of inner nuclear layer was also increased after the RA treatment for 16 days. However, no cell proliferation was detected in group 2. There were also no changes within population of retinal cells in Group 3 and Group 4 in which RA was injected into epiretinal vitreous space no matter under the ischemia reperfusion or non ischemia reperfusion. In the control group, there were no significant morphological changes within the neural retinal layers as well as photoreceptor proliferation. Conclusions The application of RA in the subretinal space can induce photoreceptor proliferation in adult rat under an ischemic reperfusion injury condition. It will provide a new idea for the regeneration of neural retinal cells.