c-Fos蛋白在远视离焦性近视幼恒河猴视皮质中的表达

c-Fos expression in visual cortex of infant rhesus monkeys with myopia induced by hyperopic defocus

目的观察c-Fos蛋白在远视离焦性近视幼恒河猴视皮质中的表达变化,探讨视皮质参与幼恒河猴近视发生的可能性。方法选取8只20~30日龄SPF级健康幼恒河猴,采用随机数字表法将实验动物随机分为远视离焦组和对照组。远视离焦组4只猴双眼均佩戴-3 D离焦镜片,形成双眼远视性离焦;对照组4只猴双眼均佩戴0 D镜片。分别于戴镜前和戴镜后2、4、6、8和12周进行扩瞳检影验光、电脑验光、角膜地形图检查、A型超声测量玻璃体腔长度。戴镜后12周取视皮质,分别采用免疫组织化学和Western blot法检测c-Fos蛋白的表达,进行半定量分析,分析并比较c-Fos蛋白在远视离焦组和对照组表达的差异。结果戴镜后12周,远视离焦组玻璃体腔长度的增加值明显大于对照组,差异有统计学意义[(0.93±0.24)mm与(0.72±0.09)mm;t=2.292,P=0.047];远视离焦组远视度数的减少值明显大于对照组,差异有统计学意义[(-3.23±1.36)D与(-1.55±0.52)D;t=-3.273,P=0.006],远视离焦组屈光度朝更为近视的方向进展。免疫组织化学染色结果显示,远视离焦组视皮质中c-Fos免疫阳性细胞数明显少于对照组,差异有统计学意义[(1 843±191)个/mm 2与(2 296±503)个/mm 2;t=2.381,P=0.041]。Western blot检测结果显示,远视离焦组视皮质中c-Fos蛋白的相对表达量少于对照组,差异有统计学意义(0.50±0.17与0.99±0.22;t=-4.982,P<0.01)。结论在幼恒河猴中,远视离焦这一异常视觉刺激导致近视发生,同时抑制视皮质中c-Fos蛋白的表达,提示视皮质可能参与远视离焦性近视的发生。

Objective To observe c-Fos expression in visual cortex of infant rhesus monkeys with myopia induced by hyperopic defocus and preliminarily investigate the possibility of visual cortex participating in myopia.Methods Eight SPF grade healthy infant rhesus monkeys aged 20 to 30 days were randomly divided into hyperopic defocused group and control group,4 monkeys for each group.The monkeys in hyperopic defocused group wore-3 D spectacle lenses.The monkeys in control group wore 0 D lenses.The monkeys'refractive error,corneal topography,vitreous chamber depth were measured at the start of lens wear and at 2,4,6,8,12 weeks post-treatment.At 12 weeks post-treatment,the visual cortex tissues were removed for c-Fos protein measurement by immunohistoc hemistry and Western blot assays.The results were analyzed semiquantitatively to compare the differences of c-Fos expression between hyperopic defocused group and control group.The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.This study protocol was approved by Ethic Committee of Zhongshan Ophthalmic Center(No.2013-014).Results After 12 weeks'lens wear,the vitreous chamber elongation amplitude of hyperopic defocused group monkeys was more obvious than that of the control group([0.93±0.24]mm vs.[0.72±0.09]mm;t=2.292,P=0.047).The decrease of hyperopic degrees of hyperopic defocused group monkeys was more obvious than that of the control group([-3.23±1.36]D vs.[-1.55±0.52]D;t=-3.273,P=0.006).The eyes of hyperopic defocused group monkeys appeared a remarkable myopic shift after treatment.The number of c-Fos immunoreactive neurons was less in the hyperopic defocused group than that in the control group,with a statistically significant difference between them([1 843±191]/mm 2 vs.[2 296±503]/mm 2;t=2.381,P=0.041).Western blot assay showed that the optical density of c-Fos protein in the hyperopic defocused group was significantly less than that in the control group(0.50±0.17 vs.0.99±0.22;t=-4.982,P<0.01).Conclusions Hyperopic defocus,as an abnormal visual stimulus,can induce the onset of myopia in infant rhesus monkeys and inhibit c-Fos expression in visual cortex.Visual cortex may participate in myopia induced by hyperopic defocus.