昼夜节律的改变对视网膜感光视蛋白melanopsin表达的影响

Effects of circadian rhythm changes on expression of opsin photopigment melanopsin in mouse retina

目的研究昼夜节律的改变对视网膜感光视蛋白melanopsin表达的影响。方法出生14 d(P14)C57BL/6J小鼠随机分为实验组和正常对照组,实验组每天给予24 h持续光照,对照组模拟正常昼夜节律每天给予12 h光照、12 h黑暗环境,运用免疫荧光染色结合RT-PCR技术,分别检测实验组和对照组小鼠在光照1周后和8周后视网膜感光视蛋白melanopsin的表达情况。结果免疫荧光染色结果显示感光视蛋白melanopsin主要位于视网膜神经节细胞层,少部分位于内核层。小鼠光照1周后melanopsin阳性细胞的表达数目实验组少于对照组;RT-PCR结果示小鼠光照1周和8周时melanopsin的mRNA含量实验组均少于各自的对照组,两者具有统计学意义(P<0.01)。结论持续光照可以减少视网膜感光视蛋白melanopsin的表达,提示melanopsin阳性神经节细胞为光敏感性细胞,其表达可能对维持正常的昼夜节律有重要作用。

Objective To investigate the effects of circadian rhythm changes on the expression of opsin photopigment melanopsin in the retinsa.Methods 14-day old C57BL/6J mice were randomly divided into experimental group and control group.The experimental group was maintained in continuous light.The control group was maintained in a 12：12 h light：dark cycle.Fluorescence immunocytochemistry and RT-PCR assays were used to detect the expressions of melanopsin at 1 week and 8 weeks after the light exposure.Results The results of fluorescence immunocytochemistry showed that opsin melanopsin mainly expressed in the retinal ganglion cell layer and little in the inner nuclear layer.The total amount of melanopsin cells in the experimental group were less than that in the control group 1 week later.RT-PCR indicated that the total amount of melanopsin mRNA in the experimental group was less than that in the control group（P0.01）.Conclusions Constant lighting down-regulates the expression of melanopsin.Melanopsin-expression ganglion cells are photosensitive and may play an important role in the maintenance of normal circadian rhythm.