Regulation of Egr-1, VIP, and Shh mRNA and Egr-1protein in the mouse retina by light and image quality

[摘要] Purpose: To analyze mRNA expression changes of Egr-1, VIP,and Shh under different light and treatment conditions in mice. ThemRNA expression levels of the three genes and additionally the Egr-1protein expression were compared in form deprived eyes and eyes withnormal vision. Moreover, the influence of dark to light and light todark transitions and of changes in retinal illumination on mRNA levelswas investigated.Methods: Form deprivation of mice was induced by fitting frosteddiffusers over one eye and an attentuation matched neutral density (ND)filter over the other eye. To measure the effects of retinalillumination changes on mRNA expression, animals were bilaterally fittedwith different ND filters. Semiquantitative real-time RT-PCR was used tomeasure the mRNA levels and immunohistochemistry was applied to localizeand detect Egr-1 protein.Results: The expression levels of both Egr-1 mRNA and proteinwere reduced in form deprived eyes compared to their fellow eyes after30 min and 1 h, respectively. Egr-1 mRNA was strikingly upregulatedboth after dark to light and light to dark transitions, whereas minorchanges in retinal illumination by covering the eyes with neutraldensity filters did not alter Egr-1 mRNA expression. In mice, themRNA levels of VIP and Shh were not affected by formdeprivation, but they were found to be regulated depending on the timeof day.Conclusions: Both Egr-1 mRNA and protein expression levels werestrongly regulated by light, especially by transitions between light anddarkness. Image contrast may exert an additional influence on mRNA andprotein expression of Egr-1, particularly in the cells in the ganglioncell layer and in bipolar cells.

[学科分类] 生物化学/生物物理