670 nm Red Light Preconditioning Supports Muller Cell Function: Evidence from the White Light-induced Damage Model in the Rat Retina

Glial cells play an important role in the maintenance of normal structure and function of the neural components of the central nervous system. The Muller cells are one of the macroglial elements in the retina and their wide-ranging roles are responsible for the protection and proper functioning of the photoreceptors. In the present study, we aimed to test the effects of pretreatment with 670 nm red light on Muller cells in the light-induced model of retinal degeneration. Adult Sprague-Dawley albino rats were treated with 670 nm red light, from an LED source prior to exposure to bright (1000 lux) continuous light for 24 h. Muller cell-specific markers were used to assess structural and functional changes in this cell type 1 week after contact with damaging light. Changes in gene (Edn2, LIF, TNF-a) and protein (S100 beta, Vimentin, LIF, iNOS, GS, Cyclin-D1) levels and localization were evaluated using RT-qPCR, and immunohistochemistry. Our results showed that 670 nm light pretreatment ameliorates the light-induced alterations in the expression of Muller-cell specific markers for structure, stress, metabolism and inflammation. This suggests that 670 nm light preconditioning may promote neuroprotective effects in the retina from light-induced damage, possibly through pathways regulating the roles of Muller cells in maintaining retinal homeostasis.