Macrogilal Retinal Cells Show A Bilateral Early Activation In A Mouse Model Of Unilateral Laser-Induced Experimental Glaucoma

Purpose To describe macroglial morphological features of activation after 24 h of unilateral laser-induced ocular hypertension (OHT) in OHT-eyes and their contralateral eyes. Methods Albino Swiss mice were divided into two groups, naïve (n = 6) and lasered (n = 6). Retinal whole-mounts were immunolabeled with antibodies against GFAP and MHC-II. Results With respect to naïve, OHT eyes and contralateral eyes showed different features of macroglial activation in some retinal areas: i) Müller cells were reactive and expressed GFAP; ii) astrocytes were more robust and had more primary and secondary processes; and iii) MHCII was up-regulated in astrocytes and in some Müller cells. In contralateral eyes, these signs were observed mainly in the periphery. In addition, in the OHT eyes: i) in some retinal vessels near the optic disc, the astroglial reactivity was so intense that the entire vascular walls were sheathed by astroglial cells; ii) in some areas of the retina, astrocytes and Müller cells formed glial scars. iii) MHC-II immunoreaction in astrocytes varied depending on the retinal area; in those in which MHC-II immunostaining was less intense, only astrocyte primary processes could be recognized; Conclusions At 24 h after unilateral OHT, macroglia showed features of activation not only in OHT eyes, but also in untreated contralateral eyes. Early up-regulation of MHC-II in macroglial cells in both OHT retinas and contralateral retinas, suggest an immune system-related inflammation early after the induction of ocular hypertension.