Protective limb remote ischemic post-conditioning against high-intraocular-pressure-induced retinal injury in mice

Abstract

AIM: To determine whether limb remote ischemic post-conditioning (LRIC) protects against high-intraocular-pressure (IOP)-induced retinal injury, and to identify underlying molecular mechanisms. METHODS: In mice, IOP was increased to 110 mm Hg for 50min and LRIC applied to the unilateral leg for three occlusion cycles (5min/release). Three animal groups (control, high IOP, and high IOP+LRIC) were arranged in this study. Plasma was collected from LRIC treated mice. Retinal histology, oxidative stress were determined by histological section staining and chemical kit. C/EBP homologous protein (CHOP), and Iba-1 parameters were evaluated by immunofluorescent staining and Western blot. RESULTS: The data showed that LRIC treatment alleviated the retinal histological disorganization and ganglion cell loss induced by high IOP. The CHOP, Iba-1 expression and oxidative stress marker also were inhibited by LRIC treatment. To further explore underlying mechanisms, plasma from LRIC treated animals was intravenously transfused into high-IOP animals. The results showed plasma injection decreased caspase 9 expression and DHE staining signals compared with that in high IOP retinas. CONCLUSION: These data suggest that LRIC treatments exert retinal protective effects against high-IOP injury. Endogenous humoral factors release into the circulation by LRIC may contribute to homeostatic protection by reducing monocyte infiltration and/or microglia activation.