Imaging Hypoxia to Predict Primary Neuronal Cell Damage in Branch Retinal Artery Occlusion

ABSTRACT Purpose To develop a reliable method to generate a mouse model of branch retinal artery occlusion (BRAO) using laser‐induced thrombosis of a major artery in the mouse retina. Also, to develop a reliable method to detect retinal hypoxia as predictive biomarker for the risk of neuronal cell damage in BRAO. Methods A reliable and reproducible model of laser‐induced BRAO was developed in mouse retina using Rose Bengal. To characterize retinal hypoxia in BRAO, pimonidazole immunostaining and HYPOX‐4 molecular imaging methods were used. Terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) was used to characterize neuronal cell damage in the BRAO retina. Expression of mRNA in retinal tissues from BRAO and age‐matched control retinas were analyzed using qRT‐PCR. Results Occlusion of a branch retinal artery near the optic nerve head (ONH) caused a pattern of retinal tissue hypoxia covering about 12.5% of the entire retina. TUNEL‐positive cells were localized in all layers in BRAO retinal tissue cross sections. In addition, qRT‐PCR data analysis suggests that BRAO is associated with both inflammation and hypoxia. Conclusions This study provides a reliable method for BRAO in mouse retina and demonstrates the utility of molecular imaging method to detect retinal hypoxia as predictive biomarker for the risk of neuronal cell damage in BRAO. In addition, our data suggest that BRAO retinas are associated with inflammation and also associated with hypoxia‐related neuronal cell damage. Perspectives Imaging areas of retinal hypoxia may provide accurate diagnosis, evaluating retinal tissue injury from BRAO.