The Neuroprotective Potential of Rho-Kinase Inhibition in Promoting Cell Survival and Reducing Reactive Gliosis in Response to Hypoxia in Isolated Bovine Retina

Abstract

Aims: To investigate the outcomes of Rho-kinase inhibition in the electrophysiological ex vivo model of the isolated perfused vertebrate retina under hypoxia. Methods: Bovine retinas were perfused with an oxygen saturated nutrient solution with or without the Rho-kinase inhibitor H-1152P. The retinas were stimulated repeatedly until stable amplitudes were reached and the electroretinogram was recorded at five minute intervals. Hypoxia was induced for 15, 30, and 45 minutes, after which the oxygen saturation was restored. The extent of the cell damage and glial reactivity was determined by Ethidium homodimer-1 staining, immunohistochemistry, and Western blot. Results: Hypoxia caused a time-dependent reduction of the b-wave amplitudes, which could not be prevented by the H-1152P. Although the Rho-kinase inhibitor maintained higher b-wave amplitudes, these effects did not reach statistical significance. Hypoxia also resulted in an increase in cell damage and the activation of the glial cells in the untreated retinas whereas the administration of H-1152P significantly reduced the extent of these events. Conclusion: H-1152P exerted a neuroprotective effect against necrosis on the isolated bovine retina under hypoxia together with a reduction in glial cell reactivity. However, the inhibitor could not prevent the hypoxia induced retinal dysfunction possibly due to the interference with synaptic modulation.