The role of clusterin in retinal development and free radical damage

Aim: To assess the role of clusterin in retinal vascular development and in free radical damage in vivo and in vitro. Methods: The expression of clusterin, von Willebrand factor (vWF), flk-1, heat shock protein 27 (Hsp27) and heat shock protein 70 (Hsp70) was examined in the retinas of developing mice and oxygen-induced retinopathy (OIR) mice by immunofluorescence staining and western blot analysis. Hydrogen peroxide (H₂O₂)-pretreated human retinal endothelial cells (HREC) and astrocytes were cultured in the presence or absence of exogenous clusterin, and then the cell viability was measured using the MTT assay and DAPI staining. Results: Clusterin was expressed mainly in the inner retina and co-localised with vWF, an endothelial cell marker. During the mouse developmental process, clusterin expression was decreased, which was similar to the expression of Rk-1, vWF and Hsp27. Furthermore, in the OIR model, clusterin expression changed in a similar way to both vWF and Hsp27. Under hypoxic conditions, clusterin expression increased in HREC and astrocytes. In H₂O₂-pretreated HREC and astrocytes, clusterin protected against apoptotic cell death. Conclusions: These results suggest that clusterin is associated with protection from apoptotic retinal cell death in retinal development and in free radical damage.