Reactive oxygen species upregulate the production of VEGF and MMPs in retinal glial cells

Abstract

Abstract: : Purpose: We have recently shown that retinal glial cells play important roles in both angiogenic (Ishida S et al, IOVS, 2000) and proteolytic (Noda K et al, IOVS, 2003) activities for diabetic fibrovascular proliferation. The aim of the present study is to investigate whether reactive oxygen species (ROS), which are known to be accumulated in the diabetic retina, induce the expression of vascular endothelial growth factor (VEGF) and matrix metalloproteinases (MMPs) in retinal glial cells in vitro. Methods: Müller glial cells are harvested from the nonvascular region of rabbit retinas, and cultured for this study. Immunohistochemistry was performed to see whether the isolated cells are positive for glial fibrillary acidic protein (GFAP). For the stimulation with ROS, hydrogen peroxide (HP) or phenazine methosulfate (PMS) was added to the cultured medium. Expression levels of VEGF, membrane type (MT) 1–MMP, MMP–2 and MMP–9 were examined by semi–quantitative and real–time reverse transcription–polymerase chain reaction (RT–PCR). Results: Immunohistochemistry for GFAP confirmed the origin of isolated cells to be glial cells. RT–PCR analyses demonstrated the dose– and time–dependent induction of VEGF, MT1–MMP, MMP–2 and MMP–9 by the treatment of HP or PMS. Conclusions: These findings suggest that ROS contribute to fibrovascular proliferation in diabetic retinopathy through upregulation of VEGF and MMPs in glial cells.

Keywords: retinal culture • oxidation/oxidative or free radical damage