Colocalization of aldehyde dehydrogenases and Fe/NADPH-induced lipid peroxidation in tissue sections of rat retina

Epidemiological and experimental studies suggest the involvement of lipid p eroxidation (LPO) in retinal diseases. Clinicians usually prescribe antioxi dants to help in the treatment of proliferative diabetic vitreoretinopathy and age-related macular degeneration. In spite of this, these processes ine xorably induce visual impairment and may progress towards blindness. In add ition to other pathogenic mechanisms not fully understood, it may be that p eroxidic aldehydes from LPO occurring in the eyes, acting as cytotoxic chem icals, mediate in these chronic disorders. To test the mechanisms of removi ng peroxidic aldehydes from retinal cells and in an attempt to understand l ong-lasting changes induced by LPO, the distribution and activity of aldehy de dehydrogenases (ALDH) in the rat retina were studied and compared with t he LPO sites induced by iron/nicotine adenine dinucleotide phosphate, Histo chemical and immunocytochemical assays revealed the colocalization of LPO a nd ALDH, mainly in the photoreceptors and inner retinal layers. This sugges ts the involvement of ALDH in detoxifying peroxidic aldehydes from the reti na. Any change in ALDH retinal expression and distribution might be of cruc ial importance in assessing the paths of LPO-mediated vitreo retinopathies. Further research is needed to evaluate these findings and their applicatio n to new ophthalmic therapy. Copyright (C) 2000 S. Karger AG, Basel.