| Sumario: | Objective: To investigate the biochemical effects of leptin and leptin plus L-NAME on retinal nitrotyrosine, malondialdehyde, and superoxide dismutase levels in a model of hypercarbic oxygen induced retinopathy in rats. Material and Methods: Forty newborn rat pups were divided into four groups consisting of leptin, leptin plus L-NAME, hyperoxia and sham groups. All groups, except the sham group, were exposed to ten minutes of hypercarbia followed by ten minutes of hyperoxia twice a day with an interval of 30 minutes. This protocol was performed for three days and then pups were sacrificed. The retinas were dissected and retinal nitrotyrosine, superoxide dismutase and malondialdehyde levels were measured. Results: The highest retinal nitrotyrosine levels were measured in the leptin group followed by the hyperoxia group (p< 0.05). Leptin plus L-NAME and the sham group showed similar results, indicating an antioxidative role for L-NAME (p< 0.05). Superoxide dismutase levels were also lower in the Leptin plus L-NAME group when compared to the hyperoxia group (p< 0.05). Conclusion: This study showed that leptin-induced retinal oxidation may be prevented by nitric oxide synthase inhibitors. We showed the protective role of L-NAME against nitric oxide mediated peroxynitrite toxicity. Further research should be carried out to investigate the role of nitrotyrosine on oxygen induced retinopathy.
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