An in vitro model of ischemic-like stress in retinal pigmented epithelium cells: protective effects of antioxidants.

We have developed a model of in vitro cell oxidative stress in bovine retinal pigment epithelium cells exposed to a ischemia-like condition obtained by interference with glucose utilization through both oxidative phosphorylation and glycolysis. This resulted in a statistically significant decrease of the intracellular ATP levels, which reflects a bioenergetic decline similar to that associated with mitochondrial damage or loss in normal post-mitotic cells aging in vivo. This new model of cellular oxygen stress seems adequate for investigation of the protective action of antioxidants, in agreement with our finding of a statistically significant increase in the ATP levels over the values of the non-treated samples in retinal pigment epithelium cells exposed to the above oxygen stress in medium supplemented with 300 microM vitamin C or 10 mM N-acetylcysteine.

Antioxidant therapy in the treatment of experimental acute corneal inflammation.

To ascertain the effectiveness of topical antioxidant therapy on acute corneal inflammation, we have studied the effectiveness of topical treatment with a saline solution and with antioxidants such as 0.2% superoxide dismutase and 0.5% dimethylthiourea (DMTU) in a controlled experimental study. The evolution of the inflammatory process was evaluated by a multimodel approach, including computer-assisted planimetry of the corneal ulcer and infiltrate, ultrasonic pachymetry, luminol-amplified chemiluminescence and the study of corneal transparency by direct spectral spectrophotometry transmittance. The experimental model was a corneal ulcer created by a 60-second application of 1 N sodium hydroxide. Topical treatment with DMTU was shown to significantly improve all parameters tested, while superoxide dismutase reduced only the corneal ulcers. Antioxidant topical therapy with DMTU was shown to be efficient in reducing the inflammatory reaction that occurs during acute corneal inflammation. This suggests that antioxidant therapy could be considered as a complementary treatment in the pharmacological modulation of acute corneal inflammation.