Hyperoxia-induced lens damage in rabbit: protective effects of N-acetylcysteine

PURPOSE To investigate the efficacies of different concentrations of N-acetylcysteine (NAC) in preventing hyperoxia-induced lens opacification and changes to biochemical parameters in organ-cultured rabbit lenses. METHODS Thirty-six lenses from adult rabbits were divided into the control group (group A), the hyperoxia-exposed group (group B), and the hyperoxia-exposed, NAC-treated groups: 5 mM NAC (group C), 10 mM NAC (group D), 20 mM NAC (group E), and 40 mM NAC (group F). Groups B-F were incubated with hyperoxia (pO(2)>80%) for 4 h per day for 7 d. Lens transparency, histology, and enzymatic activities were measured after incubation. RESULTS Gross examination of these lenses revealed some severe cortical opacification in group B, and moderate cortical opacification in the lenses of groups C and D. There was minimal cortical opacification in groups A, E, and F. The activities of Na, K-ATPase, and catalase were significantly (p<0.05) lower in group B (38.2%) than in group A (39.9%). It was also lower in group E and F lenses (p<0.05), which had higher levels of NAC-protected enzymes. The glutathione and water-soluble protein content were significantly lower in group B lenses than in group A, E, or F lenses (p<0.05). However, there was no difference between group E and F lenses (p>0.05). CONCLUSIONS The present data suggests that NAC (20 mM-40 mM) significantly prevented experimental lenses' hyperoxia-induced cortical opacification, indicating NAC's potential role in protecting lenses against cataracts induced by high oxygen levels.