Figure 4. Effects of hyperoxia in rabbit lenses after 7 d incubation compared with controls and the NAC treatment. A: The water-soluble protein in rabbit lenses (mean±SD). Lenses exposed to hyperoxia (group B) had a significant reduction in the water-soluble protein (*p<0.05). Compared with the hyperoxia-exposed group (group B), the level of water-soluble protein was increased dramatically in the 20 mM and 40 mM NAC-treated groups (*p<0.05). No significant differences were observed between any other two groups. B: The effect of NAC on GSH content of rabbit lenses (mean±SD). Lenses exposed to hyperoxia (group B) had a significant reduction of GSH (*p<0.05). A statistically significant difference was observed between the hyperoxia group (group B) and the 20 mM NAC-treated group (group E; *p<0.05). No significant differences were observed between any other two groups. C: The effect of NAC on the activity of Na, K-ATPase in rabbit lenses (mean±SD). Lenses exposed to hyperoxia (group B) had a significant reduction of Na, K-ATPase activity (*p<0.05). Compared with the hyperoxia-exposed group (group B), the activity of Na, K-ATPase was increased dramatically in the 20 mM and 40 mM NAC-treated groups (*p<0.05), but did not fully restore it to the normal level. No significant differences were observed between any other two groups. D: The effect of NAC on the activity of CAT in rabbit lenses (mean±SD). Lenses exposed to hyperoxia (group B) had a significant reduction of CAT activity (*p<0.05); Compared with the hyperoxia-exposed group (group B), the activity of CAT was increased dramatically in the 20 mM and 40 mM NAC-treated groups (*p<0.05). No significant differences were observed between any other two groups. E: The effect of NAC on the activity of GR in rabbit lenses (mean±SD). No significant difference was noted between groups. Group A was the control group, group B was the hyperoxia-exposed rabbit lenses group, group C-F were 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).