目的 观察抗氧化剂N-乙酰-L-半胱氨酸（N-acetyl-L-cysteine，NAC）和过氧化氢酶（catalase，CAT）对晶状体上皮细胞凋亡的抑制作用及对凋亡关键蛋白酶caspase-3活性的影响。方法 离体大鼠晶状体于MEM培养液中培养，过氧化氢（H2O2）组加入H2O2使其最后浓度为2mM，对照组不加H2O2，两个抗氧化剂组除加入2mM H2O2外再分别加入100μM NAC和900U/mlCAT。培养24h后观察晶状体透明度改变，透射电镜下观察细胞超微结构改变，流式细胞AnnexinV-PI双染色法检测细胞凋亡率，并用Western blot法分析caspase-3 20kDa活性亚单位的表达。 结果 2mM H2O2作用24h 后可引起晶状体明显混浊，透射电镜下晶状体上皮细胞出现典型的凋亡形态学改变，细胞凋亡率上升到（31.20±3.31）%，并伴随caspase-3酶活性增高；分别加入抗氧化剂 NAC和CAT后，晶状体混浊度明显减轻，细胞凋亡率下降到（20.90±3.16）%和（15.02±2.41）%（P<0.01），同时二者均使caspase-3酶活性降低。结论 NAC和CAT可有效抑制氧化损伤引起的晶状体混浊及上皮细胞凋亡，其抑制作用可能与降低caspase-3酶活性有关。
[Abstract] Objective To investigate the effect of antioxidants N-acetyl-L-cysteine and catalase on H2O2-induced apoptosis of lens epithelial cells and the activity of caspase-3. Methods Vitro rat lenses were incubated in MEM involving 2mM H2O2 (H2O2 groups) and exclusive of H2O2 (control groups), antioxidants 100μM N-acetyl-L-cysteine and 900U/ml catalase were used to block the oxidative injury of lens epithelial cells respectively. Lens opacification and apoptosis of lens epithelial cells were detected using transmission electron microscope and AnnexinV-PI methods after incubating 24 hours. The activity of caspase-3 was analyzed by Western blot method at the same time. Results The observations revealed that 2mM H2O2 could apparently induce lens opacification and lens epithelial cell apoptosis in vitro, the apoptosis rate increased to （31.20±3.31）% after 24 hours incubation, which is also the time when caspase-3 was activised. Treatment with N-acetyl-L-cysteine and catalase could inhibit lens opacification , apoptosis and caspase-3 activation induced by H2O2. The apoptosis rate decreased to （20.90±3.16）% and （15.02±2.41）% respectively(P<0.01) .Conclusion These data indicate that antioxidants N-acetyl-L-cysteine and catalase, possibly through regulation of the activity of caspase-3, can prevent lens opacification and apoptosis of lens epithelial cells.