目的 对亚硒酸钠诱导白内障大鼠采用N-乙酰半胱氨酸进行预防性治疗，探讨N-乙酰半胱氨酸对白内障大鼠模型氧化损伤和晶状体浑浊程度的影响。方法 30只SD乳鼠随机分为3组，模型组ip 3.46 mg/kg亚硒酸钠溶液造模后，ip 0.1 mL/10 g生理盐水；实验组ip N-乙酰半胱氨酸10 mg/g，30 min ip亚硒酸钠溶液造模；对照组ip 0.1 mL/10 g生理盐水。所有动物均为隔日注射，连续6次。比较大鼠晶状体浑浊程度和SOD活性、NOS活性和MDA水平。结果 在晶状体核区、后囊区、前囊区+后囊区、前囊区+皮质区+核区+后囊区中，实验组与模型组比较得分差异具有统计学意义（P<0.05）；实验组SOD活性和MDA活性与模型组比较差异均具有统计学意义（P<0.05）。结论 N-乙酰半胱氨酸能够预防后囊和核区白内障的发生，其作用是通过减少MDA水平、提高SOD活性、改善氧化应激实现的。

Objective To use N-acetylcysteine for preventive treatment of cataract in rats induced by sodium selenite, and to investigate the preventive effect of N-acetylcysteine on oxidative damage and degree of lens opacity in cataract model of rats. Methods Thirty SD rats were randomly divided into three groups, the rats in model group were ip injected with 3.46 mg/kg sodium selenite for modeling, then 0.1 mL/10 g ip injection of physiological saline; The rats in experimental group received ip injection of N-acetylcysteine 10 mg/g, 30 min ip injection of sodium selenite for modeling; The rats in control group were ip injected with 0.1 mL/10 g of saline. All rats were injected every other day, 6 times in a row. The lens turbidity degree, SOD activity, NOS activity, and MDA level of rats were compared. Results In the lens nucleus, posterior capsule, anterior capsular area + posterior capsular area, anterior capsular area, and cortex + core + posterior capsule area, the difference of score of the experimental group between the model group were statistically significant (P < 0.05). Compared with the model group, the difference of SOD and MDA activity of the experiment group was statistically significant (P < 0.05). Conclusion N-acetylcysteine can prevent posterior and nucleus cataract, and its mechanism may be realized by reducing the content of MDA, increasing the activity of SOD, and improving the oxidative stress.