光催化剂TiO2对牛晶状体上皮细胞作用的实验研究

目的研究经长波紫外线（UVA）激发后光催化剂二氧化钛（TiO2）对细胞的杀伤作用和机制，探讨光催化剂TiO2应用于防治后发性白内障的可能性。方法将牛晶状体上皮细胞（lens epithelial cells,LEC）与不同浓度的TiO2共同孵育。按TiO2浓度分为对照组（0 μg／ml）和实验组（100μg／ml、150μg／ml和200μg／ml）,分别予UVA激发0、20、30和40min。采用MTT比色法测定经UVA激发的TiO2对牛LEC的杀伤效应。按TiO2浓度分为对照组（0μg／ml）和实验组（200μg／ml）。对照组UVA激发0、40min，实验组UVA激发0、30和40min。采用DNA琼脂糖凝胶电泳探讨光催化杀伤机制。按TiO2浓度分为对照组（0μg／ml）和实验组（200μg／ml）。分别予UVA激发0和30min。采用电镜技术观察光催化后细胞形态学变化。结果MTT比色法测定结果：在UVA激发下，TiO2对牛LEC杀伤率随着TiO2浓度增加和激发时间延长而增加，TiO2作用浓度达到150μg／ml且激发时间超过30min或浓度达到200μg／ml，其杀伤作用与相同UVA激发时间对照组相比，差异有统计学意义。200μg／ml TiO2组照射30min以上．提取DNA进行琼脂糖凝胶电泳显示,样品电泳迁移速率大于对照组,并在电镜下观察到大量细胞有坏死超微结构改变。结论在UVA的激发下,光催化剂TiO2可以明显杀伤牛LEC,杀伤效应具有时效和量效关系。TiO2的应用可能成为防治后发性白内障的新途径。

Experimental study of the effect of photocatalyst TiO2 on bovine lens epithelial cells

Objective To study the effect and mechanisms of photoeatalyst TiO2 on bovine lens epithelial cells （LECs） irradiated by uhraviolet-A （UVA） and to investigate the possibility of prevent- ing posterior capsule opacification （PCO）. Methods By culturing bovine LECs with different concentrations of TiO2 （0 μg/ml, 100 μg/ml, 150 μg/ml and 200 μg/ml） and irradiating with UVA for different lengths of time （0, 20. 30 and 40 min）, the photoexeitation effect of TiO, was evaluated with MTT Colorimetric Assay. DNA agarose gel eleetrophoresis was performed on the control group irradiated by UVA for 0 and 40 min and on the 200 μg/ml TiO2 group irradiated by UVA for 0, 30 and 40 min. An electron microseope was used to detect changes to the uhrastructure nf the control group and the 200 μg/ml TiO2 group irradiated by UVA for 0 and 30 rain. Results The photoexeitation effect of TiO2 on LECs was correlated with the concentrations of TiO2 and irradiation times as revealed by MTT Colorimetric Assay. There was a statistically significant difference in the destructive effect when the control group was compared to the experimental group with concentrations of TiO2 above 150 μg/ml and irradiated by UVA longer than 30 min, including the group with a concentration of TiO2 over 200 μg/ ml. DNA agarose gel electrophoresis showed that the DNA samples in the 200 μg/ml TiO2 group irradiated longer than 30 min were moving faster than that in the control group and the correspondent cell samples showed necrotic changes in the uhrastructure under electron microscope. Conclusion The significant destructive effect of photocatalyst TiO2 irradiated by UVA is both dose-dependent and time-dependent. This finding suggests a new possible method to treat PCO.