光照核黄素损伤细胞端粒、端粒酶的变化

The effect of riboflavin photodegradation to cells' telomere and telomerase

目的:探讨核黄素的光敏作用对细胞端粒、端粒酶及生长活性的影响。方法:采用四甲基偶氮唑(MTT)法检测光照核黄素对Hela细胞的抑制率;细胞免疫组化法检测细胞8-羟基鸟嘌呤的生成;Southern B lot检测细胞端粒长度、端粒酶活性变化;结果:光照核黄素对Hela细胞有抑制作用且随浓度的增加抑制作用加强;受核黄素作用后细胞损伤产物8-羟基鸟嘌呤染色结果显示细胞核强阳性;细胞端粒随核黄素作用时间的延长有缩短的趋势,而端粒酶活性在开始的1h左右略有下降,而至后则有上升趋势。结论:核黄素光敏反应可造成细胞DNA富含鸟嘌呤区域羟基化损伤,该羟基化损伤与富含鸟嘌呤的端粒重复序列缩短有关。

Objective： For further research of the effect of photodegradation of riboflavin to cells. Methods： The mean telomere length and the activities of telomerase were studied. MTT assay was used to estimate the inhibition rate of riboflavin. Immnohistochemical studies by detecting 8-hydroxyguanine（8-oxodG） as the marker of DNA damage. The telomere length was measured by southern blot. The activities of telomerase was measured by TRAP. Results ：The result showed that The inhibition rate of tumor cells is dose-dependent of riboflavin; guanine could be oxidized into 8-hydroxyguanine in both 32 and 3.2μmol/L riboflavin- given groups ; the telomere length was measured by southern blot and the results indicated that there was a continuous telomere shortens with time; in the time of 0,0.5,1,2,4h dealt with photosensitiv riboflavin, ratio of telomere shorten was 5.5%, 11.2%, 14% ,17.8%. The activities of telomerase was lower＇at first lh but had a trend to rise after that. Conclusion：The photodegrada- tion of riboflavin caused oxidized damage of G-rich region on DNA, which may related with the telomere shortening and the activities of telomerase.