原花青素对MNNG致DNA损伤及拓扑异构酶Ⅱ的影响

目的　观察原花青素对DNA损伤的保护作用及对黑色素瘤细胞中拓扑异构酶的影响 ,探讨原花青素癌化学预防的作用机制。方法　单细胞电泳法检测羟自由基对L92 9细胞DNA损伤的尾迹 ,用 [H3]TdR参入细胞DNA中进行标记 ,测定上清液中的放射强度来判定MNNG对DNA损伤 ;从黑色素瘤肿瘤细胞中提取拓扑异构酶 ,用琼脂糖凝胶电泳测定活性。结果　原花青素可以减轻DNA损伤尾迹及MNNG对DNA的损伤。但对黑色素瘤肿瘤细胞中拓扑异构酶无抑制作用。结论　原花青素对羟自由基及致癌剂MNNG引起的细胞DNA损伤有一定的保护作用。但对拓扑异构酶的活性无抑制作用

Effect of procyanidins on carcinogen-induced DNA damage and topoisomerase

AIM To observed the effect of procyanidins on DNA damage induced by carcinogen or hydroxyl radical (OH·),and inhibitory effect on topoisomerase. METHODS Using labeled TdR uptake assay and single cell gel electrophonesis. Topoisomerase was extracted from B16F10 cell lines, used agarose gel electrophoresis assay. RESULTS It was showed that hydroxyl radical (OH·) or different doses of MNNG can induce severe DNA damage of L 929 cell lines. Procyanidins can alleviate the damage induced by MNNG or OH·. It shows certain dose dependent effect relationship . But there is no significant inhibitory against Topo Ⅱ activity by procyanidins even at a dose of 50 μmol·L -1 . CONCLUSION Procyanidins from grapes seeds can protect DNA damage,but not inhibit topoisomerase activity. This is one of cancer chemoprevention mechanism of Procyanidins.