菲啰啉对不同氧化剂和多柔比星所致CHL细胞DNA链断裂的影响

目的 为了研究菲啰啉对2种氧化剂和抗癌药多柔比星诱发细胞DNA损伤的影响, 并初步探讨其损伤机制。方法 用不同浓度菲啰啉预处理CHL细胞30 min, 再分别加入3种不同染毒受试物,共同培养一定时间(0.3 mmol·L^-1重铬酸钾：105 min； 0.5 μmol·L^-1多柔比星：5 min； 0.4 mmol·L^-1过氧化氢(H₂O₂)：25 min)后, 用碱性单细胞凝胶电泳方法(ASCGE)测定DNA链断裂情况, 并同时以菲啰啉与二甲亚砜(DMSO，0.33 mol·L^-1)比较对H₂O₂致DNA损伤中·OH的产生和清除。结果 3种染毒受试物均可明显引起CHL细胞DNA链断裂；而当3 μmol·L^-1菲啰啉预处理后, 可使重铬酸钾、H₂O₂所致DNA迁移长度和细胞拖尾率明显降低, 并超过DMSO降低H₂O₂的损伤作用, 当菲啰林浓度升至12 μmol·L^-1时, 可完全消除这两种因素所致的DNA链断裂损伤；10 μmol·L^-1菲啰啉可抑制多柔比星所致DNA损伤, 但浓度直至60 μmol·L^-1仍不能完全消除多柔比星的损伤作用。结论 菲啰啉对2种氧化剂和多柔比星所致DNA损伤均有不同程度的防护作用,同时提示重铬酸钾和H₂O₂所致的DNA损伤主要与需过渡金属离子参与的·OH产生有关, 而多柔比星所致损伤仅部分与此有关。

Effect of 1,10-phenanthroline on DNA strand breaks induced by different oxidants and doxorubicin in CHL cells

AIM To study the effect of 1,10-phenanthroline(OP) on DNA oxidative damage and explore the damage mechanism initially. METHODS CHL cells were pretreated with different concentration of OP for 30 min, then co cultured with two tested toxic oxidants and doxorubicin for certain time course(0.4 mmol·L^-1 hydrogen peroxide：25 min, 0.3 mmol·L^-1 potassium chromate： 105 min, 0.5 μmol·L^-1 doxorubicin： 75 min). OP was compared with dimethyl sulfoxide(DMSO) co-cultured with hydrogen peroxide to elucidate their inhibitory effect on DNA damage by hydrogen peroxide indirectly through prod uction and clearance of ·OH, finally alkaline single cell gel electrophoresis (ASCGE) assay was used to detect DNA strand breaks. RESULTS The DNA strand breaks were induced obviously after treated by 3 tested toxic agents respectively for certain time course. The DNA strand breaks induced by hydrogen perox ide or potassium chromate were antagonized completely by 12 μmol·L^-1 OP. OP 3－6 μmol·L^-1 is equal to DMSO 0.33 mol·L^-1 in protection against DNA strand breaks by hydrogen peroxide via ·OH. Treatment of CHL cells with 10 or 30 μmol·L^-1 OP resulted in a marked decrease in the DNA breaks induced by doxorubicin, but the DNA breaks still could not be antagonized completely when the concentration of OP up to 60 μmol·L^-1. CONCLUSION The treatment of CHL cells with OP resulted in a marked decrease in the DNA strand breaks caused by 3 tested toxic agents, i.e., OP has a protection from DNA damage. The results also suggest that the production of ·OH which closely related to the transition metal ion plays a major role in DNA damage induced by hydrogen peroxide or potassium chromate, but doxorubicin-induced DNA damage is only in part related to that.