外源核苷酸对受损小鼠胸腺细胞DNA修复的影响  

Effect of exogenous nucleotides on repair of damaged DNA in mouse thymocytes

作　　者：王兰芳[1] 乐国伟[2] 戴秋萍[1] 

机构地区：[1]同济大学基础医学院预防医学教研室,上海200092 [2]江南大学教育部食品科学与安全重点实验室,江苏无锡214036

出　　处：《第四军医大学学报》2007年第7期613-615,共3页Journal of the Fourth Military Medical University

基　　金：教育部高校骨干教师资助项目(G0202)

摘　　要：目的:探讨外源核苷酸对受损小鼠胸腺细胞DNA修复的影响.方法:采用10μmol/L的N-甲基-N-硝基-N亚硝基胍(MNNG)诱导小鼠胸腺细胞DNA损伤后,在终浓度分别为0,0.1,1和10mmol/L核苷酸的RPMI-1640基础培养基或完全培养基中培养,在培养的第2,5h采用单细胞凝胶电泳技术分析细胞DNA损伤和修复情况.结果:培养2h时,基础培养基中各组间的拖尾细胞百分率差异无统计学意义(P>0.05);完全培养基中核苷酸能降低拖尾率(P<0.01).5h时,随着核苷酸添加浓度的升高,拖尾率均降低(P<0.01).在相同的培养基中,各组的彗星尾长在2h差异无统计学意义(P>0.05),5h后,在基础培养基中添加1,10mmol/L的核苷酸使得彗星尾长降低(P<0.05);在完全培养基中添加1,10mmol/L的核苷酸也使得彗星尾长降低(P<0.01).在培养的2～5h内,补充核苷酸均能提高基础培养基(P<0.05)和完全培养基(P<0.01)中DNA修复细胞的百分率.结论:外源核苷酸能明显促进受损小鼠胸腺细胞DNA的修复,且核苷酸的作用与其添加水平有关.AIM： To investigate the effect of exogenous nucleotides on the repair of damaged DNA in mouse thymocytes in vitro. METHODS： Thymocytes from Kunming male mice were treated with N-methyl-N＇-nitro-N-nitrosoguanidine （MNNG, 10 umol/L） to induce DNA damage. DNA-damaged cells were cultured in basic or complete RPMI 1640 medium supplemented with different levels of nucleotides （0, 0. 1, 1, 10 mmol/L）. DNA damage and repair were analyzed at 2, 5 h with single-cell gel electrophoresis. RESULTS： Nucleotides had no significant effect on the percentage of comet ceils at 2 h in basic medium （P 〉 0.05 ）, but the percentage of comet cells decreased significantly in complete medium with nucleotides supplementation （ P 〈 0. 01 ）. The nucleotides supplementation significantly decreased the percentage of comet cells at 5 h （ P 〈 0.01 ）. Comet tail length had no significant difference among groups at 2 h in basic or complete medium （P 〉0.05）. Nucleotides of 1, 10 mmol/L decreased comet tail length at 5 h in basic medium （ P 〈0.01 ） . The supplementation of 1, 10 mmol/L nucleotides decreased comet tail length at 5 h in complete medium （P 〈 0.01 ）. The percentage of DNA-repaired cells was increased significantly with nucleotides supplementation between 2 and 5 h in basic （P 〈 0.05 ） or complete mediam （P 〈 0.01 ）. CONCLUSION： The supplementation of nucleotides can accelerate the repair of damaged DNA in mouse thymocytes in vitro. The effect of nucleotides is related with the supplemental levels of nucleotides.

关 键 词：核苷酸 DNA损伤 DNA修复 彗星试验 

分 类 号：R151.2[医药卫生—营养与食品卫生学]