彗星试验检测紫外线暴露后人淋巴细胞DNA修复能力

目的　用彗星试验评价人紫外线暴露后淋巴细胞DNA修复能力。方法　男女各 6名供血者 (2 6岁 )的淋巴细胞分成 3组 :紫外线 (UVC)组、UVC加新生霉素 (NOV)组、UVC加阿非迪霉素(APC)组。UVC波长 2 5 4nm ,照射剂量为 1.5J m2 ,于照射前和照射后 30、6 0、90、12 0、180、2 4 0min用彗星试验检测上述 3组DNA单链断裂 (SSB) ,计算DNA修复率 (DRR) ,用DRR评价 3组样本的修复能力。结果　 3组样本彗星平均尾长 (MTL)最大值主要出现于UVC照射后 90min。UVC组DRR范围为6 2 .84 %～ 98.71% ,平均为 81.84 % ,男女性别差异无显著性 (P >0 .0 5 )。NOV和APC组的平均DRR分别为 5 2 .98%和 39.5 7% ,明显低于UVC组 ,差异有显著性 (P <0 .0 1)。结论　彗星试验是一种快速、简便测定DNA修复能力的方法 ,DRR可反映个体DNA修复能力。

Detecting DNA repair capacity of human lymphocytes exposed to ultraviolet C with comet assay

OBJECTIVE: To assess DNA repair capacity of human lymphocytes with comet assay. METHODS: Fresh lymphocytes form twelve 26-year old donors (6 males, 6 females) were exposed to ultraviolet C (UVC, 254 nm) at the dose rate of 1.5 J/m(2). The lymphocytes of each donor were divided into three parts: UVC group, UVC + aphidicolin (APC) group, UVC + novobiocin (NOV) group. DNA single strand breaks were detected with comet assay in UVC-irradiated cells and unirradiated cells incubated for 30, 60, 90, 120, 180 and 240 min. DNA repair rate (DRR) was calculated and served as an indicator of DNA repair capacity. RESULTS: The maximum average comet tail length (MTL) in three groups appeared 90 min after UVC exposure. The DRR range of UVC group was 81.84% (62.84% - 98.71%); There was no significant difference in DRR between males and females (P > 0.05). However, the average DRRs of UVC + NOV group and UVC + APC group (52.98% and 39.57% respectively) were significantly lower than that of UVC group (P < 0.01). CONCLUSION: Comet assay is a rapid and simple screening test to assess DNA repair capacity. DRR, as an indicator, may express the individual DNA repair capacity.