Department of Physiology, Xiangya School of Medicine, Central South University, Changsha, Hunan, People's Republic of China.
Cell Biol Int. 2011 Mar;35(3):273-80. doi: 10.1042/CBI20090252.
Ozone may lead to DNA breaks in airway epithelial cells. p-ATM (phosphorylated ataxia telangiectasia mutated) plays a pivotal role in DNA repair. Derivatives of NO (nitric oxide) are regulators of the phosphorylation, and NO is increased under oxidative stress. The present study was aimed to study the effect of NO donor L-arg (L-arginine) on DNA damage repair in human bronchial epithelial cells exposed to ozone and the potential mechanisms involved. HBECs (human bronchial epithelial cells) were cultured with or without ozone (1.5 ppm, 30 min), DNA breaks were measured with a comet assay and agarose gel electrophoresis, cell cycling was determined by flow cytometry and p-ATM was measured by immunofluorescence and Western blot. Data were analysed by ANOVA (analysis of variance). P<0.05 was considered as significant. Ozone induced marked DNA breaks, G1-phase arrest and increased expression of p-ATM in HBECs, while wortmannin reduced the levels of p-ATM induced by ozone; the NO donor, L-arg, minimized the effects of ozone-induced DNA breaks and increased the level of p-ATM, while the NO synthase inhibitor, L-NMMA [N(G)-minomethyl-L-arginine], restrained those effects of L-arg. The effect of L-arg on DNA repair is NO-mediated, and p-ATM is implicated in the processes of DNA repair.
臭氧可能导致气道上皮细胞中的 DNA 断裂。p-ATM（共济失调毛细血管扩张突变相关蛋白激酶）在 DNA 修复中发挥关键作用。NO（一氧化氮）的衍生物是磷酸化的调节剂，在氧化应激下，NO 会增加。本研究旨在研究一氧化氮供体 L-arg（精氨酸）对暴露于臭氧的人支气管上皮细胞中 DNA 损伤修复的影响及其潜在机制。用或不用臭氧（1.5ppm，30 分钟）培养 HBEC（人支气管上皮细胞），用彗星试验和琼脂糖凝胶电泳测量 DNA 断裂，用流式细胞术测定细胞周期，用免疫荧光和 Western blot 测定 p-ATM。采用方差分析（ANOVA）进行数据分析。P<0.05 被认为具有统计学意义。臭氧诱导 HBEC 中明显的 DNA 断裂、G1 期停滞和 p-ATM 表达增加，而wortmannin 降低了臭氧诱导的 p-ATM 水平；NO 供体 L-arg 减轻了臭氧诱导的 DNA 断裂的影响，并增加了 p-ATM 的水平，而一氧化氮合酶抑制剂 L-NMMA[N（G）- 甲基-L-精氨酸]则抑制了 L-arg 的这些作用。L-arg 对 DNA 修复的影响是通过 NO 介导的，p-ATM 参与了 DNA 修复过程。
