In vitro and in vivo studies on oxygen free radical and DNA adduct formation in rat lung and liver during benzo[a]pyrene metabolism
In vitro and in vivo studies on oxygen free radical and DNA adduct formation in rat lung and liver during benzo[a]pyrene metabolism
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DOI：
10.1080/10715760400000976
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发表时间：
2004-09-01
影响因子：
3.3
通讯作者：
Kleinjans, JCS
中科院分区：
文献类型：
--
作者：
Briedé, JJ;Godschalk, RWL;Kleinjans, JCS
活性氧 (ROS) 可能在苯并 (a) 芘 (B[a]P) 代谢转化过程中产生，可能参与 B[a]P 诱导的遗传毒性，并最终导致致癌性。因此，通过电子自旋共振 (ESR/EPR) 光谱法在体外研究了大鼠肺和肝微粒体的 ROS 形成，在与大鼠肺一起孵育时检测到 B[a]P 介导的 ROS 生成，但在肝微粒体中未检测到。非异构体特异性抑制剂 SKF-525A 对细胞色素 P450 (CYP450) 的抑制导致 B[a]P 依赖性 ROS 形成的完全抑制，而 ROS 形成不受吲哚美辛抑制前列腺素 H 合酶的影响。随后，在大鼠肺和肝脏中检测单次口服 B[a]P 后大体积 DNA 加合物的形成和 8-oxo-dG 水平，并结合 8-oxoG 的尿排泄。 B[a]P 暴露导致尿 8-oxo-dG 水平升高。相反，接触 B[a]P 后，肝脏和肺中的 8-oxo-dG 水平下降。大体积 DNA 加合物在大鼠肺中比在肝脏中达到更高水平并且更持久。这些结果表明，ROS 是在 B[a]P 的 CYP450 依赖性代谢过程中产生的，特别是在大鼠肺中，但这不一定会导致体内氧化性 DNA 损伤水平增加，可能是通过诱导 DNA 修复机制来实现的。
Reactive oxygen species (ROS), possibly produced during the metabolic conversion of benzo(a)pyrene (B[a]P), could be involved in B[a]P-induced genotoxicity and, eventually, carcinogenicity. Therefore, ROS formation by rat lung and liver microsomes was studied in vitro by electron spin resonance (ESR/EPR) spectrometry B[a]P-mediated generation of ROS was detected in incubations with rat lung, but not with liver microsomes. Inhibition of cytochrome P450 (CYP450) by the non isoform-specific inhibitor SKF-525A resulted in a complete inhibition of B[a]P-dependent ROS formation, whereas ROS formation was not affected by inhibition of prostaglandin H synthase by indomethacin. Subsequently, bulky DNA adduct formation and 8-oxo-dG levels after a single oral dose of B[a]P were examined in vivo in rat lung and liver, in combination with urinary excretion of 8-oxodG. B[a]P exposure resulted in increased urinary 8-oxo-dG levels. On the contrary, 8-oxo-dG levels decreased in liver and lung after B[a]P exposure. Bulky DNA adducts reached higher levels and were more persistent in rat lung than in liver. These results indicate that ROS are generated during the CYP450 dependent metabolism of B[a]P, particularly in the rat lung, but this does not necessarily result in increased levels of oxidative DNA damage in vivo, possibly by induction of DNA repair mechanisms.