Godschalk Roger, Curfs Daniëlle, Bartsch Helmut, Van Schooten Frederik-Jan, Nair Jagadeesan
German Cancer Research Center (DKFZ), Div. Toxicology and Cancer Risk Factors, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
Free Radic Res. 2003 Dec;37(12):1299-305. doi: 10.1080/10715760310001621333.
The genotoxic compound benzo[a]pyrene (B[a]P) enhances atherosclerotic plaque progression, possibly by inducing oxidative stress and subsequent lipid peroxidation (LPO). Since LPO plays a key role in atherosclerosis, stable LPO derived DNA modifications such as 1,N6-ethenodeoxy-adenosine (epsilondA) and 3,N4-ethenodeoxy-cytidine (epsilondC) may be useful biomarkers for in vivo oxidative stress. In this study, benzo[a]pyrene-diol-epoxide (BPDE)-DNA, epsilondA and epsilondC were determined by 32P-postlabelling in apolipoprotein E knockout (ApoE-KO) mice treated with 5mg/kg B[a]P by gavage. After 4 days, BPDE-DNA adduct levels were higher in aorta (10.8 +/- 1.4 adducts/10(8) nucleotides) than in lung (3.3 +/- 0.7, P < 0.05), which is a known target organ for B[a]P. Levels of epsilondA were higher in aorta of B[a]P-exposed animals than in unexposed controls (8.1 +/- 4.4 vs 3.4 +/- 2.1 adducts per 10(8) parent nucleotides, P < 0.05). On the other hand, epsilondC levels were not affected by B[a]P exposure. Serum low density lipoprotein (LDL) levels were lower in B[a]P-exposed mice than in controls (9.3 +/- 3.7 and 13.3 +/- 4.0mmol/l, respectively), whereas high density lipoprotein (HDL) levels were higher (1.4 +/- 1.6 and 0.4 +/- 0.3mmol/l, respectively). Consequently, a three-fold difference in the LDL/HDL ratio was observed (P = 0.001). epsilondA levels were positively related with plasma HDL concentrations (R = 0.68, P = 0.02), suggesting that the HDL mediated protection of the vessel wall against reactive lipid peroxides was reduced in B[a]P-exposed apoE-KO mice. Our observations show that direct as well as lipid peroxidation induced DNA damage is formed by B[a]P in aorta of apoE-KO mice, which may be involved in atherosclerotic plaque progression. This study further indicates that etheno-DNA adducts are useful biomarkers for in vivo oxidative stress in atherosclerosis.
基因毒性化合物苯并[a]芘（B[a]P）可促进动脉粥样硬化斑块进展，可能是通过诱导氧化应激及随后的脂质过氧化（LPO）来实现。由于LPO在动脉粥样硬化中起关键作用，稳定的LPO衍生的DNA修饰，如1,N6 - 乙烯基脱氧腺苷（εdA）和3,N4 - 乙烯基脱氧胞苷（εdC），可能是体内氧化应激的有用生物标志物。在本研究中，通过32P后标记法测定了经口灌胃给予5mg/kg B[a]P的载脂蛋白E基因敲除（ApoE-KO）小鼠体内的苯并[a]芘 - 二醇 - 环氧化物（BPDE）-DNA、εdA和εdC。4天后，主动脉中BPDE-DNA加合物水平（10.8±1.4个加合物/10(8)个核苷酸）高于肺（3.3±0.7，P<0.05），肺是B[a]P已知的靶器官。暴露于B[a]P的动物主动脉中εdA水平高于未暴露的对照组（每10(8)个亲本核苷酸中分别为8.1±4.4和3.4±2.1个加合物，P<0.05）。另一方面，εdC水平不受B[a]P暴露的影响。暴露于B[a]P的小鼠血清低密度脂蛋白（LDL）水平低于对照组（分别为9.3±3.7和13.3±4.0mmol/l），而高密度脂蛋白（HDL）水平较高（分别为1.4±1.6和0.4±0.3mmol/l）。因此，观察到LDL/HDL比值有三倍差异（P = 0.001）。εdA水平与血浆HDL浓度呈正相关（R = 0.68，P = 0.02），表明在暴露于B[a]P的ApoE-KO小鼠中，HDL介导的对血管壁免受活性脂质过氧化物损伤的保护作用降低。我们的观察结果表明，B[a]P在ApoE-KO小鼠主动脉中可导致直接的以及脂质过氧化诱导的DNA损伤，这可能与动脉粥样硬化斑块进展有关。本研究进一步表明，乙烯基DNA加合物是动脉粥样硬化体内氧化应激的有用生物标志物。
