title: Oxidative DNA damage is involved in cigarette smoke-induced lung injury in rats.
abstract: OBJECTIVE
  Reactive oxygen species (ROS) induced by exogenous toxicants are suggested to be involved in carcinogenesis by oxidative modification of DNA. 8-Hydroxyl-2-deoxyguanosine (8-OHdG) has been considered as a reliable biomarker for oxidative DNA damage both in vivo and in vitro studies. But the effect of smoking on oxidative damage has not yet been fully elucidated.
  
  
  METHODS
  Wistar rats were exposed to cigarette smoke at concentrations of 20 and 60 % for 30 min, twice/day for 45 weeks. Then the histopathology of lung tissues, levels of ROS, 8-OHdG, and total antioxidant (T-AOC), expression of DNA repair enzymes, e.g. 8-oxyguaine DNA glycosylase (OGG1), and MutThomolog 1 (Oxidized Purine Nucleoside Triphosphatase, MTH1) were determined in urine, peripheral blood lymphocytes, and lung tissue.
  
  
  RESULTS
  The results showed that long-term cigarette smoke exposure can cause obvious damages of lung tissue in rats. In addition, a significant and cigarette smoke concentration-dependent increase in ROS and 8-OHdG were observed compared with the non-exposed control rats. In contrast, the expression of OGG1 and MTH1, and T-AOC levels were obviously decreased after long-term exposure to cigarette smoke.
  
  
  CONCLUSIONS
  These findings indicate that long-term exposure to cigarette smoker increases ROS levels, decreases total antioxidant capacity, and interferes DNA repair capacity that eventually induces oxidative DNA damage, which appears to play an important role in cigarette smoke-induced lung injury in rats, and determination of 8-OHdG levels might be a useful method for monitoring oxidative damage in cigarette smokers.
authors.affiliation: Department of Toxicology, Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Medical College of Soochow University, 215123, Suzhou, China.
authors.forename: Zhihai
authors.initials: Z
authors.lastname: Chen
authors.forename: Dapeng
authors.initials: D
authors.lastname: Wang
authors.forename: Xing
authors.initials: X
authors.lastname: Liu
authors.forename: Weiwei
authors.initials: W
authors.lastname: Pei
authors.forename: Jianxiang
authors.initials: J
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Yan
authors.initials: Y
authors.lastname: An
authors.forename: Jihua
authors.initials: J
authors.lastname: Nie
authors.forename: Jian
authors.initials: J
authors.lastname: Tong
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D015415:Biomarkers / Q000097:blood / Q000378:metabolism / Q000652:urine; D004249:DNA Damage; D045647:DNA Glycosylases / Q000097:blood / Q000378:metabolism / Q000652:urine; D045643:DNA Repair Enzymes / Q000097:blood / Q000378:metabolism* / Q000652:urine; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism / Q000652:urine; D004305:Dose-Response Relationship, Drug; D055370:Lung Injury / Q000139:chemically induced*; D008214:Lymphocytes / Q000187:drug effects; D010084:Oxidation-Reduction; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000097:blood / Q000378:metabolism* / Q000652:urine; D012906:Smoke / Q000009:adverse effects; D062789:Tobacco Products / Q000633:toxicity*
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D017382:Reactive Oxygen Species; D012906:Smoke; D000080242:8-Hydroxy-2'-Deoxyguanosine; D045647:DNA Glycosylases; C483741:OGG1 protein, rat; D045643:DNA Repair Enzymes; D003849:Deoxyguanosine