title: Evaluation of differential cytotoxic effects of the oil spill dispersant Corexit 9500.
abstract: OBJECTIVE
  The British Petroleum (BP) oil spill has raised several ecological and health concerns. As the first response, BP used a chemical dispersant, Corexit-9500, to disperse the crude oil in the Gulf of Mexico to limit shoreline contamination problems. Nevertheless, portions of this oil/Corexit mixture reached the shoreline and still remain in various Gulf shore environments. The use of Corexit itself has become a significant concern since its impacts on human health and environment is unclear.
  
  
  METHODS
  In this study, in vitro cytotoxic effects of Corexit were evaluated using different mammalian cells.
  
  
  RESULTS
  Under serum free conditions, the LC50 value for Corexit in BL16/BL6 cell was 16 ppm, in 1321N1 cell was 33 ppm, in H19-7 cell was 70 ppm, in HEK293 was 93 ppm, and in HK-2 cell was 95 ppm. With regard to the mechanisms of cytotoxicity, we hypothesize that Corexit can possibly induce cytotoxicity in mammalian cells by altering the intracellular oxidative balance and inhibiting mitochondrial functions. Corexit induced increased reactive oxygen species and lipid peroxide levels; also, it depleted glutathione content and altered catalase activity in H19-7 cells. In addition, there was mitochondrial complex-I inhibition and increase in the pro-apoptotic factors including caspase-3 and BAX expression.
  
  
  CONCLUSIONS
  The experimental results show changes in intracellular oxidative radicals leading to mitochondrial dysfunctions and apoptosis in Corexit treatments, possibly contributing to cell death. Our findings raise concerns about using large volumes of Corexit, a potential environmental toxin, in sensitive ocean environments.
authors.affiliation: Department of Civil Engineering, 212 Harbert Engineering Center, Auburn University, Auburn, AL, USA.
authors.forename: Mengyuan
authors.initials: M
authors.lastname: Zheng
authors.affiliation: Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA.
authors.forename: Manuj
authors.initials: M
authors.lastname: Ahuja
authors.affiliation: Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA.
authors.forename: Dwipayan
authors.initials: D
authors.lastname: Bhattacharya
authors.affiliation: Department of Civil Engineering, 212 Harbert Engineering Center, Auburn University, Auburn, AL, USA.
authors.forename: T Prabhakar
authors.initials: TP
authors.lastname: Clement
authors.affiliation: Department of Civil Engineering, 212 Harbert Engineering Center, Auburn University, Auburn, AL, USA.
authors.forename: Joel S
authors.initials: JS
authors.lastname: Hayworth
authors.affiliation: Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA. Electronic address: dhanamu@auburn.edu.
authors.forename: Muralikrishnan
authors.initials: M
authors.lastname: Dhanasekaran
mesh_terms: D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D006801:Humans; D007928:Lethal Dose 50; D015227:Lipid Peroxidation / Q000187:drug effects; D008055:Lipids / Q000633:toxicity*; D008928:Mitochondria / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D008055:Lipids; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; C470995:corexit 9500
keywords: Apoptosis; Corexit; Environmental toxicity; Gulf oil spill; Mitochondrial dysfunction; Oxidative stress