title: Acute solvent exposure induced activation of cytochrome P4502E1 causes proximal tubular cell necrosis by oxidative stress.
abstract: Deliberate exposure to solvents has been associated with kidney disorders. However, the mechanism by which solvents induce renal damage after acute exposure has not been studied. Proximal tubular cell (LLC-PK1) cytotoxicity after exposure for 48 h to either 5 mM of p-xylene (XY) or toluene (TL) was compared to control (C) by cell viability (MTS assay), LDH release, DNA fragmentation, and malondialdehyde (MDA) release. CYP2E1 activity with or without a free radical scavenger (catalase-CT), or the CYP2E1 inhibitor disulfiram (DSF), was examined. Both p-xylene and toluene significantly reduced cell viability (XY 53.9 8+/-1.6 vs TL 54.8+/-0.9 vs C 102.7+/-2.1), increased CYP2E1 activity (mM/mg protein/min) (XY 3.6+/-0.5 vs TL 3.7+/-0.7 vs C 1.3+/-0.4) and MDA release (microM/mg protein) (XY 29.1+/-3.9 vs TL 12.3+/-1.4 vs C 2.8+/-0.3). LDH was increased (XY 59.9+/-3.0 vs TL 27.6+/-0.5 vs C 8.4+/-1.2), but there was no significant change in DNA fragmentation (OD/mg protein) suggesting necrosis as the predominant mode of cell death. DSF significantly attenuated CYP2E1 activity (XY+DSF 1.4+/-0.9, TL+DSF 2.3+/-0.1), LDH release (XY+DSF 45.1+/-2.0, TL+DSF 13.0+/-0.2) and MDA release (XY+DSF 4.3+/-0.5, TL+CT 6.2+/-1.1). Moreover, CT attenuated LDH release (XY+CT 36.4+/-5.1, TL+DSF 15.6+/-0.5) and MDA release (XY+DSF 5.4+/-0.7, TL+DSF 6.6+/-1.3) in XY and TL treated cells. This study confirms the pivotal role of CYP2E1 in solvent-induced oxidative stress and necrosis in proximal tubular cells after exposure to solvent at 5 mM for 48 h.
authors.affiliation: Department of Experimental Medicine , St. Bartholomew's and Royal London Medical School, Suite 22, Dominion House, 59 Bart's Close, EC1A 7BE, London, UK. s_alghamdi@go.com
authors.forename: Saeed S
authors.initials: SS
authors.lastname: Al-Ghamdi
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Raftery
authors.forename: Muhammad M
authors.initials: MM
authors.lastname: Yaqoob
mesh_terms: D018929:Cell Culture Techniques; D002470:Cell Survival; D019392:Cytochrome P-450 CYP2E1 / Q000494:pharmacology*; D006801:Humans; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects* / Q000473:pathology*; D009336:Necrosis; D018384:Oxidative Stress; D014050:Toluene / Q000633:toxicity*; D014992:Xylenes / Q000633:toxicity*
chemical_list: D014992:Xylenes; D014050:Toluene; C031286:4-xylene; D019392:Cytochrome P-450 CYP2E1