title: Protective effects of N-acetylcysteine amide (NACA) on gentamicin-induced apoptosis in LLC-PK1 cells.
abstract: OBJECTIVE
  Apoptosis plays a critical role in the pathogenesis of gentamicin (Gen)-induced nephrotoxicity. However, the underlying molecular mechanisms still remain unclear. In this study, we addressed the role of p38 mitogen-activated protein kinase (MAPK)/inducible nitric oxide synthase (iNOS) signaling pathway in Gen-induced nephrotoxicity and evaluated the protective effect of the free-radical scavenger N-acetylcysteine amide (NACA).
  
  
  METHODS
  Pig kidney epithelial cells (LLC-PK1) cells were exposed to Gen for variable times and doses. Cytotoxicity was assessed by morphology and by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Protein expression was assessed by Western blotting.
  
  
  RESULTS
  Exposure to Gen-induced apoptosis in a dose-dependent and time-dependent manner was assessed by DNA content analysis and poly ADP ribose polymerase (PARP) cleavage. Gen caused increased phosphorylation of p38 MAPK and induction of iNOS. This was accompanied by a significant upregulation of Bax and nuclear factor κB (NF-κB) and a downregulation of Bcl-2 expression. Pretreatment with SB203580, aminoguanidine (AG), and NACA inhibited apoptosis. Furthermore, pretreatment with SB203580 and NACA not only attenuated the pro-apoptotic effect of Gen, but also significantly reversed its effects on p38 MAPK phosphorylation and iNOS induction. The Gen-induced effects on Bcl-2, Bax, and NF-κB expression were also reversed by SB203580, AG, and NACA.
  
  
  CONCLUSIONS
  In conclusion, NACA can attenuate Gen-induced apoptotic injury in LLC-PK1 cells through inhibiting p38 MAPK/iNOS signaling pathway.
authors.affiliation: Division of Pediatric Nephrology, Department for Clinical Science, Intervention and Technology, Karolinska Institutet, Karolinska University Hospital Huddinge, Stockholm, Sweden. gxzdoctor@yahoo.com.cn
authors.forename: Xuezhong
authors.initials: X
authors.lastname: Gong
authors.forename: Gianni
authors.initials: G
authors.lastname: Celsi
authors.forename: Katarina
authors.initials: K
authors.lastname: Carlsson
authors.forename: Svante
authors.initials: S
authors.lastname: Norgren
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D058186:Acute Kidney Injury / Q000201:enzymology / Q000473:pathology / Q000517:prevention & control*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D015153:Blotting, Western; D002470:Cell Survival; D002478:Cells, Cultured; D004247:DNA / Q000235:genetics; D004195:Disease Models, Animal; D005434:Flow Cytometry; D016166:Free Radical Scavengers / Q000494:pharmacology; D005786:Gene Expression Regulation; D005839:Gentamicins / Q000633:toxicity; D018374:LLC-PK1 Cells / Q000187:drug effects / Q000201:enzymology / Q000473:pathology; D016328:NF-kappa B / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics; D052247:Nitric Oxide Synthase Type II; D016133:Polymerase Chain Reaction; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000096:biosynthesis / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D013552:Swine; D051028:bcl-2-Associated X Protein / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics; D048051:p38 Mitogen-Activated Protein Kinases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D016166:Free Radical Scavengers; D005839:Gentamicins; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; C487056:N-Acetylcysteinamide; D004247:DNA; D052247:Nitric Oxide Synthase Type II; D048051:p38 Mitogen-Activated Protein Kinases; D000111:Acetylcysteine