title: Retinoic acid induces apoptosis in activated canine neutrophils.
abstract: Activated neutrophils live longer, produce toxic metabolites and cause considerable tissue injury, which is central to the pathogenesis of many inflammatory conditions. Retinoids are a class of lipophilic compounds with anti-inflammatory effects. We examined the effect of retinoic acid on apoptosis in normal and activated neutrophils. Our results showed that treatment with 1 μg/ml Escherichia coli lipopolysaccharide (LPS) for 12 and 36 h delayed the spontaneous neutrophil apoptosis compared to untreated cells. But exposure of LPS-treated cells to retinoic acid (1 and 5 μM) abolished the inhibitory effects of LPS on neutrophil apoptosis in a concentration-dependent manner based on annexin V staining, Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, light and electron microscopy. These results show that retinoic acid increases apoptosis in activated canine neutrophils and this effect could enhance the resolution of inflammation in vivo.
authors.affiliation: Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N5B4, Canada.
authors.forename: Shankaramurthy
authors.initials: S
authors.lastname: Channabasappa
authors.affiliation: Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N5B4, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Stewart
authors.affiliation: Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N5B4, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Caldwell
authors.affiliation: Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N5B4, Canada.
authors.forename: Anthony
authors.initials: A
authors.lastname: Carr
authors.affiliation: Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N5B4, Canada. Electronic address: baljit.singh@usask.ca.
authors.forename: Baljit
authors.initials: B
authors.lastname: Singh
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D004285:Dogs; D020287:In Situ Nick-End Labeling; D008070:Lipopolysaccharides / Q000494:pharmacology; D018375:Neutrophil Activation; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D000893:Anti-Inflammatory Agents; D008070:Lipopolysaccharides; D014212:Tretinoin
keywords: Annexin-V; Apoptosis; Electron microscopy; Retinoic acid; TUNEL