title: Neuroprotective effects of N-acetylcysteine amide on experimental focal penetrating brain injury in rats.
abstract: We examined the effects of N-acetylcysteine amide (NACA) in the secondary inflammatory response following a novel method of focal penetrating traumatic brain injury (TBI) in rats. N-acetylcysteine (NAC) has limited but well-documented neuroprotective effects after experimental central nervous system ischemia and TBI, but its bioavailability is very low. We tested NACA, a modified form of NAC with higher membrane and blood-brain barrier permeability. Focal penetrating TBI was produced in male Sprague-Dawley rats randomly selected for NACA treatment (n=5) and no treatment (n=5). In addition, four animals were submitted to sham surgery. After 2 hours or 24 hours the brains were removed, fresh frozen, cut in 14 μm coronal sections and subjected to immunohistochemistry, immunofluorescence, Fluoro-Jade and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) analyses. All treated animals were given 300 mg/kg NACA intraperitoneally (IP) 2 minutes post trauma. The 24 hour survival group was given an additional bolus of 300 mg/kg IP after 4 hours. NACA treatment decreased neuronal degeneration by Fluoro-Jade at 24 hours with a mean change of 35.0% (p<0.05) and decreased TUNEL staining indicative of apoptosis at 2 hours with a mean change of 38.7% (p<0.05). Manganese superoxide dismutase (MnSOD) increased in the NACA treatment group at 24 hours with a mean change of 35.9% (p<0.05). Levels of migrating macrophages and activated microglia (Ox-42/CD11b), nitric oxide-producing inflammatory enzyme iNOS, peroxynitrite marker 3-nitrotyrosine, NFκB translocated to the nuclei, cytochrome C and Bcl-2 were not affected. NACA treatment decreased neuronal degeneration and apoptosis and increased levels of antioxidative enzyme MnSOD. The antiapoptotic effect was likely regulated by pathways other than cytochrome C. Therefore, NACA prevents brain tissue damage after focal penetrating TBI, warranting further studies towards a clinical application.
authors.affiliation: Department of Neuroscience, Karolinska Institutet, Retzius väg 8, B1:5, Stockholm SE-171 77, Sweden. Electronic address: mattias.gunther@ki.se.
authors.forename: Mattias
authors.initials: M
authors.lastname: Günther
authors.affiliation: Department of Applied Mechanics, Division of Vehicle Safety, Chalmers University of Technology, Gothenburg, Sweden.
authors.forename: Johan
authors.initials: J
authors.lastname: Davidsson
authors.affiliation: Department of Neuroscience, Karolinska Institutet, Retzius väg 8, B1:5, Stockholm SE-171 77, Sweden.
authors.forename: Stefan
authors.initials: S
authors.lastname: Plantman
authors.affiliation: Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Svante
authors.initials: S
authors.lastname: Norgren
authors.affiliation: Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Tiit
authors.initials: T
authors.lastname: Mathiesen
authors.affiliation: Department of Neuroscience, Karolinska Institutet, Retzius väg 8, B1:5, Stockholm SE-171 77, Sweden.
authors.forename: Mårten
authors.initials: M
authors.lastname: Risling
mesh_terms: D000111:Acetylcysteine / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001921:Brain / Q000187:drug effects / Q000503:physiopathology; D001930:Brain Injuries / Q000473:pathology*; D020197:Head Injuries, Penetrating / Q000473:pathology; D020287:In Situ Nick-End Labeling; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018696:Neuroprotective Agents; C487056:N-Acetylcysteinamide; D000111:Acetylcysteine
keywords: Inflammation; N-acetylcysteine amide; Neuroprotection; Sprague–Dawley; Traumatic brain injury