ABSTRACT
PURPOSE: The present work compared the behavioral outcomes of ACCS therapy delivered either intravenously (i.v.) or intracerebroventricularly (i.c.v.) after penetrating ballistic-like brain injury (PBBI). Histological markers for neuroinflammation and neurodegeneration were employed to investigate the potential therapeutic mechanism of ACCS. METHODS: Experiment-1, ACCS was administered either i.v. or i.c.v. for 1 week post-PBBI. Outcome metrics included behavioral (rotarod and Morris water maze) and gross morphological assessments. Experiment-2, rats received ACCS i.c.v for either 1 or 2 weeks post-PBBI. The inflammatory response was determined by immunohistochemistry for neutrophils and microglia reactivity. Neurodegeneration was visualized using silver staining. RESULTS: Both i.v. and i.c.v. delivery of ACCS improved motor outcome but failed to improve cognitive outcome or tissue sparing. Importantly, only i.c.v. ACCS treatment produced persistent motor improvements at a later endpoint. The i.c.v. ACCS treatment significantly reduced PBBI-induced increase in myeloperoxidase (MPO) and ionized calcium binding adaptor molecule 1 (Iba1) expression. Concomitant reduction of both Iba1 and silver staining were detected in corpus callosum with i.c.v. ACCS treatment. CONCLUSIONS: ACCS, as a treatment for TBI, showed promise with regard to functional (motor) recovery and demonstrated strong capability to modulate neuroinflammatory responses that may underline functional recovery. However, the majority of beneficial effects appear restricted to the i.c.v. route of ACCS delivery, which warrants future studies examining delivery routes (e.g. intranasal delivery) which are more clinically viable for the treatment of TBI.
Subject(s)
Cytokines/administration & dosage , Head Injuries, Penetrating/drug therapy , Motor Activity/drug effects , Neuroimmunomodulation/drug effects , Neuroprotective Agents/administration & dosage , Amnion , Animals , Brain/drug effects , Brain/pathology , Brain/physiopathology , Calcium-Binding Proteins/metabolism , Disease Models, Animal , Head Injuries, Penetrating/pathology , Head Injuries, Penetrating/physiopathology , Immunohistochemistry , Male , Maze Learning/drug effects , Maze Learning/physiology , Microfilament Proteins/metabolism , Motor Activity/physiology , Neuroimmunomodulation/physiology , Peroxidase/metabolism , Random Allocation , Rats, Sprague-Dawley , Rotarod Performance Test , SolutionsABSTRACT
Abstract Blood-brain barrier (BBB) disruption is a pathological hallmark of severe traumatic brain injury (TBI) and is associated with neuroinflammatory events contributing to brain edema and cell death. The goal of this study was to elucidate the profile of BBB disruption after penetrating ballistic-like brain injury (PBBI) in conjunction with changes in neuroinflammatory markers. Brain uptake of biotin-dextran amine (BDA; 3 kDa) and horseradish peroxidase (HRP; 44 kDa) was evaluated in rats at 4 h, 24 h, 48 h, 72 h, and 7 days post-PBBI and compared with the histopathologic and molecular profiles for inflammatory markers. BDA and HRP both displayed a uniphasic profile of extravasation, greatest at 24 h post-injury and which remained evident out to 48 h for HRP and 7 days for BDA. This profile was most closely associated with markers for adhesion (mRNA for intercellular adhesion molecule-1) and infiltration of peripheral granulocytes (mRNA for matrix metalloproteinase-9 [MMP-9] and myeloperoxidase staining). Improvement of BBB dysfunction coincided with increased expression of markers implicated in tissue remodeling and repair. The results of this study reveal a uniphasic and gradient opening of the BBB after PBBI and suggest MMP-9 and resident inflammatory cell activation as candidates for future neurotherapeutic intervention after PBBI.
