1
|
Iannucci J, Dominy R, Bandopadhyay S, Arthur EM, Noarbe B, Jullienne A, Krkasharyan M, Tobin RP, Pereverzev A, Beevers S, Venkatasamy L, Souza KA, Jupiter DC, Dabney A, Obenaus A, Newell-Rogers MK, Shapiro LA. Traumatic brain injury alters the effects of class II invariant peptide (CLIP) antagonism on chronic meningeal CLIP + B cells, neuropathology, and neurobehavioral impairment in 5xFAD mice. J Neuroinflammation 2024; 21:165. [PMID: 38937750 PMCID: PMC11212436 DOI: 10.1186/s12974-024-03146-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 05/29/2024] [Indexed: 06/29/2024] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) is a significant risk factor for Alzheimer's disease (AD), and accumulating evidence supports a role for adaptive immune B and T cells in both TBI and AD pathogenesis. We previously identified B cell and major histocompatibility complex class II (MHCII)-associated invariant chain peptide (CLIP)-positive B cell expansion after TBI. We also showed that antagonizing CLIP binding to the antigen presenting groove of MHCII after TBI acutely reduced CLIP + splenic B cells and was neuroprotective. The current study investigated the chronic effects of antagonizing CLIP in the 5xFAD Alzheimer's mouse model, with and without TBI. METHODS 12-week-old male wild type (WT) and 5xFAD mice were administered either CLIP antagonist peptide (CAP) or vehicle, once at 30 min after either sham or a lateral fluid percussion injury (FPI). Analyses included flow cytometric analysis of immune cells in dural meninges and spleen, histopathological analysis of the brain, magnetic resonance diffusion tensor imaging, cerebrovascular analysis, and assessment of motor and neurobehavioral function over the ensuing 6 months. RESULTS 9-month-old 5xFAD mice had significantly more CLIP + B cells in the meninges compared to age-matched WT mice. A one-time treatment with CAP significantly reduced this population in 5xFAD mice. Importantly, CAP also improved some of the immune, histopathological, and neurobehavioral impairments in 5xFAD mice over the ensuing six months. Although FPI did not further elevate meningeal CLIP + B cells, it did negate the ability of CAP to reduce meningeal CLIP + B cells in the 5xFAD mice. FPI at 3 months of age exacerbated some aspects of AD pathology in 5xFAD mice, including further reducing hippocampal neurogenesis, increasing plaque deposition in CA3, altering microgliosis, and disrupting the cerebrovascular structure. CAP treatment after injury ameliorated some but not all of these FPI effects.
Collapse
Affiliation(s)
- Jaclyn Iannucci
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Reagan Dominy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Shreya Bandopadhyay
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - E Madison Arthur
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Brenda Noarbe
- Division of Biomedical Sciences, University of California Riverside, Riverside, CA, USA
| | - Amandine Jullienne
- Division of Biomedical Sciences, University of California Riverside, Riverside, CA, USA
| | - Margret Krkasharyan
- Division of Biomedical Sciences, University of California Riverside, Riverside, CA, USA
| | - Richard P Tobin
- Department of Surgery, Division of Surgical Oncology, University of Colorado Anschutz Medical Campus, Denver, CO, USA
| | - Aleksandr Pereverzev
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Samantha Beevers
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Lavanya Venkatasamy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Karienn A Souza
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA
| | - Daniel C Jupiter
- Department of Biostatistics and Data Science, Department of Orthopaedics and Rehabilitation, The University of Texas Medical Branch, Galveston, TX, USA
| | - Alan Dabney
- Department of Statistics, College of Arts & Sciences, Texas A&M University, College Station, TX, USA
| | - Andre Obenaus
- Division of Biomedical Sciences, University of California Riverside, Riverside, CA, USA
| | - M Karen Newell-Rogers
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA.
- Department of Medical Physiology, College of Medicine, Texas A&M University, Bryan, TX, USA.
| | - Lee A Shapiro
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University, Bryan, TX, USA.
| |
Collapse
|
2
|
Sabetta Z, Krishna G, Curry T, Adelson PD, Thomas TC. Aging with TBI vs. Aging: 6-month temporal profiles for neuropathology and astrocyte activation converge in behaviorally relevant thalamocortical circuitry of male and female rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.06.527058. [PMID: 36798182 PMCID: PMC9934568 DOI: 10.1101/2023.02.06.527058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Traumatic brain injury (TBI) manifests late-onset and persisting clinical symptoms with implications for sex differences and increased risk for the development of age-related neurodegenerative diseases. Few studies have evaluated chronic temporal profiles of neuronal and glial pathology that include sex as a biological variable. After experimental diffuse TBI, late-onset and persisting somatosensory hypersensitivity to whisker stimulation develops at one-month post-injury and persists to at least two months post-injury in male rats, providing an in vivo model to evaluate the temporal profile of pathology responsible for morbidity. Whisker somatosensation is dependent on signaling through the thalamocortical relays of the whisker barrel circuit made up of glutamatergic projections between the ventral posteromedial nucleus of the thalamus (VPM) and primary somatosensory barrel cortex (S1BF) with inhibitory (GABA) innervation from the thalamic reticular nucleus (TRN) to the VPM. To evaluate the temporal profiles of pathology, male and female Sprague Dawley rats ( n = 5-6/group) were subjected to sham surgery or midline fluid percussion injury (FPI). At 7-, 56-, and 168-days post-injury (DPI), brains were processed for amino-cupric silver stain and glial fibrillary acidic protein (GFAP) immunoreactivity, where pixel density of staining was quantified to determine the temporal profile of neuropathology and astrocyte activation in the VPM, S1BF, and TRN. FPI induced significant neuropathology in all brain regions at 7 DPI. At 168 DPI, neuropathology remained significantly elevated in the VPM and TRN, but returned to sham levels in the S1BF. GFAP immunoreactivity was increased as a function of FPI and DPI, with an FPI × DPI interaction in all regions and an FPI × Sex interaction in the S1BF. The interactions were driven by increased GFAP immunoreactivity in shams over time in the VPM and TRN. In the S1BF, GFAP immunoreactivity increased at 7 DPI and declined to age-matched sham levels by 168 DPI, while GFAP immunoreactivity in shams significantly increased between 7 and 168 days. The FPI × Sex interaction was driven by an overall greater level of GFAP immunoreactivity in FPI males compared to FPI females. Increased GFAP immunoreactivity was associated with an increased number of GFAP-positive soma, predominantly at 7 DPI. Overall, these findings indicate that FPI, time post-injury, sex, region, and aging with injury differentially contribute to chronic changes in neuronal pathology and astrocyte activation after diffuse brain injury. Thus, our results highlight distinct patterns of pathological alterations associated with the development and persistence of morbidity that supports chronic neuropathology, especially within the thalamus. Further, data indicate a convergence between TBI-induced and age-related pathology where further investigation may reveal a role for divergent astrocytic phenotypes associated with increased risk for neurodegenerative diseases.
Collapse
|
3
|
Griffiths DR, Matthew Law L, Young C, Fuentes A, Truran S, Karamanova N, Bell LC, Turner G, Emerson H, Mastroeni D, Gonzales RJ, Reaven PD, Chad Quarles C, Migrino RQ, Lifshitz J. Chronic Cognitive and Cerebrovascular Function after Mild Traumatic Brain Injury in Rats. J Neurotrauma 2022; 39:1429-1441. [PMID: 35593008 PMCID: PMC10870816 DOI: 10.1089/neu.2022.0015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Severe traumatic brain injury (TBI) results in cognitive dysfunction in part due to vascular perturbations. In contrast, the long-term vasculo-cognitive pathophysiology of mild TBI (mTBI) remains unknown. We evaluated mTBI effects on chronic cognitive and cerebrovascular function and assessed their interrelationships. Sprague-Dawley rats received midline fluid percussion injury (n = 20) or sham (n = 21). Cognitive function was assessed (3- and 6-month novel object recognition [NOR], novel object location [NOL], and temporal order object recognition [TOR]). Six-month cerebral blood flow (CBF) and cerebral blood volume (CBV) using contrast magnetic resonance imaging (MRI) and ex vivo circle of Willis artery endothelial and smooth muscle-dependent function were measured. mTBI rats showed significantly impaired NOR, with similar trends (non-significant) in NOL/TOR. Regional CBF and CBV were similar in sham and mTBI. NOR correlated with CBF in lateral hippocampus, medial hippocampus, and primary somatosensory barrel cortex, whereas it inversely correlated with arterial smooth muscle-dependent dilation. Six-month baseline endothelial and smooth muscle-dependent arterial function were similar among mTBI and sham, but post-angiotensin 2 stimulation, mTBI showed no change in smooth muscle-dependent dilation from baseline response, unlike the reduction in sham. mTBI led to chronic cognitive dysfunction and altered angiotensin 2-stimulated smooth muscle-dependent vasoreactivity. The findings of persistent pathophysiological consequences of mTBI in this animal model add to the broader understanding of chronic pathophysiological sequelae in human mild TBI.
Collapse
Affiliation(s)
- Daniel R. Griffiths
- Phoenix VA Health Care System, Phoenix, Arizona, USA
- University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, USA
- Barrow Neurological Institute at Phoenix Children’s Hospital, Phoenix, Arizona, USA
| | - L. Matthew Law
- Phoenix VA Health Care System, Phoenix, Arizona, USA
- University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, USA
- Barrow Neurological Institute at Phoenix Children’s Hospital, Phoenix, Arizona, USA
| | - Conor Young
- University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, USA
| | | | - Seth Truran
- Phoenix VA Health Care System, Phoenix, Arizona, USA
| | | | - Laura C. Bell
- Barrow Neurological Institute, Phoenix, Arizona, USA
| | | | | | | | - Rayna J. Gonzales
- University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, USA
| | - Peter D. Reaven
- Phoenix VA Health Care System, Phoenix, Arizona, USA
- University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, USA
| | | | - Raymond Q. Migrino
- Phoenix VA Health Care System, Phoenix, Arizona, USA
- University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, USA
| | - Jonathan Lifshitz
- Phoenix VA Health Care System, Phoenix, Arizona, USA
- University of Arizona College of Medicine – Phoenix, Phoenix, Arizona, USA
- Barrow Neurological Institute at Phoenix Children’s Hospital, Phoenix, Arizona, USA
| |
Collapse
|
4
|
Giordano KR, Law LM, Henderson J, Rowe RK, Lifshitz J. Time Course of Remote Neuropathology Following Diffuse Traumatic Brain Injury in the Male Rat. Exp Neurobiol 2022; 31:105-115. [PMID: 35673999 PMCID: PMC9194637 DOI: 10.5607/en21027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 12/15/2021] [Accepted: 04/12/2022] [Indexed: 11/19/2022] Open
Abstract
Traumatic brain injury (TBI) can affect different regions throughout the brain. Regions near the site of impact are the most vulnerable to injury. However, damage to distal regions occurs. We investigated progressive neuropathology in the dorsal hippocampus (near the impact) and cerebellum (distal to the impact) after diffuse TBI. Adult male rats were subjected to midline fluid percussion injury or sham injury. Brain tissue was stained by the amino cupric silver stain. Neuropathology was quantified in sub-regions of the dorsal hippocampus at 1, 7, and 28 days post-injury (DPI) and coronal cerebellar sections at 1, 2, and 7 DPI. The highest observed neuropathology in the dentate gyrus occurred at 7 DPI which attenuated by 28 DPI, whereas the highest observed neuropathology was at 1 DPI in the CA3 region. There was no significant neuropathology in the CA1 region at any time point. Neuropathology was increased at 7 DPI in the cerebellum compared to shams and stripes of pathology were observed in the molecular layer perpendicular to the cerebellar cortical surface. Together these data show that diffuse TBI can result in neuropathology across the brain. By describing the time course of pathology in response to TBI, it is possible to build the temporal profile of disease progression.
Collapse
Affiliation(s)
- Katherine R Giordano
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
| | - L Matthew Law
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
| | - Jordan Henderson
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA
| | - Rachel K Rowe
- Department of Integrative Physiology, University of Colorado, Boulder, CO 80309, USA
| | - Jonathan Lifshitz
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, AZ 85013, USA.,Department of Child Health, University of Arizona College of Medicine - Phoenix, Phoenix, AZ 85004, USA.,Phoenix Veterans Affairs Health Care System, Phoenix, AZ 85012, USA
| |
Collapse
|
5
|
Rabinowitz AR, Kumar RG, Sima A, Venkatesan UM, Juengst SB, O'Neil-Pirozzi TM, Watanabe TK, Goldin Y, Hammond FM, Dreer LE. Aging with Traumatic Brain Injury: Deleterious Effects of Injury Chronicity Are Most Pronounced in Later Life. J Neurotrauma 2021; 38:2706-2713. [PMID: 34082606 PMCID: PMC8822416 DOI: 10.1089/neu.2021.0038] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Understanding the effects of age on longitudinal traumatic brain injury (TBI) outcomes requires attention to both chronic and evolving TBI effects and age-related changes in health and function. The present study examines the independent and interactive effects of aging and chronicity on functional outcomes after TBI. We leveraged a well-defined cohort of individuals who sustained a moderate/severe TBI and received acute inpatient rehabilitation at specialized centers with high follow up rate as part of their involvement in the TBI Model Systems longitudinal study. We selected individuals at one of two levels of TBI chronicity (either 2 or 10 years post-injury) and used an exact matching procedure to obtain balanced chronicity groups based on age and other characteristics (N = 1993). We found that both older age and greater injury chronicity were related to greater disability, reduced functional independence, and less community participation. There was a significant age by chronicity interaction, indicating that the adverse effects of greater time post-injury were most pronounced among survivors who were age 75 or older. The inflection point at roughly 75 years of age was corroborated by post hoc analyses, dividing the sample by age at 75 years and examining the interaction between age group and chronicity. These findings point to a need for provision of rehabilitation services in the chronic injury period, particularly for those who are over 75 years old. Future work should investigate the underlying mechanisms of this interaction towards the goal of developing interventions and models of care to promote healthy aging with TBI.
Collapse
Affiliation(s)
| | - Raj G. Kumar
- Department of Rehabilitation and Human Performance, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Adam Sima
- Corrona, LLC, Waltham, Massachusetts, USA
| | | | - Shannon B. Juengst
- Department of Physical Medicine and Rehabilitation, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Applied Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Therese M. O'Neil-Pirozzi
- Department of Physical Medicine and Rehabilitation, Spaulding Rehabilitation Hospital, Boston, Massachusetts, USA
- Department of Communication Sciences and Disorders, Northeastern University, Charlestown, Massachusetts, USA
| | | | - Yelena Goldin
- Department of Cognitive Rehabilitation, Hackensack Meridian JFK University Medical Center, Edison, New Jersey, USA
- Department of Physical Medicine and Rehabilitation, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
| | - Flora M. Hammond
- Department of Physical Medicine and Rehabilitation, Indiana University School of Medicine Rehabilitation Hospital of Indiana, Indianapolis, Indiana, USA
| | - Laura E. Dreer
- Department of Ophthalmology and Visual Sciences, University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Physical Medicine and Rehabilitation, University of Alabama at Birmingham, Birmingham, Alabama, USA
| |
Collapse
|
6
|
Beitchman JA, Lifshitz J, Harris NG, Thomas TC, Lafrenaye AD, Hånell A, Dixon CE, Povlishock JT, Rowe RK. Spatial Distribution of Neuropathology and Neuroinflammation Elucidate the Biomechanics of Fluid Percussion Injury. Neurotrauma Rep 2021; 2:59-75. [PMID: 34223546 PMCID: PMC8240834 DOI: 10.1089/neur.2020.0046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Diffuse brain injury is better described as multi-focal, where pathology can be found adjacent to seemingly uninjured neural tissue. In experimental diffuse brain injury, pathology and pathophysiology have been reported far more lateral than predicted by the impact site. We hypothesized that local thickening of the rodent skull at the temporal ridges serves to focus the intracranial mechanical forces experienced during brain injury and generate predictable pathology. We demonstrated local thickening of the skull at the temporal ridges using contour analysis on magnetic resonance imaging. After diffuse brain injury induced by midline fluid percussion injury (mFPI), pathological foci along the anterior-posterior length of cortex under the temporal ridges were evident acutely (1, 2, and 7 days) and chronically (28 days) post-injury by deposition of argyophilic reaction product. Area CA3 of the hippocampus and lateral nuclei of the thalamus showed pathological change, suggesting that mechanical forces to or from the temporal ridges shear subcortical regions. A proposed model of mFPI biomechanics suggests that injury force vectors reflect off the skull base and radiate toward the temporal ridge, thereby injuring ventral thalamus, dorsolateral hippocampus, and sensorimotor cortex. Surgically thinning the temporal ridge before injury reduced injury-induced inflammation in the sensorimotor cortex. These data build evidence for temporal ridges of the rodent skull to contribute to the observed pathology, whether by focusing extracranial forces to enter the cranium or intracranial forces to escape the cranium. Pre-clinical investigations can take advantage of the predicted pathology to explore injury mechanisms and treatment efficacy.
Collapse
Affiliation(s)
- Joshua A Beitchman
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Midwestern University, Glendale, Arizona, USA
| | - Jonathan Lifshitz
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Arizona State University, Tempe, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
| | - Neil G Harris
- UCLA Brain Injury Research Center, Department of Neurosurgery, and Intellectual Development and Disabilities Research Center, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, California, USA
| | - Theresa Currier Thomas
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Arizona State University, Tempe, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
| | | | - Anders Hånell
- Virginia Commonwealth University, Richmond, Virginia, USA.,Uppsala University Hospital, Uppsala, Sweden
| | | | | | - Rachel K Rowe
- BARROW Neurological Institute at Phoenix Children's Hospital, Phoenix, Arizona, USA.,Child Health, University of Arizona College of Medicine-Phoenix, Phoenix, Arizona, USA.,Phoenix VA Health Care System, Phoenix, Arizona, USA
| |
Collapse
|
7
|
Ma X, Aravind A, Pfister BJ, Chandra N, Haorah J. Animal Models of Traumatic Brain Injury and Assessment of Injury Severity. Mol Neurobiol 2019; 56:5332-5345. [DOI: 10.1007/s12035-018-1454-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/07/2018] [Indexed: 10/27/2022]
|
8
|
Clausen F, Hansson HA, Raud J, Marklund N. Intranasal Administration of the Antisecretory Peptide AF-16 Reduces Edema and Improves Cognitive Function Following Diffuse Traumatic Brain Injury in the Rat. Front Neurol 2017; 8:39. [PMID: 28261150 PMCID: PMC5306199 DOI: 10.3389/fneur.2017.00039] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/27/2017] [Indexed: 12/19/2022] Open
Abstract
A synthetic peptide with antisecretory activity, antisecretory factor (AF)-16, improves injury-related deficits in water and ion transport and decreases intracranial pressure after experimental cold lesion injury and encephalitis although its role in traumatic brain injury (TBI) is unknown. AF-16 or an inactive reference peptide was administrated intranasally 30 min following midline fluid percussion injury (mFPI; n = 52), a model of diffuse mild-moderate TBI in rats. Sham-injured (n = 14) or naïve (n = 24) animals were used as controls. The rats survived for either 48 h or 15 days post-injury. At 48 h, the animals were tested in the Morris water maze (MWM) for memory function and their brains analyzed for cerebral edema. Here, mFPI-induced brain edema compared to sham or naïve controls that was significantly reduced by AF-16 treatment (p < 0.05) although MWM performance was not altered. In the 15-day survival groups, the MWM learning and memory abilities as well as histological changes were analyzed. AF-16-treated brain-injured animals shortened both MWM latency and swim path in the learning trials (p < 0.05) and improved probe trial performance compared to brain-injured controls treated with the inactive reference peptide. A modest decrease by AF-16 on TBI-induced changes in hippocampal glial acidic fibrillary protein (GFAP) staining (p = 0.11) was observed. AF-16 treatment did not alter any other immunohistochemical analyses (degenerating neurons, beta-amyloid precursor protein (β-APP), and Olig2). In conclusion, intranasal AF-16-attenuated brain edema and enhanced visuospatial learning and memory following diffuse TBI in the rat. Intranasal administration early post-injury of a promising neuroprotective substance offers a novel treatment approach for TBI.
Collapse
Affiliation(s)
- Fredrik Clausen
- Unit for Neurosurgery, Department of Neuroscience, Uppsala University , Uppsala , Sweden
| | - Hans-Arne Hansson
- Institute of Biomedicine, University of Gothenburg , Göteborg , Sweden
| | - Johan Raud
- Lantmännen AS Faktor AB , Stockholm , Sweden
| | - Niklas Marklund
- Unit for Neurosurgery, Department of Neuroscience, Uppsala University , Uppsala , Sweden
| |
Collapse
|