1
|
Abstract
Traumatic brain injury (TBI) is a heterogeneous brain injury which represents one of the leading causes of mortality and disability worldwide. Rodent TBI models are helpful to examine the cellular and molecular mechanisms after injury. Controlled cortical impact (CCI) is one of the most commonly used TBI models in rats and mice, based on its consistency of injury and ease of implementation. Here, we describe a CCI protocol to induce a moderate contusion to the somatosensory motor cortex. We provide additional protocols for monitoring animals after CCI induction.
Collapse
Affiliation(s)
| | - Tifenn Clément
- CNRS UMR5287, INCIA, University of Bordeaux, Bordeaux, France
| | | | - Nikolaus Plesnila
- Institute for Stroke and Dementia Research (ISD), University of Munich Medical Center, Munich, Germany
| | - André Obenaus
- Department of Pediatrics, University of California, Irvine, Irvine, CA, USA
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA
| | - Jérôme Badaut
- CNRS UMR5287, INCIA, University of Bordeaux, Bordeaux, France.
- Department of Basic Sciences, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| |
Collapse
|
2
|
Ichkova A, Rodriguez-Grande B, Zub E, Saudi A, Fournier ML, Aussudre J, Sicard P, Obenaus A, Marchi N, Badaut J. Early cerebrovascular and long-term neurological modifications ensue following juvenile mild traumatic brain injury in male mice. Neurobiol Dis 2020. [PMID: 32442681 DOI: 10.1016/j.nbd.2020.1049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
Clinical evidence suggests that a mild traumatic brain injury occurring at a juvenile age (jmTBI) may be sufficient to elicit pathophysiological modifications. However, clinical reports are not adequately integrated with experimental studies examining brain changes occurring post-jmTBI. We monitored the cerebrovascular modifications and assessed the long-term behavioral and electrographic changes resulting from experimental jmTBI. In vivo photoacoustic imaging demonstrated a decrease of cerebrovascular oxygen saturation levels in the impacted area hours post-jmTBI. Three days post-jmTBI oxygenation returned to pre-jmTBI levels, stabilizing at 7 and 30 days after the injury. At the functional level, cortical arterioles displayed no NMDA vasodilation response, while vasoconstriction induced by thromboxane receptor agonist was enhanced at 1 day post-jmTBI. Arterioles showed abnormal NMDA vasodilation at 3 days post-jmTBI, returning to normality at 7 days post injury. Histology showed changes in vessel diameters from 1 to 30 days post-jmTBI. Neurological evaluation indicated signs of anxiety-like behavior up to 30 days post-jmTBI. EEG recordings performed at the cortical site of impact 30 days post-jmTBI did not indicate seizures activity, although it revealed a reduction of gamma waves as compared to age matched sham. Histology showed decrease of neuronal filament staining. In conclusion, experimental jmTBI triggers an early cerebrovascular hypo‑oxygenation in vivo and faulty vascular reactivity. The exact topographical coherence and the direct casualty between early cerebrovascular changes and the observed long-term neurological modifications remain to be investigated. A potential translational value for cerebro-vascular oxygen monitoring in jmTBI is discussed.
Collapse
Affiliation(s)
| | | | - Emma Zub
- Cerebrovascular and Glia Research Laboratory, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France
| | - Amel Saudi
- Cerebrovascular and Glia Research Laboratory, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France
| | | | | | - Pierre Sicard
- INSERM, CNRS, Université de Montpellier, PhyMedExp, IPAM, Montpellier, France
| | - André Obenaus
- CNRS UMR5287, University of Bordeaux, Bordeaux, France; Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, USA; Basic Science Department, Loma Linda University School of Medicine, Loma Linda, CA, USA; Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, UC Riverside, Riverside, CA, USA; Department of Pediatrics, University of California, Irvine, Irvine, CA, USA
| | - Nicola Marchi
- Cerebrovascular and Glia Research Laboratory, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France.
| | - Jerome Badaut
- CNRS UMR5287, University of Bordeaux, Bordeaux, France; Basic Science Department, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| |
Collapse
|
3
|
Ichkova A, Rodriguez-Grande B, Zub E, Saudi A, Fournier ML, Aussudre J, Sicard P, Obenaus A, Marchi N, Badaut J. Early cerebrovascular and long-term neurological modifications ensue following juvenile mild traumatic brain injury in male mice. Neurobiol Dis 2020; 141:104952. [PMID: 32442681 DOI: 10.1016/j.nbd.2020.104952] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/05/2020] [Accepted: 05/17/2020] [Indexed: 12/15/2022] Open
Abstract
Clinical evidence suggests that a mild traumatic brain injury occurring at a juvenile age (jmTBI) may be sufficient to elicit pathophysiological modifications. However, clinical reports are not adequately integrated with experimental studies examining brain changes occurring post-jmTBI. We monitored the cerebrovascular modifications and assessed the long-term behavioral and electrographic changes resulting from experimental jmTBI. In vivo photoacoustic imaging demonstrated a decrease of cerebrovascular oxygen saturation levels in the impacted area hours post-jmTBI. Three days post-jmTBI oxygenation returned to pre-jmTBI levels, stabilizing at 7 and 30 days after the injury. At the functional level, cortical arterioles displayed no NMDA vasodilation response, while vasoconstriction induced by thromboxane receptor agonist was enhanced at 1 day post-jmTBI. Arterioles showed abnormal NMDA vasodilation at 3 days post-jmTBI, returning to normality at 7 days post injury. Histology showed changes in vessel diameters from 1 to 30 days post-jmTBI. Neurological evaluation indicated signs of anxiety-like behavior up to 30 days post-jmTBI. EEG recordings performed at the cortical site of impact 30 days post-jmTBI did not indicate seizures activity, although it revealed a reduction of gamma waves as compared to age matched sham. Histology showed decrease of neuronal filament staining. In conclusion, experimental jmTBI triggers an early cerebrovascular hypo‑oxygenation in vivo and faulty vascular reactivity. The exact topographical coherence and the direct casualty between early cerebrovascular changes and the observed long-term neurological modifications remain to be investigated. A potential translational value for cerebro-vascular oxygen monitoring in jmTBI is discussed.
Collapse
Affiliation(s)
| | | | - Emma Zub
- Cerebrovascular and Glia Research Laboratory, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France
| | - Amel Saudi
- Cerebrovascular and Glia Research Laboratory, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France
| | | | | | - Pierre Sicard
- INSERM, CNRS, Université de Montpellier, PhyMedExp, IPAM, Montpellier, France
| | - André Obenaus
- CNRS UMR5287, University of Bordeaux, Bordeaux, France; Department of Pediatrics, Loma Linda University School of Medicine, Loma Linda, CA, USA; Basic Science Department, Loma Linda University School of Medicine, Loma Linda, CA, USA; Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, UC Riverside, Riverside, CA, USA; Department of Pediatrics, University of California, Irvine, Irvine, CA, USA
| | - Nicola Marchi
- Cerebrovascular and Glia Research Laboratory, Department of Neuroscience, Institute of Functional Genomics (UMR 5203 CNRS-U1191 INSERM, University of Montpellier), Montpellier, France.
| | - Jerome Badaut
- CNRS UMR5287, University of Bordeaux, Bordeaux, France; Basic Science Department, Loma Linda University School of Medicine, Loma Linda, CA, USA.
| |
Collapse
|
4
|
Clément T, Lee JB, Ichkova A, Rodriguez-Grande B, Fournier ML, Aussudre J, Ogier M, Haddad E, Canini F, Koehl M, Abrous DN, Obenaus A, Badaut J. Juvenile mild traumatic brain injury elicits distinct spatiotemporal astrocyte responses. Glia 2019; 68:528-542. [PMID: 31670865 DOI: 10.1002/glia.23736] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022]
Abstract
Mild-traumatic brain injury (mTBI) represents ~80% of all emergency room visits and increases the probability of developing long-term cognitive disorders in children. To date, molecular and cellular mechanisms underlying post-mTBI cognitive dysfunction are unknown. Astrogliosis has been shown to significantly alter astrocytes' properties following brain injury, potentially leading to significant brain dysfunction. However, such alterations have never been investigated in the context of juvenile mTBI (jmTBI). A closed-head injury model was used to study jmTBI on postnatal-day 17 mice. Astrogliosis was evaluated using glial fibrillary acidic protein (GFAP), vimentin, and nestin immunolabeling in somatosensory cortex (SSC), dentate gyrus (DG), amygdala (AMY), and infralimbic area (ILA) of prefrontal cortex in both hemispheres from 1 to 30 days postinjury (dpi). In vivo T2-weighted-imaging (T2WI) and diffusion tensor imaging (DTI) were performed at 7 and 30 dpi to examine tissue level structural alterations. Increased GFAP-labeling was observed up to 30 dpi in the ipsilateral SSC, the initial site of the impact. However, vimentin and nestin expression was not perturbed by jmTBI. The morphology of GFAP positive cells was significantly altered in the SSC, DG, AMY, and ILA up to 7 dpi that some correlated with magnetic resonance imaging changes. T2WI and DTI values were significantly altered at 30 dpi within these brain regions most prominently in regions distant from the impact site. Our data show that jmTBI triggers changes in astrocytic phenotype with a distinct spatiotemporal pattern. We speculate that the presence and time course of astrogliosis may contribute to pathophysiological processes and long-term structural alterations following jmTBI.
Collapse
Affiliation(s)
| | - Jeong B Lee
- Department of Physiology, Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| | | | | | | | | | - Michael Ogier
- Département des Neurosciences et Sciences Cognitives, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Elizabeth Haddad
- Department of Pediatrics, University of California, Irvine, Irvine, California
| | - Frederic Canini
- Département des Neurosciences et Sciences Cognitives, Institut de Recherche Biomédicale des Armées, Brétigny-sur-Orge, France
| | - Muriel Koehl
- Neurocentre Magendie INSERM U1215, Bordeaux, France
| | | | - Andre Obenaus
- Department of Physiology, Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California.,Department of Pediatrics, University of California, Irvine, Irvine, California
| | - Jerome Badaut
- CNRS UMR5287, University of Bordeaux, Bordeaux, France.,Department of Physiology, Basic Sciences, Loma Linda University School of Medicine, Loma Linda, California
| |
Collapse
|
5
|
Boiziau C, Nikolski M, Mordelet E, Aussudre J, Vargas-Sanchez K, Petry KG. A Peptide Targeting Inflammatory CNS Lesions in the EAE Rat Model of Multiple Sclerosis. Inflammation 2018. [PMID: 29516383 DOI: 10.1007/s10753-018-0748-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Multiple sclerosis is characterized by inflammatory lesions dispersed throughout the central nervous system (CNS) leading to severe neurological handicap. Demyelination, axonal damage, and blood brain barrier alterations are hallmarks of this pathology, whose precise processes are not fully understood. In the experimental autoimmune encephalomyelitis (EAE) rat model that mimics many features of human multiple sclerosis, the phage display strategy was applied to select peptide ligands targeting inflammatory sites in CNS. Due to the large diversity of sequences after phage display selection, a bioinformatics procedure called "PepTeam" designed to identify peptides mimicking naturally occurring proteins was used, with the goal to predict peptides that were not background noise. We identified a circular peptide CLSTASNSC called "Ph48" as an efficient binder of inflammatory regions of EAE CNS sections including small inflammatory lesions of both white and gray matter. Tested on human brain endothelial cells hCMEC/D3, Ph48 was able to bind efficiently when these cells were activated with IL1β to mimic inflammatory conditions. The peptide is therefore a candidate for further analyses of the molecular alterations in inflammatory lesions.
Collapse
Affiliation(s)
- Claudine Boiziau
- INSERM, UMR 1049, F-33076, Bordeaux, France. .,Univ. Bordeaux, Neuroinflammation Imaging and Therapy of Multiple Sclerosis, F-33076, Bordeaux, France. .,INSERM, UMR 1026, BioTis, F-33 076, Bordeaux, France.
| | - Macha Nikolski
- Univ. Bordeaux, CBiB, F-33076, Bordeaux, France.,CNRS, LaBRI UMR 5800, F-33400, Talence, France
| | - Elodie Mordelet
- INSERM, UMR 1049, F-33076, Bordeaux, France.,Univ. Bordeaux, Neuroinflammation Imaging and Therapy of Multiple Sclerosis, F-33076, Bordeaux, France
| | - Justine Aussudre
- INSERM, UMR 1049, F-33076, Bordeaux, France.,Univ. Bordeaux, Neuroinflammation Imaging and Therapy of Multiple Sclerosis, F-33076, Bordeaux, France
| | - Karina Vargas-Sanchez
- INSERM, UMR 1049, F-33076, Bordeaux, France.,Univ. Bordeaux, Neuroinflammation Imaging and Therapy of Multiple Sclerosis, F-33076, Bordeaux, France.,Biomedical Sciences Research Group, GRINCIBIO, School of Medicine, Universidad Antonio Nariño, Bogotà, Colombia
| | - Klaus G Petry
- INSERM, UMR 1049, F-33076, Bordeaux, France.,Univ. Bordeaux, Neuroinflammation Imaging and Therapy of Multiple Sclerosis, F-33076, Bordeaux, France.,INSERM, UMR1029, F-33076, Bordeaux, France
| |
Collapse
|
6
|
Rodriguez-Grande B, Obenaus A, Ichkova A, Aussudre J, Bessy T, Barse E, Hiba B, Catheline G, Barrière G, Badaut J. Gliovascular changes precede white matter damage and long-term disorders in juvenile mild closed head injury. Glia 2018; 66:1663-1677. [DOI: 10.1002/glia.23336] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 03/09/2018] [Accepted: 03/16/2018] [Indexed: 12/21/2022]
Affiliation(s)
- Beatriz Rodriguez-Grande
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
| | - Andre Obenaus
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
- Department of Pediatrics; Loma Linda University School of Medicine; Loma Linda California
- Basic Science Department; Loma Linda University School of Medicine; Loma Linda California
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences; UC Riverside; Riverside California
- Department of Pediatrics; University of California, Irvine; Irvine California
| | - Aleksandra Ichkova
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
| | - Justine Aussudre
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
| | - Thomas Bessy
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
| | - Elodie Barse
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
- EPHE, PSL; Bordeaux France
| | - Bassem Hiba
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
| | - Gwénaëlle Catheline
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
- EPHE, PSL; Bordeaux France
| | - Grégory Barrière
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
| | - Jerome Badaut
- CNRS UMR5287, Institut de Neurosciences Cognitives et Intégratives d'Aquitaine, University of Bordeaux; Bordeaux France
- Basic Science Department; Loma Linda University School of Medicine; Loma Linda California
| |
Collapse
|
7
|
Jullienne A, Fukuda AM, Ichkova A, Nishiyama N, Aussudre J, Obenaus A, Badaut J. Modulating the water channel AQP4 alters miRNA expression, astrocyte connectivity and water diffusion in the rodent brain. Sci Rep 2018. [PMID: 29520011 PMCID: PMC5843607 DOI: 10.1038/s41598-018-22268-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Aquaporins (AQPs) facilitate water diffusion through the plasma membrane. Brain aquaporin-4 (AQP4) is present in astrocytes and has critical roles in normal and disease physiology. We previously showed that a 24.9% decrease in AQP4 expression after in vivo silencing resulted in a 45.8% decrease in tissue water mobility as interpreted from magnetic resonance imaging apparent diffusion coefficients (ADC). Similar to previous in vitro studies we show decreased expression of the gap junction protein connexin 43 (Cx43) in vivo after intracortical injection of siAQP4 in the rat. Moreover, siAQP4 induced a loss of dye-coupling between astrocytes in vitro, further demonstrating its effect on gap junctions. In contrast, silencing of Cx43 did not alter the level of AQP4 or water mobility (ADC) in the brain. We hypothesized that siAQP4 has off-target effects on Cx43 expression via modification of miRNA expression. The decreased expression of Cx43 in siAQP4-treated animals was associated with up-regulation of miR224, which is known to target AQP4 and Cx43 expression. This could be one potential molecular mechanism responsible for the effect of siAQP4 on Cx43 expression, and the resultant decrease in astrocyte connectivity and dramatic effects on ADC values and water mobility.
Collapse
Affiliation(s)
- Amandine Jullienne
- Basic Sciences Department, Loma Linda University, Loma Linda, CA, 92354, USA.,Department of Physiology, Loma Linda University, Loma Linda, CA, 92354, USA
| | - Andrew M Fukuda
- Basic Sciences Department, Loma Linda University, Loma Linda, CA, 92354, USA.,Department of Physiology, Loma Linda University, Loma Linda, CA, 92354, USA
| | | | - Nina Nishiyama
- Department of Physiology, Loma Linda University, Loma Linda, CA, 92354, USA
| | | | - André Obenaus
- Basic Sciences Department, Loma Linda University, Loma Linda, CA, 92354, USA.,Department of Pediatrics, University of California Irvine, Irvine, CA, 92697, USA
| | - Jérôme Badaut
- Basic Sciences Department, Loma Linda University, Loma Linda, CA, 92354, USA. .,Department of Physiology, Loma Linda University, Loma Linda, CA, 92354, USA. .,CNRS-UMR 5287, University of Bordeaux, 33076, Bordeaux, France.
| |
Collapse
|
8
|
Tourdias T, Mori N, Dragonu I, Cassagno N, Boiziau C, Aussudre J, Brochet B, Moonen C, Petry KG, Dousset V. Differential aquaporin 4 expression during edema build-up and resolution phases of brain inflammation. J Neuroinflammation 2011; 8:143. [PMID: 22011386 PMCID: PMC3220647 DOI: 10.1186/1742-2094-8-143] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 10/19/2011] [Indexed: 11/10/2022] Open
Abstract
Background Vasogenic edema dynamically accumulates in many brain disorders associated with brain inflammation, with the critical step of edema exacerbation feared in patient care. Water entrance through blood-brain barrier (BBB) opening is thought to have a role in edema formation. Nevertheless, the mechanisms of edema resolution remain poorly understood. Because the water channel aquaporin 4 (AQP4) provides an important route for vasogenic edema resolution, we studied the time course of AQP4 expression to better understand its potential effect in countering the exacerbation of vasogenic edema. Methods Focal inflammation was induced in the rat brain by a lysolecithin injection and was evaluated at 1, 3, 7, 14 and 20 days using a combination of in vivo MRI with apparent diffusion coefficient (ADC) measurements used as a marker of water content, and molecular and histological approaches for the quantification of AQP4 expression. Markers of active inflammation (macrophages, BBB permeability, and interleukin-1β) and markers of scarring (gliosis) were also quantified. Results This animal model of brain inflammation demonstrated two phases of edema development: an initial edema build-up phase during active inflammation that peaked after 3 days (ADC increase) was followed by an edema resolution phase that lasted from 7 to 20 days post injection (ADC decrease) and was accompanied by glial scar formation. A moderate upregulation in AQP4 was observed during the build-up phase, but a much stronger transcriptional and translational level of AQP4 expression was observed during the secondary edema resolution phase. Conclusions We conclude that a time lag in AQP4 expression occurs such that the more significant upregulation was achieved only after a delay period. This change in AQP4 expression appears to act as an important determinant in the exacerbation of edema, considering that AQP4 expression is insufficient to counter the water influx during the build-up phase, while the second more pronounced but delayed upregulation is involved in the resolution phase. A better pathophysiological understanding of edema exacerbation, which is observed in many clinical situations, is crucial in pursuing new therapeutic strategies.
Collapse
Affiliation(s)
- Thomas Tourdias
- INSERM U,1049 Neuroinflammation, Imagerie et Thérapie de la Sclérose en Plaques, F-33076 Bordeaux, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Tourdias T, Hiba B, Raffard G, Biran M, Nishiguchi T, Aussudre J, Franconi JM, Brochet B, Petry KG, Dousset V. Adapted focal experimental autoimmune encephalomyelitis to allow MRI exploration of multiple sclerosis features. Exp Neurol 2011; 230:248-57. [PMID: 21575634 DOI: 10.1016/j.expneurol.2011.04.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/15/2011] [Accepted: 04/28/2011] [Indexed: 10/18/2022]
Abstract
We aimed to determine an optimal protocol for inducing a focal inflammatory lesion within the rat brain that could be large enough for an easier MRI monitoring while still relevant as a multiple sclerosis (MS) like lesion. We adapted a two-hit model based on pre-sensitization of the Lewis rat with myelin oligodendrocyte protein (MOG) followed by stereotaxic injection of pro-inflammatory cytokines (TNFα+IFNγ) within the internal capsule. We compared the following two strategies to increase focal lesion development for an easier MR translation: (1) a higher sensitization step (MOG50) or (2) a higher cytokine step with lower sensitization (MOG25). Control animals were administered only cytokines without MOG pre-sensitization. Animals were followed with T2, diffusion and T1 post gadolinium weighted images at 1, 3 and 7days following cytokine injection. Immunostaining was performed at the same time points for macrophages (ED1), myelin (MBP and Luxol Fast Blue) and blood brain barrier integrity (IgG). At day 1, the focal lesions depicted with T2-weighted images were very similar among groups and related to vasogenic edema (high apparent diffusion coefficient (ADC), gadolinium enhancement and IgG extravasation) induced by cytokines irrespective of the pre-sensitization step. Then, at day 3, MOG50 rats developed statistically larger T2 lesions than MOG25 and control rats that were correlated with inflammatory cell accumulation. At day 7, MOG50 rats also showed larger T2 lesions than MOG25 and control rats, together with loss of anisotropy that were correlated with demyelination. In contrast, MOG25 and control rats developed similar MR lesions decreasing over time and almost undetectable at day 7. We conclude that with a high pre-sensitization step, the focal lesion can be monitored by MRI whose signal reflects some features of a MS-like lesion, i.e. edema, inflammatory cell accumulation and later demyelination.
Collapse
Affiliation(s)
- Thomas Tourdias
- INSERM U.1049 Neuroinflammation, imagerie et thérapie de sclérose en plaques, F-33076 Bordeaux, France.
| | | | | | | | | | | | | | | | | | | |
Collapse
|