Photochemically induced cerebral ischemia in a mouse model

Department of Neurosurgery, Chonnam National University Hospital, Gwangju 501-757, South Korea. <>
Surgical Neurology (Impact Factor: 1.67). 07/2007; 67(6):620-5; discussion 625. DOI: 10.1016/j.surneu.2006.08.077
Source: PubMed


MCAO has been widely used to produce ischemic brain lesions. The lesions induced by MCAO tend to be variable in size because of the variance in the collateral blood supply found in the mouse brain.
We modified the rat photothrombosis model for use in mice. Male C57BL/6 mice were subjected to focal cerebral ischemia by photothrombosis of cortical microvessels. Cerebral infarction was produced by intraperitoneal injection of rose bengal, a photosensitive dye, and by focal illumination through the skull. Motor impairment was assessed by the accelerating rotarod and staircase tests. The brain was perfusion fixed for histologic determination of infarct volume 4 weeks after stroke.
The lesion was located in the frontal and parietal cortex and the underlying white matter was partly affected. A relatively constant infarct volume was achieved 1 month after photothrombosis. The presence of the photothrombotic lesion significantly impaired the motor performance as measured by the rotarod and staircase tests. Our findings show that photothrombotic infarction in mice is highly reproducible in size and location.
This procedure can provide a simple model of cerebral infarction for a unilateral motor cortex lesion. In addition, it can provide a suitable model for the study of potential neuroprotective and therapeutic agents in human stroke.

    • "Thus, MCA transection induces larger infarct volume in GFAP 2/2 Vim 2/2 mice than in WT mice (Li et al., 2008), which may lead to incomparable functional outcome during the recovery phase after stroke. The photosensitive dye (Rose Bengal) becomes activated and induces endothelial damage with platelet activation and thrombosis, when illuminated by a cold light source, resulting in local blood flow interruption by a rapidly evolving ischemic damage without salvageable penumbra (Lee et al., 2007; Watson et al., 1985). Therefore, to avoid the variation in lesion volume on behavioral recovery after stroke, we performed a unilateral photothrombosis to the forelimb motor area to generate a consistent focal cortical ischemia of "
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    ABSTRACT: The functional role of reactive astrocytes after stroke is controversial. To elucidate whether reactive astrocytes contribute to neurological recovery, we compared behavioral outcome, axonal remodeling of the corticospinal tract (CST), and the spatio-temporal change of chondroitin sulfate proteoglycan (CSPG) expression between wild-type (WT) and glial fibrillary acidic protein/vimentin double knockout (GFAP–/–Vim–/–) mice subjected to Rose Bengal induced cerebral cortical photothrombotic stroke in the right forelimb motor area. A foot-fault test and a single pellet reaching test were performed prior to and on day 3 after stroke, and weekly thereafter to monitor functional deficit and recovery. Biotinylated dextran amine (BDA) was injected into the left motor cortex to anterogradely label the CST axons. Compared with WT mice, the motor functional recovery and BDA-positive CST axonal length in the denervated side of the cervical gray matter were significantly reduced in GFAP–/–Vim–/– mice (n = 10/group, P < 0.01). Immunohistological data showed that in GFAP–/–Vim–/– mice, in which astrocytic reactivity is attenuated, CSPG expression was significantly increased in the lesion remote areas in both hemispheres, but decreased in the ischemic lesion boundary zone, compared with WT mice (n = 12/group, P < 0.001). Our data suggest that attenuated astrocytic reactivity impairs or delays neurological recovery by reducing CST axonal remodeling in the denervated spinal cord. Thus, manipulation of astrocytic reactivity post stroke may represent a therapeutic target for neurorestorative strategies. GLIA 2014
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    • "Blood flow is reduced or even blocked after that and ischemia insult occurs. Photothrombosis, which is highly reproducible with respect to the infarct location and size, will be an optimal focal ischemia model to study behavioral alterations with high spatial resolution (Kuroiwa et al., 2009; Lee et al., 2007; Nowicka et al., 2008). Moreover, consecutive rotarod tests can accelerate recovery after photothrombosis and offer advantages to investigate a full pathologic process of ischemia (Watson et al., 1985; Dirnagl, 2010; Wang et al., 2013). "
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    ABSTRACT: Background Neurobehavioral assessments have been considered as an essential component of preclinical research in ischemic stroke. However, real-time neurobehavioral evaluation is seldom applied during ischemia induction as it is usually accompanied with anesthesia. New method We induced photothrombosis in freely moving mice after one-week recovery from cannula implantation surgeries. After rose bengal (RB) injection (100 mg/kg, i.p.), photothrombosis was induced in freely moving mice by 473 nm laser irradiation through the cannulas implanted into unilateral primary motor cortex beforehand. Mice received nimodipine (15 mg/kg, i.p.), a widely used anti-ischemic agent, or vehicle before irradiation. Motor coordination and equilibrium were evaluated by rotarod and rung walk tests throughout the whole process of ischemia. Endurance capacity was assessed by treadmill at 1 day and 7 days after irradiation. Mice were decapitated at different time points post irradiation for TTC (2,3,5-triphenyltetrazolium chloride) staining. Results Consistent with the results of TTC staining, motor deficits firstly occurred at 15-min post irradiation and aggravated 1-day later, while the capacity improved 3-days later and partially recovered 7-days post irradiation. And, the recovery process was accelerated by nimodipine application. Comparison with existing methods This method established a precise linkage between focal brain ischemia development and neurobehavioral deficits throughout a full scale of photothrombosis, which avoided the confounding factors of anesthetics and surgeries on neurobehavioral assessments, as infarct was induced in freely moving mice. Conclusions This method with high temporal and spatial resolution will be an optimal model for neurobehavioral evaluation in preclinical anti-ischemic drug screening.
    Full-text · Article · Oct 2014 · Journal of Neuroscience Methods
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    • "Light-activated Rose Bengal induces free-radical injury to endothelial cells, aggregation of platelets and finally occlusion of the injured vessel. Advantages of the Rose Bengal photothrombotic model included the non-invasiveness of the operation and resulting lesions of reproducible size with well-defined boundaries between the infarct and normal tissues11,35,64). Unlike the MCAO model, which showed a diffuse stem cell distribution by IA infusion and a localized pattern by IV infusion38), the photothrombotic infarction model showed similar patterns of stem cell distribution following IA and IV infusions, in the peripheral zone of the infarction. "
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    ABSTRACT: This study aimed to evaluate the hypotheses that administration routes [intra-arterial (IA) vs. intravenous (IV)] affect the early stage migration of transplanted human bone marrow-derived mesenchymal stem cells (hBM-MSCs) in acute brain infarction. Male Sprague-Dawley rats (n=40) were subjected to photothrombotic infarction. Three days after photothrombotic infarction, rats were randomly allocated to one of four experimental groups [IA group : n=12, IV group : n=12, superparamagnetic iron oxide (SPIO) group : n=8, control group : n=8]. All groups were subdivided into 1, 6, 24, and 48 hours groups according to time point of sacrifice. Magnetic resonance imaging (MRI) consisting of T2 weighted image (T2WI), T2(*) weighted image (T2(*)WI), susceptibility weighted image (SWI), and diffusion weighted image of rat brain were obtained prior to and at 1, 6, 24, and 48 hours post-implantation. After final MRI, rats were sacrificed and grafted cells were analyzed in brain and lung specimen using Prussian blue and immunohistochemical staining. Grafted cells appeared as dark signal intensity regions at the peri-lesional zone. In IA group, dark signals in peri-lesional zone were more prominent compared with IV group. SWI showed largest dark signal followed by T2(*)WI and T2WI in both IA and IV groups. On Prussian blue staining, IA administration showed substantially increased migration and a large number of transplanted hBM-MSCs in the target brain than IV administration. The Prussian blue-positive cells were not detected in SPIO and control groups. In a rat photothrombotic model of ischemic stroke, selective IA administration of human mesenchymal stem cells is more effective than IV administration. MRI and histological analyses revealed the time course of cell migration, and the numbers and distribution of hBM-MSCs delivered into the brain.
    Full-text · Article · Dec 2013 · Journal of Korean Neurosurgical Society
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