Translational Research for axona regeneration by using Stroke model of minature pig

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Background and Purpose The first purpose of the present set of studies was to introduce a reproducible stroke model in the gyrencephalic brain of miniature pig with minimum invasiveness. The paper provides information on both the surgical technique and the methods of quantification of ischemic damage to both grey and white matter in the miniature pig. The second purpose was to apply this new stroke model for the translational research for the neuronal regeneration by using thestem cell trasplantation into the ischemic brain. Methods Sixteen male miniature pigs were randomly divided into three groups and underwent transcranial surgery, a frontotemporal approach with orbital rim osteotomy, for : permanent middle cerebral artery occlusion (MCAO) (n=5), permanent internal carotid artery occlusion (ICAO) (n=6) and sham operation (n=5). Histological mapping and magnetic resonance (MR) imaging were used to delineate the areas of ischemia. Subventricular zone (SVZ) cells isolated from the mini … More ature pig were cultured in Iscove's modified Dulbecco's medium in the presence of basic fibroblast growth factor for 8 days. We stereotaxically transplanted subventricular zone (SVZ) cells labeled by ferromagnetic particles into stroked miniature pig. The transplanted cells were non-invasively tracked using magnetic resonance imaging (MRI). To detect ferromagnetic-labeled SVZ cells in the host brain, we stained sagittal or coronal sections for iron using Prussian blue reaction. Results The volumes of the infarction measured directly from MR images were 16.2 ±1.1, 1.5±0.5 and 0.0±0.0 cm^3 (mean±SD) in the MCAO, ICAO and sham-operation groups, respectively. The histological and MR imaging volumes showed a good correlation (r^2=0.86, p <0.0001) although the infarct volume measured by quantitative histopathology was smaller than that measured by MRI. Immunohistochemical staining using amyloid precursor protein antibody (APP) allowed us to evaluate the axonal damage, providing total APP score of 43.8±3.5 (mean±SD) in the MCAO. MRI signals detected the tranplanted cells with labeling at the lesion, and these signals were detected 1 and 2 weeks after transplantation. Prussian blue-positive cells were also detected in the same lesion where the cells were transplanted. The transplanted cells were likely to be just homing in the host brain. We have neither confirmed the construction of the network between the transplanted cells and host brain. Conclusions This paper describes a simple and reproducible method for the induction of white and grey matter damage in focal cerebral ischemia with minimum invasiveness. This miniature pig stroke model has utility for studying the pathophysiology of ischemia in gyrencephalic brain and for the assessing the therapeutic efficacy of drugs or stem cell transplants, prior to initiating human clinical trials. Less