| Objective:1.The purpose of this set of studies is to design a stable, reproduciblecerebral ischemia model in the gyrencephalic brain of large animals，Evaluation ofthe model by magnetic resonance diffusion-weighted imaging (DWI) and magneticresonance imaging(MRI);2.To study the anatomy characteristics of the minipigbrain blood vessels, comparing with the differences in cerebrovascular betweenswine and human;3.Observed the miniature pigs recovery of limb functionthrough early rehabilitation, to explore pigs can be used as the ideal animal modelof cerebral ischemia and rehabilitation after stroke research.Methods: Use a Alabama minipig product Cerebral vascular cast specimens.Nineteen miniature pigs were randomly divided into two groups and underwenttranscranial surgery involving a frontotemporal approach with orbital rimosteotomy for permanent middle cerebral artery occlusion (MCAO;12animals)and a sham operation(7animals). The MCAO was induced by electrocoagulationof the two MCAs from the proximal and the distal. The MCAs were thentransected at the proximal and distal sites to ensure completeness of occlusion.Sham-operated animals underwent surgery in the same way as animals in theMCAO group, except without the electrocoagulation and blood vessel transectionsteps.The MCAO group was divided into2groups (rehabilitation group6, the control group6).Behavior changes and neurological deficit score were performedafter3h,6h,12h,1day to7days of all animals.48hours after surgery, therehabilitation group by early functional training, while the control group did notconduct physical training, observation rehabilitation group and control groupanimals recovery of limb function, assessing the effect of functional training oncerebral infarction in pig.Hematoxylin-eosin staining and issl staining to observedmorphological changes of infarct zone and Nissl bodies after7days.Results:1.The success rate of the sham-operated group is100%, While the MCAOgroup model success rate is83.3%.2.The cerebral blood vessels exist somedifferences between pigs and human, The pig has special anatomical features of itsinternal carotid artery system,the ascending pharyngeal artery forms rete mirabilebefore into the skull. Then the internal carotid artery turn into the posteriorcommunicating artery, the anterior choroidal artery, anterior cerebral artery andmiddle cerebral artery after into the cranium. Usually, two MCAs originate fromthe ICA in each hemisphere in pigs, one coursing laterally and another rostrallyover the olfactory tract, Location is not exactly the same as the bilateral middlecerebral artery. In contrast, one MCA (the so-called M1segment) originates fromthe ICA, courses laterally, and results in two branches (M2segments) in humans.3.MCAO group with varying degrees of focal neurological dysfunction(hemiplegia based), sham operation group limb dysfunction. The neurologicaldeficit scores of MCAO group reached maximum values as early as6hours afterischemia, and then gradually reduce. Sham operation group, the total score and motor scores were significantly lower than the MCAO group, MCAO group andsham-operation group neurological deficit score difference was statisticallysignificant (P <0.000).4.MRI showed abnormal signal in the caudate nucleus andthe cerebral cortex in the MCAO group; and no abnormal behavior was observedin the sham-operated group.The volumes of infarction measured directly fromDWI were3.99+-1.5cm~3and0.0+-0.0cm~3(mean+-standard deviation [SD], p<0.001) in the MCAO, and sham-operated groups, respectively.5.H-E staining confirmed that irreversible ischemic area inthe MCAO group, The result of Nissl staining is brain tissue necrosis.6.Recoveryof limb function of the rehabilitation group and the control group have nosignificant differences.Conclusion:1.The miniature pig model of focal cerebral ischemia has goodrepeatability,stability and easy to operate. Evaluate the cerebral ischemia modelin the experimental throught DWI and MRI,The results show that the shape, extentconsistent with ischemic performance, It is means that the experimental method offocal cerebral ischemia animal model is feasible.2.The cerebral blood vessels existsome differences between pigs and human.3.Middle cerebral artery occlusion toresult in ischemic brain injury can cause the miniture pig obvious signs ofneurological deficit (such as limb paralysis), But the two groups recovery of limbfunction and no difference, and the time of recovery is very rapidly, that the pigexperimental model is not suitable for late stroke rehabilitation, and is not suitablefor an ideal animal model for the study as a post-stroke rehabilitation neural mechanisms. |
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