| Objective: Ischemic stroke is serious harmful to human health for its high incidence, high mortality and high morbidity and of which the most common is the focal cerebral ischemia. In the treatments of ischemic stroke, rebuilding the blood supplies of the infarction area, which is also called reperfusion, usually aggravates functional, structural damage and metabolic disorder to tissues and cells, and the problem of reperfusion injury is the pressing clinical problem that we need to deal with. Postconditioning method can be used to reduce ischemic cerebral infarction area, protect the endothelial function, which involve more powerful endogenous protective mechanisms of reperfusion injury in cerebral ischemia, and act positively in prevention and treatment of ischemic hearts, brains and peripheral vascular diseases.Neurogenesis is difficult after the central nervous system (CNS) injury, mainly because the axonal growth inhibitor prevented regeneration of damaged neural fibers. In recent studies, RGMa (repulsive guidance molecule, RGM) which is one kind of axon guidance molecules also can inhibit axonal regeneration. In this study, different postconditioning treatments were taken in focal cerebral ischemia/reperfusion, different methods of to measure the cerebral infarction area impacted by different methods and to detect the expression laws of RGMa, IL-1βand IL-6 in ischemic cortex and hippocampus at different time. Then we can study the treatment of ischemic brain protective effect and influence.Methods: Part I 60 adult Sprague-Dawley (SD) rats, using rat suture The modes of middle cerebral artery ischemia/reperfusion (middle cerebral artery occlusion, MCAO) formed by 60 adult Sprague-Dawley (SD) rats were prepared by the method of thread embolus, divided into 4 groups randomly, and observed after 48h and 1week, contained with blank control group, sham operation group, ischemia/reperfusion group and ischemia postconditioning group after ischemia. The samples of each group were taken 48h and 1week after the reperfusion, the pathological neuronal cells morphology observed by H-E staining, the mRNA expression of RGMa detected by the reverse transcription-polymerase chain reaction (RT-PCR) and the status of axon growth of the same area at the same time.Part II: 105 adult SD rats were divided into 7 groups randomly, which included blank control group, sham operation group, ischemia/reperfusion group, ischemia postconditioning (10s and 5min cycle) group, separated by ischemia post-treatment group and delayed ischemic postconditioning group. The specimens were taken 48h after the reperfusion. The areas of cerebral infarction were measured by TTC dyeing Method, The expression of the RGMa and local inflammatory response (IL-1β, IL-6) in the ischemic cortex and hippocampus were detected by immunohistochemistry method. The mRNA expression of the RGMa of ischemic cortex and hippocampus was detected by the reverse transcription - polymerase chain reaction (RT-PCR).Results: Part I The expression of the RGMa mRNA and protein in the ischemic cortex and the hippocampus of the focal cerebral ischemia / reperfusion had increased, and Compared with ischemia / reperfusion group, the expression of RGMa protein and mRNA in the ischemic cortex and the hippocampus of the ischemic postconditioning group had significantly low down (P<0.01), reduced symptoms of neurological impairment significantly (P<0.05). The axonal regeneration of the postconditioning group had been improved after the axonal injured (P<0.01).Part II: Compared with the ischemia/reperfusion groups, the ischemic area in the ipsilateral cortex and hippocampus of the ischemic postconditioning group of 10s was least, expression of RGMa had significantly low down (P <0.01), the local inflammatory response also had been reduced. The ischemic area in the ipsilateral cortex and hippocampus the ischemic postconditioning group of 5 min and delayed postconditioning group had been reduced (P<0.05), expression of RGMa had low down and the local inflammatory response had been lessened (P<0.05). But the remote postconditioning group had not significant change compared with the model group (P>0.05).Conclusion: The expression of RGMa in the ischemic cortex and hippocampus of focal cerebral ischemia/reperfusion injured model of rats had increased; the motor dysfunction of the postconditioning group had been improved, the RGMa, IL-1βand IL-6 in the ischemic cortex and hippocampus had lower expression, the axonal regeneration had also been improved. In addition, the implementation of early and proximal cerebral ischemic postconditioning was the best protective by far. |
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