| Objectives: Stroke is a common disease with a high rate of disability. Although most survivors' function recover to some degree, many of them left with significant sensorimotor or cognitive deficits. These problems produce long-term need for assistance from caregivers and society. Rehabilitation treatments for the hemiplegias have been paid more and more attention. Clinical data has demonstrated that early movement can reduce secondary thrombo-embolic events, pneumonia and mortality in the acute phase. Many clinical data manifested that forcing use affected upper-extremity (UE) can improve function, with obviously imaging features of brain functional reorganization. It is hinted that only using unaffected UE can make "learned nonuse" of affected UE. "Learned nonuse" can be reclamated by forcing use affected UE. Therefore, the effect of constraint-induced movement(CIM) therapy in patients with sequela of cerebral infarction has been confirmed gradually in recent years. But the study of CIM therapy in the early stage of stroke was rare. It is not clear how does it affect on the recovery of extremity function, what are the mechanisms? That leads to the limitation in application of CIM therapy. The purpose of the study is to explore the effects and the mechanisms of CIM therapy for the victims at the early stage using MCAO. After model of middle cerebral artery occlusion (MCAO) had been made successfully, rats were randomly assigned and immobilizated either the ipsilateral or contralateral forelimb ,respectively, or left uncasted . A battery of behavioral tests was administered. And the expression of MAP-2 and NCAM in the peri-ischemic cortex were detected with immunohistochemistry or in situ hybridization. Methods: The 79 rats were randomly assigned into: sham-operated group (group D n=13) and operated group(n=66). A model of MCAO was made by occluding MCA with electric coagutation. At 24 hours after lesion, the 60 rats were randomly assigned into three groups: Lesion+Contra (to the lesion) cast (group A n=20); Lesion+No cast (group B n=20); Lesion+Ipsilateral cast (group C n=20). The cast were removed at day 21 postsurgery. The rats were also randomly assigned to be killed at one of two time points: on day 21 or day 28 postlesion after evaluated balance function, posture reflex and muscle strength. The expression of MAP-2 and NCAM in the peri-ischemia cortex was examined by using immunohistochemistry straining or in situ hybridization at the same time with the evaluation.Results: At 24 hours after the MCAO, severe impairment of function occurred in the group on operation, but there were no difference among group A, B and C. Although the function of MCAO rats recovered obviously at day 21 and day 28 after lesion, but still worse than that of group D (P<0.01). Group C performed worse ability on posture reflex and balance at day 21 postlesion than group A and group B (P<0.05,P<0.01). Group C performed worse than group B at day 28 (P<0.05). There were no significant differences within MCAO groups on day 21 and day 28 in muscle strength test.The expression of MAP-2 in the peri-ischemia cortex: In MCAO groups the number of MAP-2 labeled cells decreased significantly, but the expression of MAP-2 increased, in comparison with group D (P<0.05). On the 21th day after surgery, the number of MAP-2 labeled cells and the expression of MAP-2 in group B were higher than those in group A and group C (P<0.05,P<0.01); those in group A were higher than those in group C (p<0.05). On the 28th day, the number of MAP-2 labeled cells and the expression of MAP-2 in group C were lower than those in group A and group B (P<0.05,P<0.01). There were no significant differences between group A and group B (P>0.05).The expression of NCAM detected with immunohistochemistry or in situ hybridization in the peri-ischemia cortex: The number of NCAM labeled cells and the expression of NCAM increased significantly after MCAO in MCAO group than those in group D (P<0.05). On the 21th day at postsurgery, the number of NCAM labe... |
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