| Objective: to study the AQP4 expression after cerebral ischemia in rats and its correlation with the outcome of 1H MRS. Methods: Adult Wistar rats of either sex, clean grade, with body mass of 180～210g , were randomized into the control group(n=8), the shamed operated group(n=8) and the cerebral ischemic group(n=32), in which the cerebral ischemic group were divided into 4 different groups at the time points of 6h, 1d, 3d and 7d (n=8, respectively), nothing was done except for anesthetizing in control group, the filament was just inserted into the internal carotid artery in the shamed operated group, 1HMRS was performed in cerebral ischemic and shamed –operated group at the time point of 6h,1d,3,7d after cerebral ischemia, and in the control group at the same time point. Then immunohistochemistry, RT-PCR and Western Blot analysis were employed to study the AQP4 expression. Results: The increase in Lac was present 6h after cerebral ischemia and up to the highest level at 24h and a partial recover of reduction was visible at 3d. A reduction in NAA was observed at 6h post-infarction, and the maximal decrease occurred at 24h, at 3d NAA began to rise and closed to normal level at 7d. Significant differences in Lac and NAA in cerebral ischemic group were indicated compared with those in the homologous area of the contralateral hemisphere and in control group (P<0.05). No obvious change of bilateral ADC values was found between the control and the shamed-operated groups, ADC values started to decrease at 6h after cerebral ischemia, then gradually rise and maintain the increasing trend. Compared with the control group, no significant difference was observed(P<0.05).The AQP4 expression was not significant in the control and shamed-operated groups using immunohistochemistry, RT-PCR and Western Blot(P>0.05).The AQP4 expression started to increase 6h post infarction in rats, and the highest level was detected at 1d, after a slight increase at 3d, a gradual recovery of reduction appeared at 7d. Compared with the control group, significant difference was found (P<0.05). there was no apparent correlation between the AQP4 expression and the Lac consistently indicated by immunohistochemistry, RT-PCR and Western Blot(rih =0.568, rW =0.574, rRT=0.609, P>0.05),however, a significantly negative correlation existed between the NAA and AQP4(rih =-0.966, rRT =-0.957, rW=-0.974, P<0.05) and between the ADC and AQP4 1d post infarction in rats(rih =-0.991, rRT =-0.994, rW=-0.998, P<0.05), a poor correlation between Lac and ADC(r=-0.731, P>0.05)and a good correlation between NAA and ADC were also indicated (r=0.995, P<0.05). Conclusion:Cytotoxic edema was predominantly present at 6h and vasogenic edema at 1d after cerebral ischemia in rats. AQP4 plays for an important role in the cerebral edema formation and resolution. Lac is a sensitive indicator in the early stage of cerebral ischemia and was not associated with vasogenic edema. However, NAA was associated with vasogenic edema and the disruption of blood brain barrier (BBB). Objective: To study the metabolite concentration abnormalities in rat model of middle cerebral artery occlusion (MCAO) with 1H MRS Methods: Adult Wistar rats of either sex, clean grade, with body mass of 180～210g , were randomized into the control group, the shamed operated and the cerebral ischemic groups, the permanent cerebral ischemic model was induced by occluding the right internal carotid artery in cerebral ischemic group and the filament were just inserted into the internal carotid artery, nothing was done except for anesthetizing in the control group. 1H MRS was performed within the area of cerebral infarction and the homologous area of the contralateral hemisphere using 1.5T GE signa Highspeed NMR spectrometer in cerebral ischemic and shamed –operated group at the time point of 30min,1,3,6,12,24h,3,7,15d,1,2months after cerebral ischemia, and in the control group at the same time point. Results: (1) In the normal group, bilateral metabolites were symmetrically distributed; No signific...
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