Objective:Using T2-weighted imaging(T2WI),diffusion-weighted imaging(DWI),pulsed gradient spin echo(PGSE)multiparametric magnetic resonance imaging combined with various histopathological techniques to observe the effects of reperfusion after different times of cerebral ischemia(CIRI)on the cytotoxic edema of brain tis-sues in rats.This provides a solid foundation for the establishment of ischemic stroke models and clinical diagnosis and treatment.Methods:Healthy adult male Sprague Dawley rats were randomly allocated to four groups:the sham-opera-ted(Sham)group,the ischaemia 60 min reperfusion(IR-60 min)group,the IR-120 min group,and the IR-180 min group.CIRI rat model was prepared by modified Zea Longa method.Laser doppler flowmetry combined with hematoxy-lin-eosin(HE)staining was employed to identify the model.Multiparametric magnetic resonance imaging,combined with water content of brain,immunofluorescence staining of aquaporin-4(AQP4),and Western Blot were performed to observe cytotoxic edema of brain tissues and tumour necrosis factor alpha(TNF-α),interleukin 1β(IL-1β)in brain tissue of rats in each group.Results:HE staining and determination of brain tissue water content prove that as ischemia time prolongs,the degree of cerebral cortex edema on the ischemic side increases.The T2WI results showed that the injury in the IR-60 min group began to affect the cerebral cortex,the injury in the IR-120 min group had completely affected the cerebral cortex,and the injury in the IR-180 min group was the most severe(P＜0.05),with a significant shift of the midline of the brain towards the opposite side.The relative apparent diffusion coefficient and water exchange time of the cerebral cortex on the ischemic side of the rats were found to be significantly lower than those of the sham group,with an declining trend(P＜0.05).Additionally,the values of cell membrane permeability of the cerebral cor-tex on the ischemic side of the rats were observed to be significantly higher than those of the sham group in all groups(P＜0.05).The expression of AQP4,IL-1 β and TNF-α in the cerebral cortex of ischemic side was significantly higher than that in the sham group,and showed an upward trend(P＜0.05).Conclusion:Reperfusion following 60,120 and,180 minutes of middle cerebral artery ischemia in rats can result in brain damage.Prolongation of ischemia time has been shown to exacerbate the toxic edema of brain cells and brain damage.Ischemia of 120 minutes reperfusion has been identified as the optimal modeling time for ischemic stroke.Multiparametric MRI can be utilized to monitor the mi-crostructural changes of brain tissue in rats following CIRI in vivo,providing a foundation for the visualization of early clinical diagnosis and treatment.
关键词
多参数磁共振成像(mMRI)/脑缺血再灌注损伤(CIRI)/水通道蛋白4(AQP4)/脑水肿/大鼠
Key words
multiparametric magnetic resonance imaging(mMRI)/cerebral ischemia reperfusion injury(CIRI)/aquaporin-4(AQP4)/cerebral edema/rat
维普
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