静息态功能MRI观察血管性痴呆大鼠模型全脑局部一致性

Resting-state functional MRI observation on regional homogeneity of whole brain in rat models of vascular dementia

目的采用静息态功能MRI(rs-fMRI)评价血管性痴呆(VD)大鼠全脑局部一致性(ReHo)改变,并观察其行为学改变。方法将50只雄性Wistar大鼠分为VD组(n=35)和对照组(n=15)。VD组通过结扎双侧颈总动脉建立VD模型,对照组仅分离其双侧颈动脉。4周后行Morris水迷宫实验,大鼠每日学习2次、持续5日,比较组间逃逸潜伏期的差异。以9.4T MR采集大鼠颅脑rs-fMRI数据,观察组间ReHo值出现变化的脑区。结果对VD组20只大鼠成功建模,对照组10只成功施行假手术。Morris水迷宫实验中,VD组逃逸潜伏期较对照组延长;随学习次数增加,2组大鼠逃逸潜伏期均逐渐缩短,但VD组逃逸潜伏期均长于对照组(P均<0.01)。rs-fMRI结果显示,相比对照组,VD组双侧纹状体ReHo值减低,右侧背外侧内嗅皮层、右侧新脑皮层ReHo值升高(P均<0.05,GFR校正)。结论VD大鼠部分脑区ReHo值与对照组存在差异;双侧纹状体、右侧背外侧内嗅皮层及右侧新脑皮层改变可能与其认知功能下降有关。

Objective To observe the changes in regional homogeneity(ReHo)of whole brain in vascular dementia(VD)rat models with resting-state functional MRI(rs-fMRI),and to evaluate the behavioral changes of VD rats.Methods Fifty male Wistar rats were divided into VD group(n=35)and control group(n=15).VD models were established through ligations of bilateral common carotid arteries in VD group,while the bilateral carotid arteries were only isolated in control group.Four weeks after modeling,Morris water maze experiment was carried out.The rats learned twice a day for 5 days.The escape latencies were compared between the groups.Then data of brain rs-fMRI were collected using a 9.4T MR scanner,brain regions with ReHo value changes between groups were observed.Results VD models were successfully established in 20 rats,while the sham operation was successfully performed in 10 rats in control group.In Morris water maze experiment,the rats in VD group took longer time than those in control group to find the platform.After learning,the escape latency of rats gradually shortened in both 2 groups,but of VD group was still longer than of control group at all points(all P<0.01).Compared with control group,the ReHo values of bilateral corpus striatum,and of right dorsolateral entorhinal cortex and right neocortex increased in VD group decreased(all P<0.05,GFR correction).Conclusion ReHo in brain regions of VD rat models were different from those of controls.ReHo changes of bilateral corpus striatum,dorsolateral entorhinal cortex and right neocortex might be associated with cognitive decline.