动态对比增强磁共振评估阑尾切除术后小鼠血脑屏障通透性的实验研究

The experimental study of dynamic contrast-enhanced magnetic resonance imaging in assessing the permeability of blood-brain barrier in mice after appendectomy

目的 探讨动态对比增强磁共振(DCE-MRI)无创评估剖腹阑尾切除小鼠的血脑屏障(BBB)通透性改变.方法 采用D-gal药物催老小鼠的模型,将小鼠随机分为老年手术组、老年对照组、青年手术组和青年对照组行剖腹阑尾切除术.采用反转式Morris水迷宫和新物体实验观察小鼠围术期认知的改变,采集动态对比增强磁共振成像(DCE-MRI),测量Ktrans值变化,并和小鼠海马的荧光素钠渗透率进行相关性分析,最后用电镜观察验证血脑屏障破坏情况.结果 与青年小鼠和对照组小鼠相比,老年小鼠仅术后第2天出现水迷宫潜伏期显著延长,各组小鼠术后第7天新物体分辨指数差异无统计学意义(P=0.68);磁共振提示Ktrans值术后短期增加,术后第2天与第7天Ktrans与荧光素钠渗出相关系数分别为0.984和0.825.结论 老年小鼠阑尾手术后认知功能的改变与血脑屏障的恢复相关,MRI能早期无创评估围术期血脑屏障的改变.

Objective To explore the dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)noninvasive evaluation of bloodbrain barrier(BBB)penneability in mice with appendectomy.Methods The D-gal induced aging mice model was applied.The mice were randomly divided into the elderly operation group,the elderly control group,the young operation group and the young control group.Morris water maze as well as object recognition test were used to detect the changes of perioperative cognition.Dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)was pcrfcimied,and measure the changes of Ktrans value and perfonn correlation analysis with the permeability of fluorescein sodium in mice hippocampus.Electron microscope was used to observe the damage of blood-brain barrier.Results Compared with young mice and non laparotomy mice,the latency of water maze was prolonged and the Ktrans value was increased in old mice on the second day after openition,and there was no significant difference in the new object discrimination index between these four groups on the 7th day after operation(P=0.68).MKI showed that the value of Ktrans was short-temi increased after surgery,and the correlarion coefficients between Ktrans and fluorescein sodium exudation were 0.984 and 0.825 on the second day and the seventh day after operation,respectively.Conclusion The changes in cognitive ftinction after appendix surgery in aged mice are associated with restoration of the blood-bniin barrier,and MRI can be used for noninvasive in vivo evaluation of the permeability changes ofblood-brain barrier in aged mice after appendectomy.