MRI法评价氯胺酮对创伤性脑外伤小鼠的脑保护作用

Evaluation of ketamine-induced cerebral protection in mice with traumatic brain injury by magnetic resonance imaging

目的采用MRI法评价氯胺酮对创伤性脑外伤（TBI）小鼠的脑保护作用。方法清洁级健康雄性C57BL/6小鼠32只，8周龄，体重26～30 g，采用随机数字表法分为4组：正常对照组（C组，n＝7）、氯胺酮组（K组，n＝7）、TBI组（n＝9）和TBI＋氯胺酮组（TBI＋K组，n＝9）。采用气压颅脑外伤撞击仪制备TBI模型。TBI＋K组、K组于术后1 h腹腔注射氯胺酮150 mg/kg，TBI组和C组给予等量生理盐水。于术后24 h、72 h、7 d时进行旷场实验。于术后6、24和72 h时，TBI组和TBI＋K组行MRI（T1加权）扫描，C组和K组于术后24 h时行MRI扫描，观察小鼠脑水肿情况。结果C组和K组MRI扫描未见脑水肿发生，TBI组和TBI＋K组均发生不同程度脑水肿。与C组比较，TBI组术后24、72 h时运动距离缩短（P〈0.05）；与TBI组比较，TBI＋K组脑水肿面积减小，术后24、72 h时运动距离延长（P〈0.05或0.01）。结论MRI法进一步明确了氯胺酮对TBI小鼠可产生一定程度的脑保护作用。

Objective To evaluate ketamine-induced cerebral protection in mice with traumatic brain injury （TBI） by magnetic resonance imaging （MRI）.Methods Thirty-two pathogen-free healthy male C57BL/6 mice, aged 8 weeks, weighing 26-30 g , were divided into 4 groups using a random number table： control group （group C, n=7）, ketamine group （group K, n=7）, TBI group （n=9） and TBI plus ketamine group （group TBI＋ K, n=9）. TBI was produced with a pneumatically driven controlled cortical impact device.Ketamine 150 mg/kg was intraperitoneally injected at 1 h after operation in TBI＋ K and K groups, while the equal volume of normal saline was given instead in TBI and C groups.Open field test was conducted at 24 h, 72 h and 7 days after operation.The animals in TBI and TBI＋ K groups were scanned by T1-weighted MRI at 6, 24 and 72 h after operation, the animals in C and K groups were scanned by MRI at 24 h after operation, and the development of cerebral edema was observed.Results MRI scan showed no cerebral edema in C and K groups, and different degrees of cerebral edema were found in TBI and TBI＋ K groups.Compared with group C, the locomotor distance was significantly shortened at 24 and 72 h after operation in group TBI （P〈0.05）. Compared with group TBI, the size of cerebral edema was significantly decreased, and the locomotor distance was prolonged at 24 and 72 h after operation in group TBI＋ K （P〈0.05 or 0.01）.Conclusion MRI method further clarifies that ketamine can produce cerebral protection to some extent in mice with TBI.