磁化传递成像早期评估大鼠心肺复苏后脑损伤研究

Magnetization transfer imaging for early assessment of brain injury after cardiopulmonary resuscitation in a rat cardiac arrest model

目的:探讨磁化传递成像(MTI)早期评估窒息大鼠心搏骤停模型复苏(CA/CPR)后脑损伤的可行性。方法:将14只大鼠分为假手术组(6只)与模型组(8只),使用气管插管法制作大鼠CA模型,两组大鼠恢复自主循环(ROSC)6 h后行MTI扫描,并测量两组大鼠脑干、小脑、海马及顶叶皮质磁化传递脉冲的信号强度(Ms),并计算磁化传递率(MTR)。MTI扫描完成后将大鼠处死并取脑组织切片行AQP4免疫组织化学染色。比较两组大鼠脑干、小脑、海马及顶叶皮质Ms与MTR差异。结果:模型组6只大鼠建模成功,2只失败。模型组大鼠脑干、小脑、海马及顶叶皮质Ms均低于假手术组,两组差异有统计学意义(P<0.05);模型组测量的各个区域MTR明显高于假手术组,两组差异有统计学意义(P<0.05)。假手术组大鼠脑干、小脑、海马及顶叶皮质AQP4抗体表达阴性;模型组大鼠脑干、小脑、海马及顶叶皮质AQP4抗体表达阳性。结论:MTI技术可早期用于CA/CPR后脑损伤评估,Ms及MTR为敏感反映脑水肿的定量指标。

Objective: To investigate the feasibility of magnetization transfer imaging(MTI) for early assessment of brain injury after cardiopulmonary resuscitation(CPR) in a rat model of cardiac arrest. Methods: Fourteen rats were divided into sham group(n=6) and model group(n=8). The rat CA model was established by tracheal intubation. The two groups of rats underwent MTI 6 hours after recovery of spontaneous circulation(ROSC). Scan and measure the signal strength of magnetization transfer pulses(Ms) in the brainstem, cerebellum, hippocampus and parietal cortex of the rats of two groups, and calculate the magnetization transfer rate(MTR). After the MTI scan, the rats were sacrificed and brain tissue sections were taken for AQP4 immunohistochemical staining. Differences of Ms and MTR in the brainstem, cerebellum, hippocampus and parietal cortex of the two groups of rats were compared. Results: In the model group, 6 rats were successfully resuscitated, and 2 rats failed. The Ms in the brainstem, cerebellum, hippocampus and parietal cortex of the model group was lower than that of the sham group, and the MTR of the model group was higher than that of the sham group.The expression of AQP4 in the brainstem, cerebellum, hippocampus and parietal cortex of rats in the sham group was negative;the expression of AQP4 antibody in the brainstem, cerebellum, hippocampus and parietal cortex of rats in the model group was positive. Conclusion: MTI technology can be used for early assessment of brain injury after CA/CPR. Ms and MTR are sensitive quantitative indicators reflecting brain edema.