摘要
目的:研究创伤性脑损伤后神经细胞凋亡机理及其时序空间分布,并探讨亚低温脑保护机理。方法:末端标记法(TUNEL)、琼脂糖凝胶电泳、流式细胞技术检测大鼠重度脑损伤后不同脑区神经细胞凋亡的动态变化过程。实验分假手术组、常温脑伤组、亚低温治疗6、12、24h 三组。结果:创伤后12h 皮层、皮层下、白质、海马等脑区神经细胞凋亡明显增加,其高峰在伤后12～72h,持续可达14d,与对照组相比较,相差显著或非常显著。琼脂糖凝胶电泳显示创伤脑组织 DNA 出现特异凋亡电泳带。流式细胞检测呈现典型亚二倍体核型峰(AP 峰)。亚低温治疗明显抑制创伤性神经细胞凋亡。结论:创伤性脑损伤后存在神经细胞凋亡现象。亚低温对创伤性神经细胞凋亡具有明显抑制作用。
Objective:To study the mechanisms of posttraumatic neuronal apoptosis and the protective effect of mild hypothermia on posttraumatic brain in the rats.Methods:By using the terminal deoxynucle- tidyl transferase mediated deoxyuridine 5'-triphosphate-bioin nick end labeling technique(TUNEL),agar- ose gel electrophoresis and flow cytometric analysis,the dynamic change in the processes of neuronal ap- optosis in the different brain regions of the rats subjected to severe traumatic brain injury(TBI)were se- quentially examined.The animals were randomly divided into three groups:①sham;②rats with head inju- ry,kiUed at 12,24,48,72,168,336 hours after TBI;③rats with head injury,treated by mild hypothermia at 32℃ for 6,12 and 24 hours respectively.Results:The apoptotic cells could be detectable in the cere- bral cortex,subcortex,white matter and the hippocampus 12 h～14 d after TBI and reached the peak at approximately 12～72h.The apoptotic cells in the above-mentioned brain areas significantly increased in the rats with brain injury compared with the control group(P<0.05).Agarose gel electrophoresis showed specific apoptotie zone,and a typical DNA ladder could be revealed by the flow cytometric analysis in the rats with brain injury.In the rats with brain injury treated by mild hypothermia,the apoptotic cells were significantly fewer than those in the rats with brain injury who were not treated by the mild hypothermia (P<0.05).Conclusion:The data suggest that apoptosis would occur after TBI.The mild hypothermia may exert favorable effect on inhibition of apoptotic cell death.
