犬颅脑损伤后早期细胞内钙离子与c-Fos表达的变化

Changes of intracellular calciumions and c-Fos expression in canines with craniocerebral injury

目的:探讨犬颅脑枪弹伤后细胞内Ca2+与c-Fos表达变化的规律。方法:实验于2002-03解放军第四军医大学西京医院实验外科地下靶道进行。以德国小口径步枪子弹致伤犬颅脑贯通伤模型为对象,采用免疫组化法检测脑组织及伤后不同时间弹道挫伤区中c-fos基因的表达。制备脑组织的活细胞悬液进行原代培养;应用特异性Ca2+荧光指示剂Fluo-3/AM标记,在激光扫描共聚焦显微镜下检测伤后不同时间弹道挫伤区细胞内Ca2+分布情况。结果:弹道挫伤区神经元中c-fos基因表达于伤后30min开始增加(P<0.05),2h达到高峰(32.4±2.4,P<0.01),6h逐渐下降。培养得到了贴壁的犬颅脑火器伤后的脑组织活细胞。并观察到伤后30min细胞内Ca2+开始升高(P<0.05),持续升高到伤后6h以上(269.9±2.5)。结论:神经元中Fos表达是由Leao播散性抑制所致。播散性抑制可将细胞外Ca2+转移至细胞内,造成细胞外Ca2+浓度下降,引起皮质神经元去极化,Ca2+内流及神经元去极化均可引起c-Fos表达。

AIM:To study the changes of neuron intracellular Ca2+and c Fos expression after craniocerebral gunshot wounds in canines. METHODS: The experiment was finished at the underground shooting range of the Department of Neurosurgery, Xijing Hospital of Fourth Military Medical University Chinese PLA in March 2002. Using the canine model of craniocerebral penetrating induced by the bullets of the small calibre rifle made in German, the c fos expression in neurons was observed in the contusion area of the trajectory at different time points after trauma by using immunohistochemical method. The living cell suspension of the cerebral tissues was prepared for primary culture. Intracellular Ca2+distribution was measured with calcium fluorescent probes Fluo 3/AM under laser confocal microscope in the contusion area of the trajectory at different time. RESULTS: The c fos expression was increased in neurons in the contusion area of the trajectory after 30 minutes (P < 0.05), which reached to the peak (32.4±2.4) at 2 hours (P< 0.01), and began to decrease at 6 hours after injury.The living cells of the cerebral tissues were cultured successfully after craniocerebral gunshot wounds in canines. It was found that intracellular Ca2+increased obviously within 30 minutes (P< 0.05), and enhanced continually (269.9±2.5) until 6 hours after injury. CONCLUSION: The c Fos expression may be caused by the Leao's spreading depression (SD). SD can transfer the extracellular Ca2+to intracellular,decline the concentration of extracellular Ca2+, and cause cortex neurons depolarization. The c Fos expression in neurons can be aroused by these causes.