鼠侧向液压脑损伤后脑血流量和葡萄糖利用率的改变

Changes in cerebral blood flow and glucose utilization following fluid percussion brain Injury in rats

目的：探讨液压冲击脑损伤后脑血流量（ＣＢＦ），局部脑血流量（ｒＣＢＦ）与局部葡萄糖利用率（ｒＣＧＵ）的变化及其对神经元继发性损伤的影响。方法：应用激光多普勒流量计和定量放射自显影技术。结果：液压冲击脑损伤导致６０秒内ＣＢＦ短暂升高然后显著下降，且持续６０分钟低于正常，同侧和对侧大脑半球的ＣＢＦ相应降为正常值的７９％和９３％。外伤后１小时，损伤侧脑皮层，丘脑及海马的ｒＣＢＦ下降１２％～５９％，对侧大脑半球相应区域则下降１０％～４０％。相反，ｒＣＧＵ在冲击区周围脑皮质及同侧丘脑和海马区升高２７％～１０１％，在对侧大脑半球相应区域则升高２０％～９１％，海马区由液压冲击引起的ｒＣＢＦ和ｒＣＧＵ分离性变化十分显著，同侧海马ＣＡ１和ＣＡ２－３区存活的神经元数量在损伤后两星期时显著减少。结论：ｒＣＢＦ和ｒＣＧＵ的分离性变化是引起外伤后神经元尤其是海马区神经元继发损伤的主要因素。

Objective: To study the relationship between changes of regional cerebral blood flow (rCBF) and regional cerebral glucose utilization (rCGU) following lateral fluid percussion injury in rat model. Methods: Laser Doppler fowmeter and quantitative autoradiography (14C4iodNMethylantipyrine and 14C2DeoxyDGlucose technique) were used. Result: The inflicted trauma produced a transient increase in CBF followed by marked decrease within 60 seconds, and CBF remained depressed over 60 minutes, at approximately 79% and 93% of baseline in ipsilateral and contralateral hemisphere respectively. On the end of 1 hour following injury, rCBF and rCGU were mapped by quantitative autoradiography. Consist with CBF monitoring, rCBF decreased considerably in cerebral cortex, thalamus and hipocamppus of ipsilateral (12%～59%) and contralateral hemisphere (10%～40%). In contrast rCGU increased considerably in cerebral cortex surrounding impact site, thalsmus and hippocampus of ipsilateral (27%～10%) and contralateral hemisphere (20%～91%). The effect of fluid percussion injury was pronounced in hippocampus as a uncoupling changes between rCBF and rCGU. The number of surviving neuronal cells of CA1 and CA23 in ipsilateral hippocampus decreased signigficantly 2 weeks after injury. Conclusion: The results indicate that secondary insults such as uncoupling changes between rCBF and rCGU may vulnerable to traumatized neurons especially in hippocampus.