一氧化氮与蛛网膜下腔出血后早期脑损伤所致脑微循环变化的相关性研究

目的观察蛛网膜下腔出血（SAH）后早期脑微循环的变化及SAH后一氧化氮（NO）的表达对早期脑损伤（EBI）及脑微循环的影响。方法80只新西兰大白兔分为手术组和假手术组，2组再分为术后1、6、24、72 h 4个亚组，各10只。手术组采用枕大池注血法制备兔SAH模型，假手术组采用相同方法注射0.9%氯化钠溶液制备模型。然后行全脑CT灌注成像，比较各组血流量（CBF）、血容量（CBV）、平均通过时间（MTT）、达峰时间（TTP）、NO含量，并分析NO与CBV、CBF、MTT、TTP相关性。结果手术组CBV与CBF在术后1、6、24、72 h均明显低于假手术组（P<0.01），MTT高于假手术组（P<0.05~P<0.01）；手术组TTP在术后24 h和72 h均高于假手术组间（P<0.01和P<0.05）。假手术组在术后1、6、24、72 h NO含量无明显变化（P>0.05），手术组兔在术后24 h和72 h NO含量有所回升（P<0.01）；术后1、6、24、72 h手术组NO含量均明显低于相应假手术组（P<0.01）。直线相关分析显示，手术组NO与MTT呈负相关关系（r=-0.854，P<0.05），与CBF呈正相关关系（r=0.786，P<0.05）。结论CT灌注能早期发现SAH后局部脑缺血，反映SAH后EBI的病理进展程度。NO一定程度上影响SAH后微循环的改变及EBI的进展程度。

Correlation between nitric oxide and cerebral microcirculation changes caused by early brain injury after subarachnoid hemorrhage

ObjectiveTo observe the changes of early cerebral microcirculation after subarachnoid hemorrhage (SAH) and the effect of nitric oxide (NO) expression on early brain injury (EBI) and cerebral microcirculation after SAH.MethodsEighty New Zealand white rabbits were divided into the operation group and sham operation group, then the two groups were further divided into 4 subgroups including 1 h, 6 h, 24 h and 72 h after operation, with 10 rabbits in each subgroup.SAH model was established by injecting autologous blood into cisterna magna in operation group, and injecting 0.9% sodium chloride solution with the same method in sham operation group.The CT perfusion imaging of whole brain was performed to compare the cerebral blood flow(CBF), cerebral blood volume(CBV), mean transit time(MTT), time to peak (TTP) and NO content in each group, and the correlation between NO and CBV, CBF, MTT, TTP was analyzed.ResultsCBV and CBF in operation group were significantly lower than those in sham operation group at 1 h, 6 h, 24 h and 72 h after operation (P<0.01), and MTT was higher than that in sham operation group(P<0.05 to P<0.01);TTP in operation group was higher than that in sham operation group at 24 h and 72 h after operation(P<0.01 and P<0.05).There was no significant change in the NO content at 1 h, 6 h, 24 h and 72 h after operation in sham operation group(P>0.05), but the NO content increased at 24 h and 72 h after operation in operation group(P<0.01);at 1 h, 6 h, 24 h and 72 h after operation, the NO content in operation group was significantly lower than that in the corresponding sham operation group(P<0.01).Linear correlation analysis showed that NO was negatively correlated with MTT(r=-0.854, P<0.05) and positively correlated with CBF(r=0.786, P<0.05).ConclusionsCT perfusion can detect the focal cerebral ischemia after SAH in early stage, which reflects the pathological progress of EBI after SAH.NO affects the microcirculation changes and the progress of EBI after SAH to some extent.