高压氧对脑缺血模型兔脑前后循环血管内皮素-1、内皮型一氧化氮合酶及内皮素A受体表达的影响

Effects of hyperbaric oxygen on the expressions of endothelin-1, endothelial nitric oxide synthase and endothelin A receptor in cerebral circulation blood vessel in the rabbit model of cerebral ischemia

目的探讨高压氧（hyperbaric oxygen, HBO）对脑缺血兔模型脑前后循环血管内皮素-1（endothelin-1，ET-1）、内皮型一氧化氮合酶（endothelial nitric oxide synthase，eNOS）及内皮素A受体（endothelin A receptor，ETAR）表达的影响。方法选取健康成年新西兰家兔40只，按随机数字表法分为手术组30只和假手术组10只，其中手术组30只按治疗方法再分为高压氧脑缺血组15只和脑缺血组15只。手术组通过线栓法建立大脑中动脉脑缺血模型，高压氧脑缺血组暴露于0.22 MPa（2.2 ATA）高压氧下60 min，1次/d，连续3 d；假手术组仅分离颈部血管后缝合颈部切口，假手术组和脑缺血组家兔不予高压氧暴露，饲养3 d。所有家兔3 d后处死，使用ET-1抗体、eNOS抗体、ETAR抗体行免疫组化切片染色，观察脑前后循环血管ET-1、eNOS、ETAR在3组家兔中的颈内动脉和基底动脉表达情况。结果脑前后循环血管ET-1、eNOS、ETAR在3组家兔中的颈内动脉和基底动脉均有表达。与假手术组、脑缺血组相比，高压氧脑缺血组ET-1、ETAR受体在颈内动脉表达（51.6±2.1、53.4±1.5）较基底动脉（20.3±2.6、24.3±1.7）明显增多，eNOS在基底动脉（52.1±2.3）表达较颈内动脉（22.3±1.2）明显增多，差异均有统计学意义（P〈0.05）。结论HBO暴露可以使脑缺血家兔颈内动脉缩血管因子ET-1、ETAR表达增强，基底动脉舒血管因子eNOS表达增强，引起前循环收缩、后循环扩张。

ObjectiveTo investigate the effects of hyperbaric oxygen （HBO） on the expressions of endothelin-1（ET-1）, endothelial nitric oxide synthase（eNOS）and endothelin A receptor（ETAR）in cerebral circulation blood vessel in the rabbit model of cerebral ischemia. MethodsForty healthy adult New Zealand rabbits were randomly divided into 2 groups; the surgical group （n=30） and the control group （n=10）. The rabbits in the surgical group were further divided into the HBO ＋ cerebral ischemia group （n=15） and the simple cerebral ischemia group （n=15） in accordance with different treatment methods. In the surgical group, cerebral ischemia model was established by thread embolus method. The HBO ＋ cerebral ischemia group was exposed to HBO at a pressure of 0.22 MPa（2.2 ATA）for 60 minutes, one session a day, for a succession of 3 days. In the sham surgical group, neck vessel was only separated and the incision was soon sutured. The animals in the sham surgical group and the cerebral ischemia group did not receive HBO exposure, had normal diet and left there intact for 3 days. Three days later, all the animals were sacrificed, and then immunohistochemical staining was performed by using ET-1, ETAR and eNOS antibodies, and observations were made on the expressions of ET-1, eNOS and ETAR in the internal carotid artery and basilar artery of the 3 groups.ResultsExperimental results indicated that there were expressions of ET-1, eNOS and ETAR in the internal carotid artery and basilar artery after HBO exposure. As compared with those of the sham surgical group and the cerebral ischemia group, the expression levels of ET-1 and ETAR in the internal carotid artery （51.6±2.1, 53.4±1.5）of the HBO ＋ cerebral ischemia group were obviously higher than those in the basilar artery（20.3±2.6, 24.3±1.7）, and eNOS expression level in the basilar artery（52.1±2.3） was significantly higher than that in the internal carotid artery（22.3±1.2）.ConclusionsHBO exposure could enhance ET-1 and ETAR expression levels in the internal carotid artery, and could improve eNOS expression in basilar artery, resulting in anterior circulation contraction and posterior circulation dilation.