EDHF在兔蛛网膜下腔出血模型中对血管内皮依赖性舒张作用的研究

Role of endothelium-derived hyperpolarizing factor mediates endothelium-dependent dilation effects in rabbit subarachnoid hemorrhage model

目的探讨内皮依赖性舒张因子(EDHF)在蛛网膜下腔出血(SAH)模型中对血管内皮依赖性舒张作用的变化及其机制。方法 SAH组及正常组各8只,实际应用32个动脉环,分为4组,正常兔基底动脉作为对照,观察兔SAH基底动脉环在L-NAME与Indo存在的情况下,PE预收缩后ACh介导舒张性的改变,观察EDHF对SAH基底动脉舒张功能的改变,以及加入缝隙连接阻断剂CBX预处理动脉环的情况下,进一步观察EDHF介导的舒张功能变化,探讨EDHF是否通过GJ调节血管的舒缩功能。反应特征表述为最大松弛百分率(Rmax)和产生一半最大松弛百分率时所需要ACh浓度的负对数(p IC50)。Two-way ANOVA和t检验分析组间差异。光学显微镜观察SAH基底动脉内皮结构的改变。结果正常兔基底动脉Rmax和p IC50分别为94%±1.2%和8.23%±0.16%,SAH基底动脉Rmax和p IC50分别为36%±1.8%(P<0.001)和6.35%±0.45%(P<0.05)。EDHF在正常兔基底动脉,Rmax和p IC50分别为34%±2.4%和6.12%±0.83%,在SAH Rmax和p IC50分别为13%±1.2%(P<0.01)和3.45%±0.27%(P<0.01)。甘珀酸预处理后,EDHF在正常兔基底动脉,Rmax和p IC50分别为16%±1.2%和3.38%±0.24%,在SAH Rmax和p IC50分别为12%±1.5%(P>0.05)和3.25%±0.13%(P>0.05)。形态学观察显示SAH基底动脉出现部分内皮细胞脱落,内弹力膜不完整,有断裂现象。结论 EDHF在SAH模型中介导的舒张作用减弱;血管内皮的损伤及肌内皮缝隙连接的改变可能是引起SAH后EDHF介导的舒张作用减弱的重要机制。

Objective To investigate the effects of endothelium-derived hyperpolarizing factor-mediated vasodilation induced by Ach in rabbit subarachnoid hemorrhage model. Methods Compared with normal rabbit＇ s basilar arteries, model was treated with the nitric oxide synthase inhibitor L-NAME and Indo in the rabbit＇ s basilar arterial rings, the acetylcholine-induced dilation changes were observed following the Phenylephrine＇ s preshrinking, then the EDHF-mediated diastolic function in the SAH basilar artery was inspected. Besides, add gap junctional blocker Carbenoxoline to predispose the arterial rings, then to observe the EDHF-mediated dilation changes and to learn whether the gap junctional blocker could regulate the vascular＇ s diastolic and systolic function. Response character was expressed by Rmax and pIC50 to analyze the difference between the group by Two-way ANOVA and T test. The construction change was observed by light microscope in the SAH basilar artery＇ s endothelium. Results The Rmax value and pIC50 value of the normal rabbit basilar artery was 94% ±1.2% and 8.23 % ±0.16% respectively ,while the SAH was 36% ± 1.8% （ P 〈 0. 001 ） and 6.35% ± 0. 45% （ P 〈 0. 05）,respectively. With the EDHF in the normal rabbit basilar artery,the value of Rmax and pIC50 was 34% ±2.4% and 6.12% ±0.83% ,while with the EDHF in the SAH,the value of Rmax and pIC50 was 13% ± 1.2% （P 〈0.01 ） and 3.45% ±0.27% （P 〈0.01 ）,respectively. Carbenoxoline to predispose the arterial rings,the EDHF in the normal rabbit basilar artery,the value of Rmax and pICSO was 16% ± 1.2% and 3.38% ±0.24% ,while with the EDHF in the SAH ,the value of Rmax and pICS0 was 12% ± 1.5% （ P 〉 0. 05 ） and 3.25% ± 0.13% （ P 〉 0. 05 ） , respectively. Morphological analysis showed that the SAH basilar artery＇ s endothelial cells were partly desquamating, and it＇ s elasticity intra-membrane was also not in integrity,turning out to break. Conclusion EDHF-mediated diastolic function decrease in the SAH model＇ s basilar artery, However the impairion of endothelium and myoendothelial coupling may cause the EDHF-mediated vasodilation decreased in SAH.