小剂量异丙酚对内毒素孵育兔肺动脉及体动脉血管的影响

The effect of small dose propofol on the tone of rabbit pulmonary artery and chest aorta after LPS induction

目的：观察小剂量异丙酚（Propofol，PF）对内毒素（LPS）致感染性休克兔外周血管阻力（SVR）、阻力指数（SVRI）、胸腔液体量（TFC）以及离体肺动脉环和胸主动脉环张力的影响。研究小剂量异丙酚对感染性休克兔的保护作用及可能机制。方法选择健康成年雄性大耳兔20只，体重2.5～2.8kg，随机分为正常组（N组）和LPS 致休克模型组（L组），再以两种不同小剂量（50μmol/L和100μmol/L）异丙酚对两组分别进行干预，每项干预5只。用胸电生物阻抗法血液动力学连续监护系统（Bioz）测量各组SVR、SVRI和TFC，之后制备离体肺动脉环和主动脉环，连接张力换能器，观察各组血管环张力的变化。结果干预前与N组相比，L组SVR、SVRI下降，TFC升高（P〈0.05），肺动脉环张力有所下降，但不如主动脉环张力下降明显（P〈0.05）。与干预前相比，L组SVR、SVRI均有所升高（P〈0.05），100μmol/L剂量下同时还伴有TFC下降（P〈0.05）。离体条件下50μmol/L剂量时仅增加主动脉环对PE的反应性（P〈0.05），100μmol/L剂量下在增加主动脉张力的同时，还能降低肺动脉张力，使肺动脉与主动脉环张力比值（P/A 值）降低（P〈0.05）。结论小剂量异丙酚（50μmol/L 和100μmol/L）通过直接作用于血管壁调节血管张力，增加感染性休克兔主动脉血管张力，维持体循环稳定。其中100μmol/L的PF不但增加主动脉张力，还能降低肺动脉张力，更能有效纠正血管舒缩状态，改善组织灌注，对感染性休克兔的血管具有保护作用。

Objective To observe the effect of propofol （PF） in small dose on the tone of alive rabbit systemic vascular resistance/index （SVR/SVRI）,thoracic fluid content （TFC） and isolated rabbit pulmonary artery and chest aorta rings before and after LPS （lipopolysaccharide） incubation, approach the protection function and possible mechanism of propofol （PF） in small dose on the sepsis rabbit. Methods 20 healthy adult masculinity big ear rabbits with weight about 2.5～2.8kg were selected and randomly divided into two groups：normal group（N group） and LPS induced septic shock group （L group）, and two different small doses PF （50μmol/L and 100μmol/L） intervented each group randomly,n=5. Surveyed the SVR,SVRI and TFC of two groups by electrobiology impedance hemodynamic measure system. The rabbits were anaesthesized by isoflurane and prepared the isolated pulmonary artery and chest aorta rings. Joined the isolated vascular rings into the tension energy transducer to ob-serve the effect of PF in different dose on the tone of isolated rabbit pulmonary artery and chest aorta rings before and after LPS incubation. Results Compared with N group before intervation, SVR,SVRI decreased and TFC increased in L group （P〈0.05）. The tension of pulmonary artery rings decreased, but the decrease amplitude was smaller than that of aorta rings after LPS incubation （P〈0.05）. After intervention, SVR and SVRI in L group increased, and TFC decreased when PF was 100μmol/L. In the isolated rabbits, 50μmol/L PF only increased the tension of chest aorta rings（P〈0.05）,100μmol/L PF not only decreased the tension of pulmonary artery rings, but also increased the tension of chest aorta rings, which decreased the ratio of the tension of pulmonary and aorta（P/A）, P〈0.05. Conclusion Small dose of propofol （50μmol/L and 100μmol/L） can directly act on the;vessel wall and regulate vascular tone, increase the aortic vascular tension and maintain the homeostasis of systemic circulation of infection shock rabbit. The 100μmol/L PF not only increase aortic tension, but also decrease the pulmonary artery pressure, can effectively correct the vasomotion, impove tissue perfusion, has protective effect on infection shock rabbit vascular.