血管迷走性晕厥动物模型的建立

Establishment of Animal Model of Vasovagal Syncope

目的拟建立血管迷走性晕厥(VVS)动物模型,为VVS发病机制、病理生理和药物干预的研究提供基础。方法12只健康新西兰大白兔称体质量后,耳缘静脉注射戊巴比妥钠(40mg/kg),麻醉后仰卧位固定于专用兔固定架上。耳缘静脉注射肝素钠注射液1000U(肝素化),无菌条件下右侧股动脉置入导管,连接于有创血压监测管及压力转换器,左侧股动脉置入导管,供抽血用。观察5min后,以5mL/min的速度抽血,连续监测其心率、血压,记录其放血量,直至其血压显著降低或出现抽搐。结果1.心率变化:12只新西兰大白兔基础心率为(305.3±29.1)次/min,经实验(7.6±1.7)min后,心率达到最高值(322.3±27.2)次/min,心率增加(18.2±3.0)次/min,放血量(40.6±3.2)mL。此后随着放血量增加,心率减慢(13.6±1.4)次/min。2.血压变化:12只新西兰大白兔基础血压为(9.99±1.24)kPa,实验初心率增快,但血压无明显变化。随着放血量增加,心率增快,平均血压下降(0.25±0.07)kPa/min,直至心率达到最高值。此后随放血量增加,心率减慢,平均血压下降较前显著,下降(0.85±0.2)kPa/min,直至大白兔角膜反射完全消失,肌肉松弛或出现抽搐、抽泣样呼吸、死亡。总放血量为(55.3±13.5)mL。结论对动物实施失血诱发Bezold-Jarisch反射与人类VVS表现类似,是研究VVS较为合理的模型。

Objective To establish a practical animal model of experimental vasovagal syncope（VVS） that can be used for the study on mechanism, pathophysiology, and intervention of VVS. Methods Twelve healthy grown - up New - Zealand white rabbits were weighted,anes- thetized by pentobarbital（40 mg/kg）intravenously,and placed on a restraining box. The rabbits were observed for 5 minutes and then blood withdrawal was begun. The blood was removed at a rate of 5 mL per minute,heart rate, blood pressure,removing time and the amounts of re- moved blood being recorded every minute. Blood removal was continued until the systolic blood pressure decreased significantly or rabbit died. Results 1. Changes of heart rate ： all rabbits experienced an increase in heart rate from baseline to a maximum value in （ 7.6 ± 1.7 ） min E （305. 3 ± 29.1 ） time per min, （322.3 ± 27.2） time per min, respectively ]. Then heart rate decreased with （ 13.6 ± 1.4） time per min. 2. Changes of blood pressure ： baseline mean blood pressure of the rabbits was （9.99 ± 1.24 ） kPa. At the beginning, blood pressure did not change inspite of heart rate increasing. However, mean blood pressure decreased with continued blood withdrawal even in the presence of in- creasing heart rate at a rate of （0.25 ± 0.07） kPa per minute up to maximum heart rate achieved. Then mean blood pressure decreased with （0.85 ±0.2 ） kPa per minute. Finally, there were 10 rabbits twitched to corneal reflex disappearance, muscle relaxation, convulsion and death, whose blood pressure and heart rate vanished. The total amounts of blood withdrawal was （ 55.3 ± 13.5 ） mL. Conclusions The Bezold -Jarisch reflex induced by experimental hemorrhage in animals mimics human VVS and is suitable model to study human VVS.