急性低氧应激对麻醉大鼠心脏舒缩功能的影响

Effects of acute hypoxic stress on cardiac systolic and diastolic functions in anesthetized rats

目的探讨急性低氧应激对麻醉大鼠左、右心室舒缩功能的影响。方法监测大鼠(n=7)在常氧(西宁,海拔2260m,氧百分含量为20.9%)和急性低氧(氧百分含量为15%)通气的状态下,心率(heart rate,HR)、左心室收缩压(Left ventricular systolic blood pressure,LVSP)、右心室收缩压(Right ventricular systolic blood pressure,RVSP)和左右心室内压最大上升及下降速率(±d P/dt_(max))等的血流动力学指标变化。同时,比较低氧通气5 min前后的动脉血气,探讨急性低氧应激对麻醉大鼠心脏功能的影响。结果与常氧通气相比,急性低氧通气下LVSP降低、RVSP升高,右心室±d P/dt_(max)升高,左心室±d P/dt_(max)明显降低,均具有统计学差异(P<0.05)。此外,低氧通气5 min后大鼠动脉血PaO_2降低,具有统计学差异(P<0.05)。结论急性低氧应激可降低左心室的舒、缩能力,而右心室的舒、缩在急性低氧应激时则表现出一定程度的代偿性增强,但低氧应激对左心室的舒缩能力影响更大。

Objective To explore the effect of acute hypoxic stress on the left and right ventricular systolic and diastolic functions in anesthetized rats.Methods Rats （n = 7）were treated with normoxia（ 20.9% of the oxygen con- tent） and hypoxia（ 15% of the oxygen content）respectively at the altitude of 2260 m （Xining, China）.The heart rate （HR）, the maximum rate of left and right ventricular pressure（ ±dP/dtmmax ）, the left ventricular systolic blood pres- sure （ LVSP）, the right ventricular systolic blood pressure （RVSP） were monitored, and the arterial blood gas of nor- moxia and hypoxia within 5 minutes have been compared to explore the effect of acute hypoxia on cardiac function in anesthetized rats. Results Compared with nomorxia, the LVSP and ：±dP/dtmax of left ventricular decreased, the RVSP and ±dP/dtmax of right ventricular increased obviously in hypoxia（ P〈0.05 ）. In addition, the PaO2 had de- creased after 5 minutes of hypoxia（ P〈0.05 ）.Conclusion Acute hypoxic stress can decrease the left ventricular sys- tolic and diastolic functions.But the change of right ventricular systolic and diastolic functions are characterized by acertain degree of compensatory enhancement.And the left ventricular systolic and diastolic functions are more affect- ed than fight ventricular.