治疗性低温对大鼠心肌细胞收缩功能的保护作用

Protective effect of therapeutic hypothermia on contractile function of myocardial cells in rats

目的:探讨温度对大鼠心肌细胞收缩功能的影响,并寻找可用于心肌保护的最佳温度。方法:用酶解法急性分离大鼠左室心肌细胞并复钙,采用可视化单细胞动缘探测系统检测并比较逐步升温(25~37℃)和恒温孵育(25、30、35℃)对大鼠心肌细胞收缩功能的影响,用收缩幅度的相对变化作为评价指标,明确能使心肌细胞产生最大且最稳定收缩的温度。结果:27~37℃逐步升温过程中,大鼠心肌细胞接受持续电刺激后稳定收缩的比例随温度的升高而下降。27~30℃逐步温度升高过程中,大鼠心肌细胞收缩幅度与25℃相比逐渐增大(P<0.05);31~37℃时,随着温度继续上升,心肌细胞出现不规律收缩、形态改变,甚至挛缩死亡,且收缩幅度与25℃比较,差异无统计学意义(P>0.05)。25℃、30℃、35℃固定恒温孵育后的心肌细胞收缩幅度两两比较,差异均有统计学意义(P<0.05),其中30℃孵育的细胞收缩幅度最大且稳定(P<0.05)。结论:温度变化影响大鼠心肌细胞的收缩功能,30℃时细胞收缩力强且稳定。

Objective:To study the effect of temperature on the contractile function of rat cardiomyocytes and to find the best temperature for myocardial protection.Methods:Rat left ventricular cardiomyocytes were separated by enzymolysis and supplemented with calcium.Visualized single-cell moving edge detection system was used to detect and compare the effects of gradual warming(25~37℃)and constant temperature incubation(25℃,30℃,35℃)on the systolic function of rat cardiomyocytes,and the relative change of contraction amplitude was used as an evaluation index.The temperature at which cardiomyocytes could contract at their maximum and most stable level was determined.Results:The proportion of stable contraction of rat cardiomyocytes after receiving continuous electrical stimulation decreased with the increase of temperature during the gradual warming from 27~37℃.From 27~30℃,the contraction amplitude of myocardial cells increased with the increase of temperature compared with 25℃(P<0.05).At 31~37℃,as the temperature continued to rise,cardiomyocytes would show irregular contraction,morphological changes,and even contracture death,and the contraction amplitude had no significant difference compared with 25℃(P>0.05).There was statistically significant difference in the contraction amplitude of cardiomyocytes after incubation at 25℃,30℃and 35℃(P<0.05),and the contraction amplitude of cells incubated at 30℃was the largest and stable(P<0.05).Conclusion:Temperature changes affect the contractile function of rat cardiomyocytes,and the contractile force is strong and stable at 30℃.