不同体外循环温度下离体中性粒细胞的激活

The effect of temperature on the neutrophil activation in the cardiopulmonary bypass

目的研究不同的体外循环温度下离体中性粒细胞激活程度的变化。方法抽取60名健康志愿者血样，提取中性粒细胞，随机数字法分为5组，每组12名，分别采用不同体外循环温度：常温、微温、中低温、深低温、复温过热。利用聚合酶链式反应仪建立温度对中性粒细胞刺激的体外模型。每组内设定6个时间点，分别为基线值（．1U）、复温起点（T1）、复温后0．5h（T2）、复温后1h（T3）、复温后1．5h（T4）和复温后2h（T5）。测定每个时间点的膜结合性弹性蛋白酶（membrane—boundelastase，MBE）值，作为中性粒细胞激活的程度。统计学处理采用SPSS13．0软件，组内比较采用重复测量方差分析，组间比较采用Bonfeoni法。结果MBE值的组内比较：常温和微温组随时间延长逐渐升高，均高于基线值（P〈0．01）；中低温、深低温及复温过热组在T1和T2时间点均低于基线值（P〈0．01），从T3时间点开始上升，复温过热组增长速度较中低温和深低温组快。MBE值的同时间点组间比较：T1、T2和T3时间点，常温组〉微温组〉其余各组（P〈0．05）；T4和T5时间点常温组与微温组之间差异无统计学意义，均高于其余各组（P〈0．05）；中低温、深低温和复温过热组之间比较随时间点不同而异：T1、他和T5时间点差异无统计学意义（P〉0．05），T3时间点复温过热组高于中低温组和深低温组（P〈0．05），T4时间点中低温和复温过热组高于深低温组（P〈0．05）。结论体外循环的温度变化可激活中性粒细胞、释放MBE，其中常温和微温促进、中低温和深低温则抑制这一过程。经过低温对中性粒细胞激活的抑制，MBE值复温过热时恢复最快，中低温次之，深低温最慢。

Objective Neutrophils, as important participants in the inflammatory response, contribute virtually to the tissue and organ damage in the cardiopulmonary bypass （CPB） We tried to investigate the contributing factors and mechanism for neutropbil activation in CPB at various temperature in vitro. Methods Neutrophils isolated from the blood of 60 healthy volunteers were divided into 5 temperature groups normothermia, tepid temperature, moderate hypotbermia, deep hypothermia and rewarming hypertbermia groups. An in vitro model was established with a polymerase chain reaction thermoeyeler for evalu- ating neutrophil activation Six time points were set in each group： TO standing for baseline, T1 for starting rewarming, T2 for 0.5, T3 for 1, T4 ： for 1.5 and T5 for 2 hours after rewarming. Membrane-bound elastase （MBE） activity, as an index for neutrophil activation, was measured every 0.5 hours throughout the experiment. SPSS 13.0 was used for intra-group and intergroup comparisons. Analysis of variance （ repeat measure ANOVA） was used for comparisons among different time points. Bonferroni method would be used for pairwise comparison if a significant difference was observed between two effects with analysis of variance. Results For inter-group comparisons of MBE at different time points ： at T1 ,T2 and T3 time points, the activity of MBE in the normothermia group was higher than that in the tepid temperature group and far more higher than in the other groups （ P 〈 0.05 ） . There was no significant difference in the activity of MBE between normothermia and tepid temperature groups but the values of MBE in the two groups were higher than those in the other groups at T4 and T5 time points （ P 〈 0.05 ） . The comparisons among rewarming hyperthermia group, moderate hypothermia group and deep hypothermia group varied with time points ： at T1, T2 and T5 time points, there were no significant difference （ P 〉 0.05 ） ; however, at T3 time point, the activity of MBE in the rewarming hyperthetania group was higher than that in the moderate hypothermia and deep hypothermia groups （ P 〈0.05 ） ; at T4 time point, the activity of MBE in the moderate hypothermia group and rewarming byperthermia group was higher than that in the deep hypothermia group（P 〈 0.05 ） . Conclusion Neutrophil activation changed dynamically with the temperature in CPB. Normothermia and tepid temperature promoted while moderate hypothermia and deep hypothermia inhibited the activation Recovery for neutrophil activation was faster in the rewarming hyperthermia than in the moderate hypothermia, and the recovery in profound hypothermia was the slowest after a hypothermic inhibition.