丙泊酚对脓毒症心肌收缩功能障碍的改善作用及机制

Effect and mechanism of propofol on myocardial contractile dysfunction in sepsis

目的探讨丙泊酚对脓毒症心肌收缩功能障碍的改善作用及其机制。方法采用盲肠结扎穿孔术(cecal ligation and puncture,CLP)建立大鼠脓毒症模型,24只成年SD大鼠按照随机数字表法分为3组,①假手术组;②脓毒症组:造模12 h后取材;③丙泊酚治疗组:造模后腹腔注射丙泊酚(Propofol,10 mg/kg),12 h后再次注射丙泊酚,3 h后取材。利用细胞微张力仪,测量急性分离心肌细胞的肌节长度和细胞内钙离子荧光强度的变化情况。急性分离丙泊酚组心肌细胞,分别加入肌醇1,4,5-三磷酸受体(inositol-1,4,5-triphosphate receptor,IP_(3)R)抑制剂[2-aminoethyl diphenylborinate(2-APB)]、肌浆网Ca^(2+)-ATP酶(sarco/endoplasmic reticulum Ca^(2+)-ATPase,SERCA)抑制剂[2,5-di-t-butyl-1,4-benzohydroquinone(BHQ)]、雷诺丁受体(Ryanodine receptors,RyRs)抑制剂Azumolene及大电导钙激活钾通道(large conductance Ca^(2+)-activated K^(+)channels,BKCa)抑制剂Paxiline后,检测心肌细胞的肌节长度和细胞内钙离子荧光强度的变化情况。结果与假手术组相比,脓毒症组心肌细胞收缩功能和钙瞬变幅度显著下降;丙泊酚治疗可显著恢复脓毒症心肌细胞的收缩功能和钙释放能力,最大收缩幅度恢复27.6%(P<0.05),最大钙瞬变幅度恢复41.2%(P<0.05),2-APB和BHQ明显抑制丙泊酚对心肌细胞的收缩功能的改善作用,其抑制率分别为62.61%(P<0.05)和42.15%(P<0.05),但Azumolene对收缩功能无显著影响。2-APB、BHQ和Azumolene对丙泊酚改善钙瞬变都有不同程度的抑制作用,其中Azumolene对钙瞬变抑制效果最小,其抑制率为46.94%(P<0.05),而2-APB和BHQ的抑制率分别为65.28%(P<0.05)、65.33%(P<0.05)。Paxiline对丙泊酚改善心肌细胞收缩功能和钙瞬变无显著影响。结论丙泊酚可改善脓毒症心肌细胞的收缩功能,其机制可能与其通过IP_(3)R和SERCA调节钙离子浓度相关。

Objective To investigate the effect and mechanism of propofol on myocardial systolic dysfunction in sepsis.MethodsCecal ligation and puncture(CLP)was used to induce a septic rat model.Twenty-four adult SD rats were randomly divided into sham group,sepsis group(the samples were taken 12 h after CLP modeling)and propofol group(10 mg/kg propofol was injected intraperitoneally in 0 and 12 h after CLP modeling,and the samples were taken 3 h after the second injection of propofol).Sarcomere length and intracellular calcium fluorescence intensity of myocardial cells were measured by cell microtensiometer.Further,acute isolated cardiomyocytes from the propofol group were incubated with inositol 1,4,5-triphosphate receptor(IP_(3)R)inhibitor 2-aminoethyl diphenylborinate(2-APB),sarco/endoplasmic reticulum Ca^(2+)-ATPase(SERCA)inhibitor 2,5-di-t-butyl-1,4-benzohydroquinone(BHQ),ryanodine receptor(RyRs)inhibitor azumolene,and large conductance calcium-activated potassium channel(BKCa)inhibitor paxiline,respectively.Then sarcomere length and intracellular calcium fluorescence intensity of myocardial cells were measured again.Results Compared with the sham group,the contractile function and calcium transient amplitude of myocardial cells were significantly decreased in the sepsis group,while propofol treatment obviously restored the contractile function and calcium release ability of myocardial cells in sepsis,with a maximum contractile amplitude restoration of 27.6%(P<0.05)and a maximum calcium transient amplitude restoration of 41.2%(P<0.05).However,2-APB and BHQ notably suppressed the improvement of contractile function of cardiomyocytes induced by propofol,with an inhibitory rate of 62.61%(P<0.05)and 42.15%(P<0.05),respectively.However,azumolene had no significant effect on contractile function.Further studies showed that azumolene,2-APB and BHQ had inhibitory effects on calcium transients with different extent.Among the 3 inhibitors,azumolene showed the mildest inhibitory effect,with a rate of 46.94%(P<0.05),and the rate was 65.28%(P<0.05)and 65.33%(P<0.05),respectively for 2-APB and BHQ.Paxiline had no statistical effect on propofol improving myocardial contractile function and calcium transients.Conclusion Propofol improves the contractile function of myocardial cells in sepsis,which may be related to the regulation of calcium concentration through IP_(3)R and SERCA.