摘要目的 探讨核仁素在脓毒症小鼠心肌损伤中的表达及其作用.方法 采用盲肠结扎穿孔术(CLP)制备脓毒症小鼠模型.实验动物随机分为4组:野生鼠C57BL/6+假手术组(WT+Sham)、WT鼠+脓毒症组(WT+CLP)、心肌特异性过表达转基因鼠(TG鼠)+假手术组(TG+Sham)及TG鼠+脓毒症组(TG+CLP).Western blotting观察脓毒症术后0、12、24、48 h核仁素的表达情况;术后24 h检测血流动力学指标、血清心肌损伤指标肌酸激酶同工酶(CK-MB)和肌钙蛋白(cTnI)水平、心肌细胞中活性氧(ROS)及心肌组织中脂质过氧化产物丙二醛(MDA)水平的变化情况.两组间数据比较采用t检验.结果 与WT+Sham组相比,WT+CLP组心肌组织中核仁素表达明显升高(2.57±0.34比1.00±0.15,t=7.468,P＜0.01);与WT+Sham组相比,WT+CLP组7d生存率显著下降(33.3％比100％,x2=13.375,P＜0.01);左心室等容收缩压力上升的最大速率(+dp/dtmax)显著下降(t=4.993,P＜0.01,n=10),血清CK-MB、cTnⅠ水平明显升高(t=5.031、4.335,均P＜0.01),心肌组织中ROS和MDA水平亦显著升高(t=3.365、2.375,均P＜0.05).与WT+CLP组相比,TG+ CLP组小鼠7d存活率明显升高(60.0％比33.3％,x2=8.227,P=0.004),+dp/dtmax明显改善(t=2.337,P=0.019),血清CK-MB、cTnⅠ水平及心肌组织中ROS、MDA水平均明显下降(t=2.127、3.347、2.115、2.224,均P＜0.05).结论 小鼠脓毒症可诱导心肌组织中核仁素表达上调,心肌特异性过表达核仁素可减轻脓毒症小鼠中氧化应激所致的心肌损伤和心功能障碍,降低其死亡率.

abstractsObjective To explore the expression and roles of nucleolin in cardiac injury in septic mice.Methods C57BL/6 mice (WT mice) and myocardium-specific expression of nucleolin transgenic mice (TG mice) were randomly divided into sham group (n=10,sham-operated) and sepsis group (n=15,animal model).Cecal ligation and puncture (CLP) was adopted to produce animal models of sepsis.The expression of nucleolin was detected by Western blotting analysis at 0,12,24,48 hours after the operation.The 7-day survival rate,haemodynamic measurement,levels of isoenzyme of creatinekinase-MB (CK-MB) and cardiac troponin Ⅰ (cTnⅠ) in serum and levels of reactive oxygen species (ROS) and malondlaldehyde (MDA) in myocardium were evaluated 24 hours after the operation.The data were compared between groups with t test.Results The expression of nucleolin in myocardium up-regulated significantly in WT+CLP group when compared with that in the WT+Sham group(2.57±0.34 vs 1.00±0.15,t=7.468,P＜0.01).Compared with those in the WT+Sham group,the survival rate decreased (33.3％ vs 100％,x5=13.375,P＜0.01),maximal rate of pressure development (+dp/dtmax) declined (t=4.993,P＜0.01),but the serum levels of CK-MB and cTnI and the levels of ROS and MDA in myocardium increased in the WT+CLP group(t=5.031,4.335,3.365,2.375,all P＜0.05).Compared with that in WT+CLP group,the 7-day survival rate of mice increased in TG+CLP group (60.0％ vs 33.3％,x2=8.227,P=0.004),and the cardiac function improved (t=2.337,P=0.019),but the serum levels of CK-MB and cTnⅠ and the levels of ROS and MDA in myocardium in TG + CLP group reduced significantly (t=2.127,3.347,2.115,2.224,均P＜0.05).Conclusion The expression of nucleolin is up-regulated in the myocardium of septic mice,and the overexpression of nucleolin can inhibit oxidative stress injury,attenuate the cardiac injury and dysfunction,and reduce mortality in septic mice.