社区获得性肺炎并脓毒症患者Caspase-12基因多态性及表达的研究

Research of Polymorphism and expression of Caspase-12 in patients with sepsis diagnosed as community-acquired pneumonia

目的:分析由社区获得性肺炎导致的脓毒症患者外周血Caspase-12基因多态性,及Caspase-12基因和Caspase-12前体蛋白的表达,了解上述指标在脓毒症发病中的作用。方法:选取2016年2月至2018年5月于内蒙古医科大学第三附属医院呼吸与危重症医学科确诊的社区获得性肺炎并脓毒症患者34例为脓毒症组,22名健康者为对照组。以Caspase-12的T125C特异碱基为引物,对外周血基因组DNA进行扩增、测序及多态性鉴定。RT-PCR法检测Caspase-12 mRNA表达,蛋白质印迹法检测Caspase-12前体蛋白表达。结果:脓毒症组Caspase-12的T125C基因位点未检出多态性。脓毒症组血Caspase-12 mRNA及Caspase-12前体蛋白表达明显高于对照组(t=6.44、4.62,P<0.001)。入院第一天Caspase-12 mRNA与Caspase-12前体蛋白表达水平显著正相关(r=0.70,P<0.0001)。Caspase-12 mRNA和Caspase-12前体蛋白表达的曲线下的面积分别为0.901和0.719。将Caspase-12 mRNA和Caspase-12前体蛋白的截断点分别设为0.907和0.578,脓毒症诊断的敏感度和特异度分别为78.0%、65.2%和89.9%、70.4%。结论:本研究未检测到Caspase-12 T125C基因多态性。社区获得性肺炎导致脓毒症患者Caspase-12 mRNA和Caspase-12前体蛋白表达显著升高,与脓毒症有明显相关性,且对脓毒症的预警具有一定价值。

Objective To observe the polymorphism of Caspase-12 and to detect the expression of Caspase-12 gene and precursor protein in peripheral blood of patients with sepsis caused by community acquired pneumonia.Methods There were 34 patients with sepsis diagnosed as community-acquired pneumonia admitted to the department of respiratory and critical care medicine of the third affiliated hospital of Inner Mongolia medical university and 22 healthy subjects were divided into the sepsis group and the control group.With the T125C specific base of Caspase-12 as the primer,the peripheral blood genomic DNA was amplified and sequenced for polymorphism identification.The expression of Caspase-12 mRNA and Caspase-12 precursor protein was detect by RT-PCR and Western blot.Results No T125C polymorphism of Caspase-12 was detected in the sepsis group.The expression of blood Caspase-12 mRNA and Caspase-12 precursor protein in the sepsis group was significantly higher than that in the control group(t=6.44,4.62,P<0.001).On the first day,the expression level of Caspase-12 mRNA was positively correlated with the expression of Caspase-12 precursor protein(r=0.70,P<0.0001).The AUCs of Caspase-12 mRNA expression and Caspase-12 precursor protein expression were 0.901 and 0.719.The sensitivity and specificity of diagnosing sepsis were 78.0%,65.2%and 89.9%,70.4%,respectively when setting the expression level of Caspase-12 mRNA and Caspase-12 precursor protein as 0.907 and 0.578.Conclusions No T125C polymorphism of Caspase-12 was detected in this study.The expressions of Caspase-12 mRNA and precursor protein in patients with sepsis diagnosed as community-acquired pneumonia were significantly increased and correlated with each other,which both show significant diagnostic value against sepsis.