维生素C预处理对脓毒症小鼠肺组织miR126a-5p、miR155-5p表达的影响

Effect of vitamin C on the expression of miR126a-5p and miR155-5p in the lung tissue of sepsis mice

目的:观察维生素C(vitamin C,Vit C)干预后脓毒症小鼠肺组织炎症表达情况及miR126a-5p和miR155-5p含量的变化,分析Vit C对脓毒症急性肺损伤的潜在保护机制。方法:选择4~6周雄性小鼠18只随机分为假手术组(对照组、CON组)、脓毒症+NS组(SEP组)、脓毒症组+Vit C干预组(SEP+IR组),予Vit C 1000 mg/kg术前连续3 d尾静脉进行注射,采用盲肠穿刺结扎制作模型,术后12 h检测肺组织的湿重/干重(W/D);用HE染色的方法观察肺脏病理形态,测量肺泡的直径;用RT-qPCR检测miR126a-5p、miR155-5p的变化,Western blotting检测Caspase 1及Caspase-3的蛋白表达量,ELISA法检测白细胞介素(IL)-6和肿瘤坏死因子(TNF)-α表达。结果:与CON组相比,SEP组中肺的W/D增加,肺泡孔径明显减小;SEP组中的miR126a-5p和miR155-5p以及蛋白Caspase 1和Caspase 3表达量升高;同时可进一步促进炎症因子IL-6和TNF-α增加(P<0.05)。与SEP组相比,SEP+IR肺组织的W/D减低,肺泡孔径增大,miR126a-5p和miR155-5p以及蛋白Caspase 1和Caspase 3表达量降低,同时可进一步抑制炎症因子IL-6和TNF-α的增加(P<0.05)。结论:Vit C具有减轻肺水肿和稳定肺泡体积的作用,可能与miR126a-5p和miR155-5p诱导的Caspase 1、Caspase 3表达降低有关。

Objective:To observe the inflammatory cytokines expression of lung tissue and the changes of miR126a-5p and miR155-5p in septic mice after vitamin C(Vit C)intervention,and to analyze the potential protective mechanism of Vit C in the acute lung injury in sepsis.Methods:A total of 18 male mice(4 to 6 weeks)were selected and randomly divided into the control group(CON),sepsis+NS group(SEP)and sepsis+Vit C intervention group(SEP+IR),before the injection of Vit C 1000 mg/kg by tail vein for three consecutive days in the cecum puncture ligation model.Wet weight/dry weight(W/D)of lung tissue was measured 12 h after operation.HE staining was used to observe the pathological appearance of lung and the diameter of alveoli was measured.The changes of miR126a-5p and miR155-5p were detected by RT-qPCR,the protein expressions of Caspase 1 and Caspase 3 were detected by Western blot,and the expressions of IL-6 and TNF-αwere detected by ELISA.Results:Compared with CON group,the W/D of lung in SEP group was increased and the alveolar aperture was decreased significantly in SEP group.The expressions of miR126a-5p,miR155-5p,Caspase 1 and Caspase 3 were increased in SEP group.Meanwhile,the inflammatory cytokines IL-6 and TNF-αwere further increased(P<0.05).Compared with SEP group,SEP+IR group had lower W/D,higher alveolar pore size,lower expression in miR126a-5p,miR155-5p,Caspase 1 and Caspase 3.Vit C further inhibited the increase of inflammatory cytokines IL-6 and TNF-α(P<0.05).Conclusions:Vit C can reduce pulmonary edema and stabilize alveolar volume,which may be related to the decreased expressions of Caspase 1 and Caspase 3 induced by miR126a-5p and miR155-5p.