脂多糖诱导小鼠急性肺损伤与脂钙蛋白2表达

The correlation between acute lung injury and the expression of lipocalin 2 in mice challenged by lipopolysaccharide

目的观察不同剂量的脂多糖（LPS）造成的小鼠肺炎性病理损伤以及血清、肺组织中脂钙蛋白2（LCN2）和某些相关炎症细胞因子的表达水平，探讨LCN2作为急性肺损伤（Au）候选标志物的潜在价值。方法予C57BL／6小鼠不同剂量LPS腹腔内注射，10mg／kg、20mg／kg、30mg／kg各为一组，对照组仅注射同容量生理盐水，观察24h后留取肺组织和血清，ELISA和Westernblot测定IL-1B、IL-17A、LCN2，实时PCR相对定量肺组织中LCN2mRNA，HE染色观察肺病理改变。结果与对照组比较，LPS20mg／kg组和LPS30mg／kg组血清IL-6、LCN2及肺组织IL-1B、IL-17A、LCN2蛋白质浓度显著增高（P〈0．05）；与LPS10mg／kg组比较，LPS30mg／kg组血清IL-6、LCN2及肺组织IL-18、LCN2蛋白质浓度显著增高（P〈0．05）。各组LCN2mRNA浓度呈LPS剂量依赖性增高（P〈0．05）。LPS注射组表现出不同程度的肺组织炎性渗出和血管扩张充血，LPS20mg／kg组和LPS30mg／kg组较对照组以及LPS30mg／kg组较LPS10mg／kg组的病理评分显著增高（P〈0．05）。结论LPS剂量依赖性地引起肺组织LCN2表达水平增加．并与肺组织炎性病理损伤程度有一定程度关联。

Objective To explore the potential value of lipocalin 2 （LCN2） as a candidate biomarker of acute lung injury. Methods C57BL/6 mice injected intraperitoneally （ i. p. ） with lipopolysaecharide （LPS） were divided into three groups according to LPS dosage （10 mg/kg, 20 mg/ kg, 30 mg/kg） （n =8）. Mice in the control group （n =8） received i.p. equal volume of saline. 24 hours later, lung and blood were collected, and ELISA and Western blot were used to detect the protein levels of IL - 113, IL - 17A, LCN2, real time PCR to determine transcription levels of LCN2 in lung tissue. Histological alterations were examined by one pathologist in blind manner. Results The protein levels of IL - 6 and LCN2 in serum as well as IL - 17A, IL - 113, and LCN2 in lung in two groups （LPS, 20 mg/kg ＆ 30 mg/kg） were significantly higher than their counterparts in the control group （ P 〈 0. 05 ）. The protein levels of IL - 6 and LCN2 in serum as well as IL - 113 and LCN2 in lung were significantly higher compared to LPS 10 mg/kg group （P 〈 0.05 ）. Meanwhile, LPS injection increased pulmonary LCN2 mRNA levels dose -dependently. Most LPS challenged mice showed distinct inflammatory infiltration in lung while little histological changes occurred in the controls. The intergroup differences of pathological score of LPS 20 mg/kg group versus the control group, 30 mg/kg group versus the control group, and 10 mg/kg group versus 30 mg/kg group demonstrated statistical significance. Conclusion LPS dose -dependently increased LCN2 expression in lung, which has some kind of proportional relationship with lung pathological alteration in septic mice.