Expressions and evaluation of CXCL1 and CXCL2 in lung tissue of ARDS mice

Objective To investigate the expression changes of CXCL1 and CXCL2 in the lung tissue of acute respiratory distress syndrome (ARDS) mice, and to explore the roles of CXCL1 and CXCL2 in ARDS mice. Methods 42 male C57BL/6 mice were randomly divided into normal control group, lipopolysaccharide (LPS) tracheal instillation for 15 minutes, 30 minutes, six hours, 24 hours, three days, and seven days groups, with six mice in each group.HE staining was used to observe the morphological changes of lung tissue, and the lung injury score was calculated.The mRNA expression levels of CXCL1 and CXCL2 in lung tissues were detected by RT-PCR, and the levels of CXCL1 and CXCL2 in bronchoalveolar lavage fluid (BALF) were detected by enzyme linked immunosorbent assay.The number of neutrophils in BALF was calculated. Results Compared with the normal control group, the alveolar and interstitial tissue structure of ARDS mice were disappeared and filled with inflammatory cells.The lung injury score of ARDS mice was increased and reached the highest level at the 3rd day.The levels of CXCL1 and CXCL2 mRNA in lung tissues of ARDS mice were significantly increased, and respectively reached a peak at 30 minutes and six hours after LPS instillation.Simultaneously, the levels of CXCL1 and CXCL2 in BALF of ARDS mice were significantly increased, and the change trends were consistent with mRNA levels in lung tissues.Besides, the number of neutrophils in the BALF of ARDS mice was significantly increased. Conclusions The number of neutrophils and the expressions of CXCL1 and CXCL2 in the LPS-induced ARDS mice all show a similar hump-like rise with time, which indicates that neutrophil chemotactic factors play an important role in the formation and development of ARDS inflammatory injury. Key words: Acute respiratory distress syndrome; Chemokine CXCL1; Chemokine CXCL2; Neutrophil infiltration