[Changes and role evaluation of TNF-α and IL-1β in lung tissues of ARDS mice]

Objective To study the expression levels of TNF-α and IL-1β in the lung tissues of acute respiratory distress syndrome (ARDS) mice and their relationships with the severity of lung injury in the mice. Methods A mouse model of ARDS was induced by lipopolysaccharide (LPS). The morphological changes of lung tissue was observed by HE staining, and the lung injury score was calculated. Quantitative real-time PCR was employed to detect the mRNA expression levels of TNF-α and IL-1β in lung tissues and ELISA was performed to test the protein levels of TNF-α and IL-1β in bronchoalveolar lavage fluid (BALF). Results Compared with the control group, the alveolar and interstitial tissue structure of ARDS model mice was impaired and filled with inflammatory cells. The lung injury score of ARDS model mice reached the peak at the third day. The mRNA levels of TNF-α and IL-1β in lung tissues of ARDS mice significantly increased, and respectively peaked at 30 minutes and 6 hours after LPS instillation. Simultaneously, the levels of TNF-α and IL-1β in BALF of ARDS mice significantly increased, and the tendency was consistent with mRNA levels in lung tissues. Conclusion LPS-induced lung injury and the expression levels of TNF-α and IL-1β in ARDS mice showed a similar "hump-like" increase over time. The high values of inflammatory mediators appeared before the peak of lung injury, which indicated that these inflammatory cytokines played an important role in the development of ARDS-caused inflammatory injury.