Instilled air promotes lipopolysaccharide-induced acute lung injury

Optimization of intratracheal instillation is necessary to establish an ideal animal model of acute lung injury (ALI) in order to further reveal the cellular and molecular pathogenesis of ALI. It is possible that instilling air from a prefilled syringe may promote the delivery of reagents into the alveolar spaces, resulting in different pulmonary responses. In the present study, the influence of instilling air by trans-tracheal intratracheal instillation in a lipopolysaccharide (LPS)-induced mouse model of ALI was investigated. The bronchoalveolar lavage (BAL) fluid biochemical index, BAL fluid differential cell counts, lung wet/dry weight ratio, lung histology and BAL fluid interleukin-8 (IL-8) levels were assessed 24 h subsequent to intratracheal instillation. Instilled air promoted LPS-induced ALI, as indicated by the severity of acute pulmonary inflammation and increased IL-8 release. In conclusion, this study indicates that instilled air may be used to improve the intratracheal instillation procedure and to establish a more reliable animal model of ALI.