Protective Effect Of Azithromycin On Acute Lung Injury Induced By Oleic Acid In Rat

Objective The purpose of this study was to reproduce the model of acute lung injury (ALI) in rats by injecting oleic acid (OA) into the vein, and investigate the alterations of tumour necrosis factor-α(TNF-α),interferon Gamma (IFN-γ), interleukin-4 (IL-4) after ALI induced by OA, and investigate the possible mechanisms of protective effects of azithromycin in OA induced ALI in rats.Methods OA was used to reproduce the model of ALI in rats. 90 adult Sprague-Dawley rats were randomly divided into three groups: normal control group treated by saline injection (NC group),ALI group induced by oleic acid injection (OA group),therapy group treated by oral azithromycin (AZI group).Arterial oxygen tension (PaO2), arterial carbon dioxide tension (PaCO2), power of hydrogen (pH) and plasma interleukin-4 level were assayed after the animals were exsanguinated and sacrificed at 1, 3 and 7 days later. The left lung was used to calculate wet / dry weight ratio(W/D),histopathology, whereas the right lung was lavaged and determined the total proteins(TP),TNF-α,IFN-γand IL-4 concentration in the bronchoalveolar lavage fluid(BALF), total cell counts and differential analysis in BALF were performed.Results In the OA group, W/D,TNF-α,TP and inflammatory cell counts in the BALF were significantly increased (P <0.01), whereas the ratio of IFN-γ/ IL-4,arterial oxygen tension (PaO2) were significantly decreased(P<0.01) as compared with NC group. Obvious pathological manifestations such as hyperemia,edema,hemorrhage,neutrophil infiltration were shown . In the AZI group, the change of lung pathology was significantly relieved, the ratio of IFN-γ/ IL-4,PaO2 were increased(P <0.05), W/D,TNF-αwere significantly decreased (P <0.05)as compared with OA group. The IL-4 concentrations in the BALF were positively correlated to those in the plasma in the OA and AZI group at the same time point (rOA1= 0.857;rOA3=0.841;...