Pulmonary Fibroproliferation Occurred Early In The Acute Lung Injury Rats And The Protective Effect Of Interferon Gamma

Objective The purpose of this study was to investigate pulmonary fibroproliferation occurred early in the acute lung injury (ALI) rats by injecting oleic acid into tail vein and the mechanism of pulmonary fibroproliferation, explore the protective effect of interferon gamma (IFN-γ) on pulmonary fibroproliferation in OA induced ALI in rats and its mechanism, and provide a new clinical method to diagnose and treat ALI., as well as provide a new study way for ALI.Methods The model of ALI in rats was reproduced by injecting oleic acid into the tail vein. One hundred and eight adult Sprague-Dawley rats(weight 290—310g, regardless of sex) were randomly divided into three groups: normal control group treated by injecting saline (NS group, n=36) ; ALI group induced by injecting oleic acid (0.12ml/kg ) (OA group, n=36) ; therapy group treated by injecting IFN-γ(I&O group, n=36). Each group was separated into three subgroups at three different time points: 1 day, 3 day and 7 day. In the OA group and the I&O group ,OA was injected into tail vein, and saline was injected in the NS group. In the I&O group , after the injection of OA, the IFN-γ(150000IU/kg/day ) were injected intraperitoneally immediately, and 150000IU/kg/day in the 3 and the 7 day subgroups, while saline was injected at the same time in the OA group and the NS group. Each rat was exsanguinated and sacrificed at the corresponding time point (1, 3 and 7 day) . Arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), power of hydrogen (pH) and plasma PIIINP concentration level were evaluated. The left lung was used to investigate histopathology and calculate wet / dry weight ratio(W/D), whereas the right lung was lavaged and determined the total proteins(TP),total phospholipids (TPL), phosphatidylcholine (PC) and PIIINP concentration in the bronchoalveolar lavage fluid(BALF).Results 1. In the OA group, compared with the NS group at the same time point, there showed obvious pathological manifestations of ALI, such as hyperemia , edema , hemorrhage. TPL and PC/TPL in the BALF were significantly and progressively decreased (P<0.01), whereas TP ,W/D and PIIINP concentration were progressively increased (P<0.01). There were significant difference in PaO2, PaCO2, pH between...