A study of effect of N-Acetylcysteine on expression of lung tissue transforming growth factor-β1 in rats with acute lung injury

Objective To observe the effect of N-acetylcysteine(NAC) on the expression of lung tissue transforming growth factor-β1(TGF-β1) in rats with acute lung injury(ALI) induced by lipopolysaccharide(LPS).Methods Twenty-four SD rats were randomly divided into four groups: normal control group,ALI model group(ALI group),dexamethasone pretreatment group and NAC pretreatment group,6 rats being in each group.The model of ALI in rats was reproduced by intravenous injection of LPS in the dose of 5 mg/kg.Twenty-four hours after the model was established,the rats were killed.The lung tissue in the left lobe was adopted for the pathological examination and TGF-β1 immunohistochemical staining.Results The gray scale value of TGF-β1 in ALI group was decreased markedly compared with that in the normal control group(155.42±3.58 vs.190.81±6.28,P0.01),it suggested that the expression of TGFβ1 was significantly increased.Compared with the ALI group,the lung pathological manifestations(phlegmatic cell infiltration,exudation,hemorrhage) were ameliorated in NAC group,and the gray scale value of TGF-β1 in the lung was increased significantly in NAC and dexamethasone pretreatment groups(187.30±20.92 and 193.99±17.80 vs.155.42±3.58,both P0.01),the result suggested that the expression of TGF-β1 was significantly decreased,and no significant difference was found among NAC and dexamethasone pretreatment groups and normal control group(all P0.05).Conclusion NAC can inhibit the expression of lung tissue TGF-β1 in the early phase of ALI,and the lung pathological manifestations also display obvious pathological improvement,therefore NAC has protective effect at the early phase of ALI.