Comparison of in vivo protective effect of N-acetyl-cysteine and dexamethasone in lipopolysaccharide-induced acute lung injury in rats

Objective To compare the protective effect of N-acetyl-cysteine(NAC) and dexamethasone(Dex) in acute lung injury (ALI),and to provide a better method in treating ALI.Methods Lipopolysaccharide (LPS,5 mg/kg) was used to reproduct the model of ALI in rats.Thirty-two adult SD rats were randomly divided into four groups and there were eight rats in each group:control group(NS group);ALI model group (LPS group);NAC pretreatment group (NL group) and Dex pretreatment group (DL group).In the latter two groups,NAC(200 mg/kg) and Dex(70 mg/kg) were injected intraperitoneally at an hour before LPS was given intravenously.Four hours after LPS was given,the rats were killed and the pathological manifestation of rats' lung was observed,the lung index was calculated,the intension of nuclear factor-κB(NF-κB) expression of rat's lung was analyzed by the method of immunohistochemistry,and also the concentration of nitric oxide (NO) and malonyldialdehyde(MDA) in serum was detected.Result Compared with the LPS group,the pathological manifestation of rats' lung was ameliorated, and the evaluation of lung index,the expression of NF-κB in rat's lung,the concentration of NO and MDA in serum were decreased significantly in NL group and DL group( P 0 01), and there were no significance in NL group and DL group or NS group( P 0 05).Conclusion Each of NAC and Dex could protect ALI and there was different effect between them.Considered the side-effects of Dex,it was promising to use NAC in the treatment of ALI.