Effect of N-acetylcysteine on the expression of transforming growth factorβ_1 in pulmonary fibrosis rats

Objective To evaluate effect of N-acetylcysteinein on pulmonary interstitial fibrosis,we investigated pathological change of lung and genetic and protein expression of TGF-β1 in bleomycin-induced pulmonary interstitial fibrosis in rats which were treated with N-acetylcysteinein.Methods Thirty female Wistar rats were randomly divided into three groups:a bleomycin-induced-fibrosis group(Group B) which was administered to bleomycin(5 mg.kg-1) intratracheally,a bleomycin-induced-fibrosis group treated with N-acetylcysteine(3 mmol.kg-1.day-1)(Group N) and the control group(Group C) which was treated with saline.Group N were fed with N-acetylcysteine every day from one week before the single intratracheal instillation of blemycin upto the day being executed on the 7 th and 14 th day.We observed their pulmonary pathological change under HE staining and the change of mRNA and protein expression of TGF-β1 by immunnohistochemical method in the lung.Reverse transcription polymerase chain reaction(RT-PCR) was used to detect the expression of TGF-β1mRNA in the lung.Results The most serious pulmonary fibrosis was found in Group B while Group C shows no obvious alveolitis and lung fibrosis.Attenuation of alveolitis and lung fibrosis after treatment with NAC was observed in pathological section(P0.05).Expression of TGF-β1 protein and TGF-β1mRNA in group B were higher than group C at 7th and 14 th day(P0.05).Compared with group B,the level of expression of TGF-β1 protein and TGF-β1mRNA in group N decreased at 7th and 14th day after treatment with NAC.Conclusion N-acetylcysteine can inhibit alveolitis and fibrosis.It maybe plays a protective role by inhibition of the production of TGF-β1 protein and TGF-β1mRNA.N-acetylcysteine has notable protective effects in bleomycin-induced pulmonary interstitial fibrosis of rats.