Effects of N-acetyicysteine on dynamic expression of nuclearfactor-kappaB in bronchoalveolar lavage cells of mice with pulmonary fibrosis

Abstract

Objective To investigate the effects of N-acetylcysteine （NAC） on dynamic expression of nuclear factor-KB （NF-KB） in mice with bleomycin （BLM）-induced interstitial pulmonary fibrosis. Meth- otis A total of 75 C57BL/6 naice were randomly allocated into three groups. The mice in BLM group （n = 25） and control group （n = 25） received resPectively intratracheal instillation of BLM and saline, and those in NAC group were given NAC once a day via the esophagus 5 days before BLM treatment in 25 mice until sampling. On the day 1, 3, 7, 14, and 28, the left lung tissue was collected for hematoxylin and eosin （HE） and Masson staining, and bronchoalveolar lavage performed 3 times in the right lungs and bronchoalve- olar lavage cells to detect the NF-KB p65 expression. Results On the day 7, 14 and 28, as compared with BLM group, excessive lung solidation and collagen sediment in NAC group was significantly reduced. On the day 1 after the intratracheal instillation of BLM, the positive expression rate of p65 protein and mRNA in BLM group was 43.45± 3. 60 and 42. 24 ± 2. 59, and that in NAC group was 21.43± 2. 86 and 25.21 ± 3. 03, respectively. The p65 protein expression in the nuclei and p65 mRNA expression in the plasma in the bronehoalveolar lavage cells were significantly higher, and decreased with the prolongation of the disease course. There was significant difference in level of NF-κβ p65 expression in the bronchoalveolar lavage cells among 3 groups, and level of NF-κβ p65 expression in NAC group was lower than that in BLM group （P 〈 0. 05 ）. Conclusion In the process of BLM-indueed interstitial pulmonary fibrosis, the expression of NF-KB in bronehoalveolar lavage cells increases obviously. NAC may alleviate the extent of BLM-induced pulmonary fibrosis through inhibiting the transcription of NF-KB p65 mRNA and reducing the expression of NF-KB p65 protein. Key words: N-acetylcysteine; Bleomyein; Nuclear faetor-κβ ; Interstitial pulmonary fibrosis