The changes of localization and expression of acetylated tubulin αin silicosis fibroblasts / 中国职业医学

ABSTRACT

OBJECTIVE: observe the changes of localization and expression of acetylated tubulin alpha( Ac-tubulin α) in fibroblasts of silicosis fibrosis. METHODS: i) A total of 22 autopsy case with coal workers' pneumoconiosis( CWP) was selected as CWP group( autopsy lesion lung tissue) and their adjacent normal lung tissues surrounding fibrotic regions were selected as the control group using typical sampling method. ii) Specific pathogens free healthy male rats were randomly divided into control group and 5 dust-exposed groups with 10 rats in each group. In dust-exposed group,the rats were exposed to 2 000 mg/m~3 of silica dust for 0,2,4,8,12 and 16 weeks respectively by dynamic inhalation. The rats in control group were given no treatment. iii) Primary cultured rat lung fibroblasts were induced by Ang Ⅱ at a concentration of 100 nmol/L at different time points( 0,5,15 and 30 min,1,3,6,12,24 and 48 hours). iv) The expression of Ac-tubulin α and α-smooth muscle actin( α-SMA) were detected by immunohistochemical staining. The expression of Ac-tubulinα/Vimentin and Ac-tubulin α/α-SMA were observed by immunofluorescence staining. The relative expression ofα-SMA and Ac-tubulin α protein was detected by Western blot. RESULTS: The positive expression of Ac-tubulin α in lung tissue of CWP group was down-regulated while that of α-SMA was up-regulated compared with the control group( P < 0. 01). Immunofluorescence results showed that Vimentin positive expression in the CWP group was significantly increased in the lesion fibrosis area,while Ac-tubulin α expression was absent. The co-expression of Ac-tubulin α and Vimentin was detected in normal lung tissue of control group. The animal experiment results showed that the expression of Ac-tubulin αin lung tissue of rats was down-regulated and that of α-SMA was up-regulated with the prolongation of dust exposure time( P < 0. 01). The Ang Ⅱ induced the differentiation of fibroblasts into myofibroblasts,and the expression of Ac-tubulin α in fibroblasts gradually decreased and the expression of α-SMA gradually increased with the prolongation of Ang Ⅱ induction time( P < 0. 05). CONCLUSION: The lack of expression of Ac-tubulin α may be involved in the occurrence and development of silicotic fibrosis.