Effects of DNA methylation of thymocyte differentiation antigen-1 in beryllium sulfate induced human fetal lung fibroblast fibrosis / 中国职业医学

ABSTRACT

OBJECTIVE: The change of DNA methylation of thymocyte differentiation antigen-1( Thy-1) was observed in beryllium sulfate( Be SO4) stimulated human fetal lung fibroblast( MRC-5 cell) to explore the effects of Thy-1 in Be SO4 induced lung fibrosis. METHODS: MRC-5 cell culture in vitro model was used. The final concentrations of Be SO4were1. 0,10. 0 and 100. 0 μmol / L( low-,medium- and high-dose groups). The control was untreated. Other 2 intervention groups were the 5-azacytidine( AZC) intervention group( 10. 0 μmol / L of AZC and 10. 0 μmol / L Be SO4) and the trichostatin A( TSA) intervention group( 0. 5 μmol / L of TSA and 10. 0 μmol / L Be SO4). The cells were collected 24,48 and 72 hours after exposure. Real-time quantitative polymerase chain reaction( PCR) was used to determine the relative expression of collagen typeⅠ( Col Ⅰ),collagen type Ⅲ( Col Ⅲ),α-smooth muscle actin( α-SMA) and Thy-1 mRNA.The nested landed methylation specific PCR was used to detect the Thy-1 DNA methylation level. RESULTS: At 24 hours,the relative expression level of Col Ⅲ mRNA in MRC-5 cells showed an increasing trend with increasing dose( P < 0. 05);at 48 and 72 hours,the relative expression levels of Col Ⅰ,Col Ⅲ and α-SMA mRNA in MRC-5 cells increased with the increasing dose( P < 0. 05). All these 3 indicators in MRC-5 cells of 3 dose groups increased with the increase of expose time( P < 0. 05). The relative expression level of Thy-1 mRNA in MRC-5 cells of all 3 dose groups were lower than that in control( P < 0. 05). The relative expression level of Thy-1 mRNA of the high-dose group was lower than that of the lowdose group( P < 0. 05). The Thy-1 DNA methylation levels in the medium- and high-dose groups were both higher than that of the control( P < 0. 05). The Thy-1 DNA methylation levels of the 3 dose groups increased with the increasing dose( P < 0. 05). The Thy-1 DNA methylation levels of MRC-5 cells in the 2 intervention groups were higher than that of the control( P < 0. 05),but there was no significant difference when compared with the medium-dose group( P > 0. 05).CONCLUSION: Be SO4 stimulation can induce the fibrosis of MRC-5 cells. In this process,the Thy-1 DNA methylation level increases,while the Thy-1 mRNA expression level decrease. Thy-1 DNA methylation might be one of the important mechanisms of lung fibrosis induced by Be SO4.