RESUMEN
<p><b>OBJECTIVE</b>To explore the DNA methylation levels of genome in cFb transdifferentiation induced by SiO2 in rats.</p><p><b>METHODS</b>The primary macrophages and fibrocytes of SD rats were co-cultured directly and indirectly, which were exposed to SiO2 at the doses of 25, 50 and 100 g/ml. The transdifferentiation of cFb was identified with immunohistochemical assay. The genomic DNA methylation levels of cFb were detected with HPLC.</p><p><b>RESULTS</b>Under the condition of indirect co-culture, as compared with control group, the genomic DNA methylation levels of cFb exposed to SiO2 at the doses of 25, 50 and 100 g/ml reduced by 19.9%, 26.9% and 30.3%, respectively (P < 0.05); as compared with cFb exposed to 100 g/ml SiO2, the genomic DNA methylation levels of cFb exposed to 5-aza-dC decreased by 22.0% (P < 0.05). Under the condition of ThinCert(TM) direct co-culture, as compared with control group, the genomic DNA methylation levels of cFb exposed to SiO2 at the doses of 25, 50 and 100 g/ml reduced by 22.2%, 30.2% and 36.7%, respectively (P < 0.05); as compared with cFb exposed to 100 g/ml SiO2, the genomic DNA methylation levels of cFb exposed to 5-aza-dC decreased by 20.6% (P < 0.05).</p><p><b>CONCLUSION</b>Under the co-culture condition in vitro, SiO2 could reduce the genomic DNA methylation levels of cFb. The ThinCert(TM) direct co-culture can be used to study the silicosis fibrosis.</p>