OBJECTIVETo study the effect of silicosis alveolar macrophages (AM) restimulated by SiO(2) on expression of c-myc oncogene in human embryo lung fibroblasts.

METHODSThe bronchoalveolar lavage of silicosis patients was collected. AMs were divided into 2 groups: (1) SiO(2): AMs were stimulated with SiO(2) (30 microg/ml) for 1, 2, 6, 12, 24 and 36 h; (2) control: treated for the same time without SiO(2). Fibroblasts were cultured with different AMs supernatants for 2 h or 7 h respectively. The expression of c-myc mRNA was determined by RT-PCR and protein by Western Blot.

RESULTSThere was no c-myc expression when fibroblasts were static. The supernatants in the S6 group stimulated expression of c-myc mRNA and protein, with the peak expression at 2 h and 7 h respectively. In the control group, AMs supernatants cultured in different time stimulated expression of c-myc mRNA and protein with the most evident expression at 12 h. The ratios were 0.749 +/- 0.088 and 0.759 +/- 0.101 respectively. Compared with control in the same period, c-myc mRNA and protein expression were significantly stronger treated with the supernatants in which AMs were stimulated for 1 h, 2 h and 6 h by SiO(2) (P < 0.05 or P < 0.01).

CONCLUSIONAMs stimulated with SiO(2) has the ability to induce c-myc oncogene expression in human embryo lung fibroblasts.