Objective To observe the expression of HO-1,MT1A,MT2A in human embryonic lung fibroblasts(HELF)induced by supernatant of alveolar macrophage(AM)exposed to silica.Methods Rat AM and HELF were organized into an in vitro model.HO-1,MT1A and MT2A mRNA levels of HELF stimulated by supernatant of AM exposed to silica were detected by RT-PCR technology.Results Expression of HO-1,MT1A and MT2A could be induced by dusted AM and there was good dose-effect relationship between HO-1 mRNA levels and silica concentration...