Upregulation of heme oxygenase gene expression in rat lung epithelial cells following exposure to cadmium.

Inhalation exposure to cadmium (Cd) is associated with inflammatory lesion in the lung. In the present study we have investigated cytotoxic effects of Cd on immortalized rat lung epithelial cells (SV40-T2) and gene expression in those cells following in vitro exposure to sublethal concentrations of cadmium chloride (CdCl(2)). The polymerase chain reaction (PCR)-based subtraction method was used to find differentially expressed genes between control and Cd-exposed SV40-T2 cells. The most prominent cDNA on an agarose gel was identical to a fragment of rat heme oxygenase (HO) gene. Northern blot analysis indicated that the level of HO mRNA expression in SV40-T2 cells was increased to 38-fold of the control value following exposure to 2.5 microM CdCl(2) for 4 h. These results suggest that HO gene expression is one of the most sensitive biomarkers for acute exposure to Cd in the lung.