To confirm microarray results at the translation product level, Western blot analysis was performed on selected proteins. As shown in Figure 2, expression of GST-pi (32 kDa) and multi-drug resistance-associated protein-1 (MRP1, 190 kDa) and the expression of P-glycoprotein (170 kDa) were increased. Expression of TNFR1 (47 kDa) and tumor necrosis factor receptor associated death domain (TRADD) (20 kDa) are in agreement with microarray and RT-PCR analysis. The expression of -actin (43 kDa) was similar between groups.
DISCUSSION
The current study demonstrated that inhalation exposure to Hg0 vapor produced significant alterations in gene expression in the lung without causing histopathological changes. Alterations in the genes encoding inflammatory responses, adaptive mechanisms, transporters, and signal transduction were probably an attempt to cope with mercury-induced stress to the lung. Among 588 genes examined, the expression of 36 genes was increased more than twofold with p 0.05; while the expression of 25 genes was depressed to below 65% of air