Effects of lead and/or cadmium on the expression of metallothionein in the kidney of rats.

Lead acetate (300 mg/L) and/or cadmium chloride (50 mg/L) were administered as drinking water of Sprague-Dawley rats for 8 weeks to investigate the possible combined effect of these metals on the expression of metallothionein (MT) in kidneys. Immunohistochemical staining and real-time quantitative polymerase chain reaction analyses were performed on kidney samples to identify the distribution of MT and to quantify the relative expression levels of MT-1 and MT-2 gene, respectively. There is no significant difference in distribution of the intensity, amount of MT immunostaining, and expression level of MT-1 and MT-2 gene in the kidneys between the lead group and control group (P > 0.05), whereas those in the cadmium group and (Pb + Cd) group were significantly higher than that in the control group (P < 0.01). Compared to the (Pb + Cd) group with the lead or cadmium group, the expression level of MT-1 and MT-2 gene increased significantly (P < 0.01). In summary, there was an obvious synergistic effect of lead combined with cadmium on the expression of metallothionein in the kidney of rats.