Use of genetically altered animal models in understanding the role of metallothionein in cadmium toxicity

Acute Cd exposure produces liver injury, whereas chronic Cd exposure damages the kidney but not the liver. Previous experiments suggest that the low-molecular-weight, metal-binding protein metallothionein (MT) in liver protects against liver injury, but is responsible for the kidney injury observed after chronic Cd exposure. Thus, prior to the development of MT-transgenic and MT-knockout mice models, MT's role was always assumed to be a toxicological paradox, hepatoprotection but nephrotoxicity. The development of MT-transgenic and MT-knockout mice models has reconfirmed MT's protective role against Cd-induced hepatotoxicity, but it has challenged MT's suggested role in Cd-induced nephrotoxicity. In this communication, recent data using these genetically altered mice models indicate that MT protects against not only the Cd-induced hepatotoxicity, but also nephrotoxicity, hematotoxicity, immunotoxicity, and bone damage.