Metallothionein inhibits ischemia-reperfusion injury in mouse heart

Oxidative stress is believed to play a major role in ischemia-reperfusion injury to the heart. Metallothionein (MT), a potential free radical scavenger, may function in cardiac protection against ischemia-reperfusion damage. To test this hypothesis, a specific cardiac MT-overexpressing transgenic mouse model was used. The hearts isolated from these animals were subjected to 50 min of warm (37 degrees C) zero-flow ischemia followed by 60- or 90-min reflow. Compared with the nontransgenic controls, the transgenic mouse hearts with MT concentrations approximately 10-fold higher than normal showed significantly improved recovery of contractile force postischemia (69.2 +/- 4.2 vs. 26.0 +/- 6.0% at the end of 60-min reperfusion, P < 0.01). Efflux of creatine kinase from these transgenic hearts was reduced by more than 50% (P < 0.01). In addition, the zone of infarction induced by ischemia-reperfusion at the end of 90-min reperfusion was suppressed by approximately 40% (P < 0.01) in the transgenic hearts. The results strongly indicate that MT provides protection against ischemia-reperfusion-induced heart injury.