Schisandrin B decreases the sensitivity of mitochondria to calcium ioninduced permeability transition and protects against ischemia- reperfusion injury in rat hearts

Aim： In order to elucidate the molecular mechanism underlying the cardioprotection afforded by schisandrin B （Sch B）, the effect of Sch B treatment on the sensitivity of mitochondria to Ca^2＋-stimulated permeability transition （PT） was investigated in rat hearts under normal and ischemia-reperfusion （I-R） conditions. Results： Myocardial I-R injury caused an increase in the sensitivity of mitochondria to Ca^2＋ -stimulated PT in vitro. The enhanced sensitivity to mitochondrial PT was associated with increases in mitochondrial Ca^2＋ content as well as the extent of reactive oxidant species production in vitro and cytochrome c release in vivo. The cardioprotection afforded by Sch B pretreatment against I-R-induced injury was paralleled by the decrease in the sensitivity of myocardial mitochondria to Ca^2＋ -stimulated PT, particularly under I-R conditions. Conclusion： The results suggest that Sch B treatment increases the resistance of myocardial mitochondria to Ca^2＋ -stimulated PT and protects against I-R-induced tissue injury.