Constitutively active STAT3 expression in transgenic mice reduced infarct size by 60.3% compared with nontransgenic littermates following ischemia/reperfusion injury.
Does constitutively active STAT3 expression protect against myocardial ischemia/reperfusion injury in mice?
STAT3 activation mediates cardioprotection against ischemia/reperfusion injury in vivo, at least partially through the induction of ROS scavengers MT1 and MT2.
Effect estimate: 60.3% reduction
OBJECTIVE: Activation of signal transducer and activator of transcription 3 (STAT3) was reported to be correlated with myocardial protection against ischemia/reperfusion (I/R) injury in ischemic preconditioning. Here, we tested the causality between STAT3 activity and cardioprotection. We also addressed the molecular mechanism for its cardioprotection. METHODS AND RESULTS: Cardiac-specific transgenic mice expressing constitutively active STAT3 (TG) were generated and exposed to I/R injury. TG hearts exhibited infarcts that reduced by 60.3% in size, compared with nontransgenic littermates (NTG). By measuring dichlorofluorescein (DCF) and 8-isoprostane, reactive-oxygen-species (ROS)-induced metabolites, it was revealed that ROS were generated to lesser extent in TG hearts than in NTG in response to I/R stress. In parallel, ROS scavengers, metallothionein1 (MT1), and metallothionein2 (MT2) were markedly up-regulated in TG hearts. Finally, homozygous deletion of the MT1 and MT2 genes abrogated cardioprotective effect of STAT3 against I/R injury with the cancellation of its ROS-scavenging effects. CONCLUSIONS: Activation of STAT3 protects myocardium from I/R injury in vivo. STAT3 mediates cardioprotection at least partially through MT1 and 2. STAT3 is a potential therapeutic target for I/R injury.
Oshima et al. (Sat,) conducted a other in Ischemia/reperfusion (I/R) injury. Constitutively active STAT3 expression vs. Nontransgenic littermates (NTG) was evaluated on Infarct size (60.3% reduction). Constitutively active STAT3 expression in transgenic mice reduced infarct size by 60.3% compared with nontransgenic littermates following ischemia/reperfusion injury.