Figure 6.

STAT3 (signal transducer and activator of transcription 3) inhibitor cancels the cardioprotective effect of MURC (muscle‐restricted coiled‐coil protein) deficiency. A, Left ventricle (LV) systolic function as measured by echocardiography of wild‐type (WT) and MURC knockout (MURC KO) mouse hearts 24 hours after I/R. Vehicle (5% dimethyl sulfoxide) or WP1066 was injected in mice intraperitoneally for 3 consecutive days; n=3 per group. B, Infarct size as measured by triphenyltetrazolium chloride and Evans blue staining of LV tissue from mouse hearts 24 hours after ischemia/reperfusion. The area at risk (AAR) was assessed as a proportion of LV (left), and the infarct size (IS) was assessed as a proportion of the AAR (right); n=3 per group. C, Evaluation of TUNEL (TdT‐mediated dUTP nick‐end labeling) staining for NRCMs transfected with control small interfering RNA (siRNA), MURC siRNA 1, or MURC siRNA 2 after H₂O₂ exposure. Vehicle or WP1066 (a STAT3 inhibitor) was administered to cardiomyocytes; n=3 per group. *P<0.05, **P<0.01. NS indicates not significant.