Expression data from C57BL/6 and MRL/MpJ heart left ventrical with LAD ligation

Previous studies have suggested that the heart may be capable of limited repair and regeneration in response to a focal injury while other studies indicate that the mammalian heart has no regenerative capacity. To further explore this issue, we performed a series of superficial and transmural myocardial injuries in C57BL/6 and MRL/MpJ adult mice. At defined time intervals following the respective injury (Days 3, 14, 30 and 60) we examined cardiac function using echocardiography, morphology, FACS cell sorting for BrdU positive cells and molecular signature using microarray analysis. We observed complete restoration of myocardial function in the superficial MRL cryoinjured heart and significantly less scar formation as compared to the injured hearts of C57BL/6 mice. Following a severe transmural myocardial injury, the MRL mouse has increased survival and decreased ventricular remodeling compared to the C57BL/6 mouse but without evidence of significant regeneration. The cytoprotective program observed in the severely injured MRL heart is in part due to increased vasculogenesis and decreased apoptosis that limits the extension of the injury. We conclude that C57BL/6 and MRL injured hearts have evidence of limited myocardial regeneration, in response to superficial injury, but the improved function and survival observed in the MRL mouse heart following severe injury is not due to significant regenerative processes. Keywords: time course Mouse hearts from C57BL/6 and MRL/MpJ strains were injured with LAD ligation and harvested at 3, 30 and 60 days after treatement.