Protective effect of soluble eggshell membrane protein hydrolysate on cardiac ischemia/reperfusion injury

BACKGROUND: Soluble eggshell membrane protein (SEP) has been proved to hold the antioxidant activity. The functional role of SEP on cardioprotection was investigated in vivo and in vitro. METHODS: Rats and cardiomyocytes were pretreated with SP2, a hydrolysate attained from SEP, and then subjected to ischemia/reperfusion (I/R) or hypoxia/reoxygenation (H/R) and hydrogen peroxide, respectively. The measurement of myocardial infarct size, cell apoptosis assay, cell viability assay, and caspase activity assay were performed on rats and cardiomyocytes. RESULTS: The results showed that the treatment of SP2 induced the resistance to I/R or H/R injury on rats and cardiomyocytes as indicated by decreased infarct size and decreased cellular apoptosis. The cardioprotective roles of SP2 were partly resulted from the downregulated expression and activity of caspase-3 in which the effect was similar to the caspase inhibitor, z-VAD-fmk, and could be rescued by caspase activator, PAC-1. CONCLUSIONS: This investigation has demonstrated that SP2 attenuated the damage of I/R and H/R on rats and cardiomyocytes by the caspase-dependent pathway. This cardioprotective effect of SP2 suggested a novel therapeutic agent of SEP for ischemic-related heart diseases.