Cardiac protection of prostacyclin secreted from endothelial progenitor cells against oxidative stress-induced apoptosis：verified by cardiac electrophysiological tests / 中国组织工程研究

ABSTRACT

BACKGROUND:Prostacyclin (PGI2) and its analogs have been reported to prevent pressure overload-induced cardiac hypertrophy, and to reduce cardiac ischemia/reperfusion injury. However, clinical application of PGI2 is chalenging due to its short half-life ( OBJECTIVE:To investigate the protective effectof PGI2-EPCs against oxidative stress-induced cardiomyocyte injury. METHODS:Cultured H9c2 celsin vitrowere assigned into four groups H9c2 cels treated by H2O2for 4 hours. H9c2 cels were pretreated by conditioned medium (colected form EPCs and PGI2-EPCs or colected form EPCs and PGI2-EPCs mixed with native EPCs) before the addition of H2O2. PBS instead of conditioned mediums served as negative control. The paracrine effect of PGI2-EPCs onin vitro angiogenesis of native EPCs was evaluated. MTT and Hoechst 33342 assays were used to examine the protective effect of conditioned medium on H2O2-induced rat embryonic cardiomyocyte apoptosis and cel viability. Finaly, the effect of conditioned medium on the electric activities of adult cardiomyocyteswas measuredby whole-cel patch clamp techniques. RESULTS AND CONCLUSION:When native EPCs mixed with conditioned medium of PGI2-EPCs, the total length of tubes was significantly longer compared with those mixed with CM of EPC. Rat embryonic cardiomyocytes pretreated with conditioned medium of PGI2-EPCs significantly reduced H2O2-induced apoptosis and preserved cel viability compared with pretreatment with EPC-conditioned medium and without pretreatment (P< 0.01). Pretreatment of rat adult cardiomyocyteswith conditioned medium of PGI2-EPCs abolished H2O2-induced early afterdepolarization and shortened H2O2-induced action potential duration prolongation (P< 0.01) towards baseline.Our findings indicate thatPGI2-EPCs protect against oxidative stress-induced cardiomyocyte injury through paracrine action.ThisStudy providesthe groundwork for an innovative cel therapy approach to treat ischemic heart disease.