MSCs were treated with interleukin (IL)-1¦Â and/or transforming growth factor (TGF)-¦Â1 for 24 hours before experiments. VEGF production was determined by enzyme-linked immunosorbent assay. Isolated hearts from adult male Sprague-Dawley rats were subjected to 15 minutes of equilibration, 25 minutes of ischemia, and 40 minutes reperfusion. Hearts (n = 5-7 per group) were randomly infused with vehicle, untreated MSCs, or MSCs pretreated with IL-1¦Â and/or TGF-¦Â1. Specific inhibitors were used to delineate the roles of p38 mitogen-activated protein kinase (MAPK) and SMAD3 in IL-1¦Â- and TGF-¦Â1-mediated stimulation of MSCs.
MSCs cotreated with IL-1¦Â and TGF-¦Â1 exhibited synergistically increased VEGF secretion, and they greatly improved postischemic myocardial functional recovery. Ablation of p38 MAPK and SMAD3 activation with specific inhibitors negated both IL-1¦Â- and TGF-¦Â1-mediated VEGF production in MSCs and the ability of these pretreated MSCs to improve myocardial recovery after ischemia.
Pretreating MSCs with 2 cytokines may be useful to fully realize the potential of cell-based therapies for ischemic tissues.