Genistein augments prostaglandin-induced recovery of barrier function in ischemia-injured porcine ileum

Abstract

We have previously shown that PGE2 enhances recovery of transmucosal resistance ( R) in ischemia-injured porcine ileum via a mechanism involving chloride secretion. Because the tyrosine kinase inhibitor genistein amplifies cAMP-induced Cl− secretion, we postulated that genistein would augment PGE2-induced recovery of R. Porcine ileum subjected to 45 min of ischemia was mounted in Ussing chambers, and R and mucosal-to-serosal fluxes of [3H] N-formyl-methionyl-leucyl phenylalanine (FMLP) and [3H]mannitol were monitored as indicators of recovery of barrier function. Treatment with genistein (10− 4 M) and PGE2(10− 6 M) resulted in synergistic elevations in R and additive reductions in mucosal-to-serosal fluxes of [3H]FMLP and [3H]mannitol, whereas treatment with genistein alone had no effect. Treatment of injured tissues with genistein and either 8-bromo-cAMP (10− 4 M) or cGMP (10− 4 M) resulted in synergistic increases in R. However, treatment of tissues with genistein and the protein kinase C (PKC) agonist phorbol myristate acetate (10− 5–10− 6M) had no effect on R. Genistein augments recovery of Rin the presence of cAMP or cGMP but not in the presence of PKC agonists.