대한대장항문학회

Ischemic preconditioning (IPC) is a phenomenon that a brief episode of ischemia to a tissue renders the tissue resistance from a subsequent prolonged ischemia. It is generally accepted that this protection is a receptor-mediated process, and is realized<br>via signal transduction pathways. Protein kinase C (PKC), known to play key regulatory roles in cellular processes, has been proposed as a primary cellular mediator of preconditioning. However, the role of PKC in eliciting cardioprotection remains<br>controversial. The evidences for the 'PKC hypothesis' of preconditioning in various tissue and organs are summarized. Especially in intestine, a brief ischemia induced a reversible epithelial injury to the jejunum that is associated with activation of<br>several PKC isoforms. Injury induced by an additional period of ischemia is reduced by the prior IPC, and this effect is abolished by non-selective PKC inhibition but not by a selective inhibitor of cPKC/or PKCdelta. This result suggest that<br>activation of nPKC isoform (especially PKCepsilon) during and following ischemic insults may play an important role in protection against I/R injury in the intestine, and this mechanism is identical with previous study in heart tissue.<br>