Green-tea polyphenol (-)-epigallocatechin-3-gallate provides resistance to apoptosis in isolated islets

Abstract

Background/Purpose: Apoptosis resulting from disruption of the normal cell-matrix relationship (anoikis) during islet isolation, and the reactive oxygen and nitrogen species generated following hypoxia/ reoxygenation (H/R) can lead to a loss of islet tissue in culture and the reduced survival of transplanted pancreatic islets. The aim of this study was to investigate the effect of (-)-epigallocatechin-3-gallate (EGCG), a well-known antiapoptotic agent, on inhibiting anoikis and H/R injury in an in vitro islet culture system. Methods: Islets were isolated from F344 rats and cultured under normal or H/R condition with/without EGCG. Results: EGCG inhibited apoptosis and lactate-dehydrogenase leakage from anoikis and H/R in a dose-dependent manner. Further, EGCG prevent increases in 8-hydroxy-2′-deoxyguanosine content and inhibited the decline of insulin secretory function induced by H/R. Conclusions: These results suggest that the addition of EGCG to an islet culture system may improve the survival rate of isolated islets and reduce the loss of functional islet mass that compromises the stable reversal of diabetes after islet transplantation. © Springer-Verlag Tokyo 2007.