Yuma Wada1, Atsushi Takata1, Tetsuya Ikemoto2, Yuji Morine1, Satoru Imura1, Shuichi Iwahashi1, Yu Saito1, Mitsuo Shimada1. 1. Department of Surgery, Graduate School of Biomedical Sciences, Tokushima University, 3-18-15 Kuramoto-cho, 770-8503, Tokushima, Japan. 2. Department of Surgery, Graduate School of Biomedical Sciences, Tokushima University, 3-18-15 Kuramoto-cho, 770-8503, Tokushima, Japan. ikemoto.tetsuya@tokushima-u.ac.jp.
Abstract
PURPOSE: Epigallocatechin 3-gallate (EGCG), a green tea polyphenol, has been shown to have anti-oxidant and anti-inflammatory effects in vitro and in vivo. The aim of this study was to investigate the effects and mechanism of EGCG on isolated pancreatic islets as pre-conditioning for pancreatic islet transplantation. METHODS: The pancreatic islets were divided into two groups: an islet culture medium group (control) and an islet culture medium with EGCG (100 µM) group. We investigated the islet viability, Nrf2 expression, reactive oxygen species (ROS) production, and heme oxygenase-1 (HO-1) mRNA. Five hundred islet equivalents after 12 h of culture for the EGCG 100 µM and control group were transplanted under the kidney capsule of streptozotocin-induced diabetic ICR mice. RESULTS: The cell viability and insulin secretion ability in the EGCG group were preserved, and the nuclear translocation of Nrf2 was increased in the EGCG group (p < 0.01). While the HO-1 mRNA levels were also higher in the EGCG group than in the control group (p < 0.05), the ROS production was lower (p < 0.01). An in vivo functional assessment showed that the blood glucose level had decreased in the EGCG group after transplantation (p < 0.01). CONCLUSION: EGCG protects the viability and function of islets by suppressing ROS production via the Nrf2 pathway.
PURPOSE:Epigallocatechin 3-gallate (EGCG), a green tea polyphenol, has been shown to have anti-oxidant and anti-inflammatory effects in vitro and in vivo. The aim of this study was to investigate the effects and mechanism of EGCG on isolated pancreatic islets as pre-conditioning for pancreatic islet transplantation. METHODS: The pancreatic islets were divided into two groups: an islet culture medium group (control) and an islet culture medium with EGCG (100 µM) group. We investigated the islet viability, Nrf2 expression, reactive oxygen species (ROS) production, and heme oxygenase-1 (HO-1) mRNA. Five hundred islet equivalents after 12 h of culture for the EGCG 100 µM and control group were transplanted under the kidney capsule of streptozotocin-induced diabetic ICR mice. RESULTS: The cell viability and insulin secretion ability in the EGCG group were preserved, and the nuclear translocation of Nrf2 was increased in the EGCG group (p < 0.01). While the HO-1 mRNA levels were also higher in the EGCG group than in the control group (p < 0.05), the ROS production was lower (p < 0.01). An in vivo functional assessment showed that the blood glucose level had decreased in the EGCG group after transplantation (p < 0.01). CONCLUSION:EGCG protects the viability and function of islets by suppressing ROS production via the Nrf2 pathway.
Entities:
Keywords:
Epigallocatechin 3-gallate (EGCG); Islet transplantation; Nuclear factor erythroid 2-related factor 2 (Nrf2); Pre-conditioning; Reactive oxygen species (ROS) production
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