Protective Effect of NecroX-7 on Islets against Oxidative Stress and Inflammation

Oxidative stress generated during islet isolation, culture, and transplantation causes islet cell damage mediated by hypoxia, reactive oxygen species (ROS) and inflammatory responses. We investigated the protective effects of NecroX-7, a novel ROS scavenger, during isolation and/or culture of islets. For ex vivo studies, islets from heterozygote human islet amyloid polypeptide (hIAPP^+/-) mice and C57BL/6J mice were isolated by collagenase with and without supplementation with 20 uM of NecroX-7. Supplementation with NecroX-7 provided markedly increased islet viability and ATP contents, and attenuated ROS, transcription of c-Jun N-terminal kinases, high mobility group box-1 (HMGB1) and proinflammatory cytokines including interleukin-1beta (IL-1b), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-a). Transplantation of islets, which is derived from islet isolation method using supplementation with NecroX-7, into syngeneic subrenal subcapsular of hIAPP^+/- mice also improved post-transplant blood glucose levels. Also, NecroX-7 protected RINm5F cells from t-BHP-induced and serum deprivation induced toxicity in in vitro culture by dose-dependent manner from 0.1 uM to 20 uM. Supplementation of medium with NecroX-7 during serum-deprived culture condition also improved impaired viability and serum deprivation-induced ROS in islets from hIAPP^+/- mice by dose-dependent manner from 0.1 uM to 20 uM. These findings suggest that NecroX-7 supplementation during the islet isolation and/or culture process suppressed inflammatory responses and ROS induced by serum deprivation and provides a potential benefit to improve post-transplantation outcomes.