Abstract
High glucose levels induce cell death in many cell types, including pancreatic β‐cells. Although protective agents against glucotoxicity have been searched for extensively, so far none have been found. In this report, we tested silk fibroin (SF) as a candidate material for antiglucotoxicity in the pancreatic β‐cell (HIT‐T15 cell) line. Approximately 50% of cells were killed after treatment with 80 mg/mL glucose. This reduction of cell number was recovered by the addition of SF at 50 mg/mL. SF treatment also decreased cellular reactive oxygen species (ROS) and increased proliferating cellular nuclear antigen (PCNA) immunoreactivity. In addition, TUNEL assays demonstrated that SF protects against glucose‐induced apoptosis of HIT‐T15 cells, suggesting that SF might protect cells from cell death by lowering cellular ROS levels. SF also induced expression of the insulin‐like growth factor‐1 (IGF‐1) gene, and IGF‐1 expression may be the cause of SF‐induced protection against glucose toxicity. Taken together, these results suggest that SF could serve as a potential therapeutic agent to treat the hyperglycemia‐induced death of pancreatic β‐cells. © 2010 Wiley Periodicals, Inc. J Biochem Mol Toxicol 25:238–243, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.20381