title: Padina arborescens extract protects high glucose-induced apoptosis in pancreatic β cells by reducing oxidative stress.
abstract: OBJECTIVE
  This study investigated whether Padina arborescens extract (PAE) protects INS-1 pancreatic β cells against glucotoxicity-induced apoptosis.
  
  
  METHODS
  Assays, including cell viability, lipid peroxidation, generation of intracellular ROS, NO production, antioxidant enzyme activity and insulin secretion, were conducted. The expressions of Bax, Bcl-2, and caspase-3 proteins in INS-1 cells were evaluated by western blot analysis, and apoptosis/necrosis induced by high glucose was determined by analysis of FITC-Annexin V/PI staining.
  
  
  RESULTS
  Treatment with high concentrations of glucose induced INS-1 cell death, but PAE at concentrations of 25, 50 or 100 µg/ml significantly increased cell viability. The treatment with PAE dose dependently reduced the lipid peroxidation and increased the activities of antioxidant enzymes reduced by 30 mM glucose, while intracellular ROS levels increased under conditions of 30 mM glucose. PAE treatment improved the secretory responsiveness following stimulation with glucose. The results also demonstrated that glucotoxicity-induced apoptosis is associated with modulation of the Bax/Bcl-2 ratio. When INS-1 cells were stained with Annexin V/PI, we found that PAE reduced apoptosis by glucotoxicity.
  
  
  CONCLUSIONS
  In conclusion, the present study indicates that PAE protects against high glucose-induced apoptosis in pancreatic β cells by reducing oxidative stress.
authors.affiliation: Department of Food and Nutrition, College of Medical and Life Science, Silla University, Busan 617-736, Korea.
authors.forename: Mi Hwa
authors.initials: MH
authors.lastname: Park
authors.affiliation: Department of Food Science and Nutrition, Pusan National University, 2, Busandaehak-ro 63beon-gil, Geumjeong-gu, Busan 609-735, Korea.
authors.forename: Ji-Sook
authors.initials: JS
authors.lastname: Han
keywords: INS-1 pancreatic β cell; Padina arborescens extract; apoptosis; high glucose; oxidative stress