title: ROS-mediated lipopolysaccharide-induced apoptosis in INS-1 cells by modulation of Bcl-2 and Bax.
abstract: Overproduction of reactive oxygen species (ROS) or exhaustion of antioxidants may cause oxidative stress which is a major factor of defective insulin secretion and increases apoptosis of pancreatic β-cells in diabetes. So there comes a consideration of whether antioxidant strategies can be used to protect deterioration of the β-cells. In this study, we explored the mechanism of oxidative stress mediated lipopolysaccharide (LPS) induced apoptosis in insulin secreting (INS-1) cells from a rat pancreatic β-cell line. ROS was monitored by using intracellular ROS capture dihydroethidium (DHE) and dihydrorhodamine123 (DHR123). Apoptosis rate was measured by flow cytometry (FCM). The pro-apoptotic gene Bax and anti-apoptotic gene Bcl-2 were analysed by Western blot and RT-PCR. The results demonstrate that LPS-stimulated INS-1 cells manifest intensified intracellular fluorescence in both dose- and time- dependent manners. Apoptosis rate of LPS stimulated INS-1 cells is significantly increased by FCM, with a significant increase in Bax/Bcl-2 ratio revealed by Western blot and RT-PCR. Furthermore, α-lipoic acid (α-LA) inhibits LPS-induced apoptosis, but can not restore the function of glucose stimulated insulin secretion (GSIS) in INS-1 cells.
authors.affiliation: Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Department of Endocrinology, Shanghai, China.
authors.forename: S-C
authors.initials: SC
authors.lastname: DU
authors.forename: Q-M
authors.initials: QM
authors.lastname: Ge
authors.forename: N
authors.initials: N
authors.lastname: Lin
authors.forename: Y
authors.initials: Y
authors.lastname: Dong
authors.forename: Q
authors.initials: Q
authors.lastname: Su
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D003920:Diabetes Mellitus; D050417:Insulin-Secreting Cells / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism; D008070:Lipopolysaccharides / Q000276:immunology; D018384:Oxidative Stress / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D008063:Thioctic Acid / Q000494:pharmacology; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
chemical_list: D008070:Lipopolysaccharides; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D008063:Thioctic Acid