Abstract

BACKGROUND
Mechanism for glucose toxicity is known to be an increased oxidative stress produced by multiple pathways. In our previous report, 2-deoxy-d-ribose (dRib) promoted apoptosis by increasing oxidative stress in a pancreatic beta-cell line. We performed this study to investigate the mechanism of dRib-induced damage of beta-cells. METHODS: HIT-T15 cells were cultured in RPMI-1640 medium with 40 mM dRib for 24 hours after pretreatment with various concentrations of a metal chelator (DTPA) and inhibitors of protein glycation (aminoguanidine and pyridoxamine). Cell viability was determined by MTT assay. Apoptosis was analyzed by flow cytometry with annexin V/PI double staining. RESULTS: DTPA, which inhibits the monosaccharide autoxidation, partially reversed dRib-induced cytotoxicity in a dose-dependent manner (P < 0.01). The cytotoxicity was also suppressed dose-dependently by aminoguanidine (AG) and pyridoxamine (PM) (P < 0.05 and P < 0.01, repectively). Flow cytometric analysis showed that pretreatment of DTPA and AG also reversed the dRib-triggered apoptosis in a dose-dependent manner. We assessed the additional protective effects of inhibitors of protein glycation from dRib-induced cytotoxiciy in the presence of a metal chelator. The additions of AG (P < 0.05) and PM (P < 0.01) significantly reduced the cytotoxicity compared with DTPA alone group. CONCLUSION: This results suggest that dRib produce cytotoxicity and apoptosis through the mechanisms of advanced glycation endproducts (AGEs) formation including the monsaccharide autoxidation and protein glycation in pancreatic beta-cell. Thus, dRib could be a surrogate for glucose in the study of glucose toxicity and chronic diabetic complications.

• Keywords: Autoxidation;Glucose toxicity;Oxidative stress;Protein glycation;beta-cell apoptosis;2-deoxy-D-ribose