Chitooligosaccharides protect pancreatic β-cells from hydrogen peroxide-induced deterioration

Chitooligosaccharides (COS) of four different molecular weight ranges (below 1 kDa, 1–3 kDa, 3–5 kDa and 5–10 kDa) were investigated for their ability to protect β-cells from damage induced by hydrogen peroxide. The viability of HIT-T15 pancreatic β-cells was found by MTT assay to be significantly reduced after 4 h of treatment with 150 μM H2O2. Chitooligosaccharides (500 μg/ml) with molecular weights of 3–5 kDa raised cell viability to 58.46% following H2O2 addition. The radical scavenging effect of chitooligosaccharides was examined by dichlorofluorescein assay. In addition to free radical scavenging, the effect of chitooligosaccharides on oxidative-stress related enzymes and genes was tested. In agreement with the expression levels of related genes, results of cell viability and cellular radical scavenging assays indicate that chitooligosaccharides protect β-cells from oxidative-stress-induced cellular damage, presumably due to radical scavenging activity.