Chitosan oligosaccharides protect human umbilical vein endothelial cells from hydrogen peroxide-induced apoptosis

This study aimed to investigate the protective effect of chitosan oligosaccharides (COS) on human umbilical vein endothelial cell (HUVEC) apoptosis induced by hydrogen peroxide (H2O2). We found that COS not only reversed the decrease of cell viability and proliferation activity, but ameliorated nuclear chromatin damage in H2O2-induced HUVECs. Additionally, COS contributed to the decrease of cytosolic Ca2+ level, increase of mitochondrial membrane potential, up-regulation of Bcl-2 mRNA, down-regulation of Bax mRNA, reduction of cleaved caspase-3 protein, inhibition of phosphorylated p38 mitogen-activated protein kinase (MAPK) and induction of phosphorylated Akt in HUVECs. Further, H2O2-induced caspase-3 activation could be suppressed by p38 MAPK inhibitor (SB203580) and up-regulated by phosphatidylinositol-3-kinase (PI3K) inhibitor (LY294002), indicating the involvement of p38 MAPK and PI3K/Akt signaling pathways. In conclusion, the results show that COS may effectively inhibit the H2O2-induced HUVEC apoptosis.