Comparison of the protective effects of chitosan oligosaccharides and chitin oligosaccharide on apoptosis, inflammation and oxidative stress.

Chitin degradation products, especially chitosan oligosaccharides (COSs), are highly valued in various industrial fields, such as food, medicine, cosmetics and agriculture, for their rich resources and high cost-effectiveness. However, little is known about the impact of acetylation on COS cellular bioactivity. The present study aimed to compare the differential effects of COS and highly N-acetylated COS (NACOS), known as chitin oligosaccharide, on HO-induced cell stress. MTT assay showed that pretreatment with NACOS and COS markedly inhibited HO-induced RAW264.7 cell death in a concentration-dependent manner. Flow cytometry indicated that NACOS and COS exerted an anti-apoptosis effect on HO-induced oxidative damage in RAW264.7 cells. NACOS and COS treatment ameliorated HO-induced RAW264.7 cell cycle arrest. Western blotting revealed that the anti-oxidation effects of NACOS and COS were mediated by suppressing expression of proteins involved in HO-induced apoptosis, including Bax, Bcl-2 and cleaved PARP. Furthermore, the antagonist effects of NACOS were greater than those of COS, suggesting that acetylation was essential for the protective effects of COS.