Isolation and Purification of Chitosan Oligosaccharides (Mw ≤ 1000) and Their Protective Effect on Acute Liver Injury Caused by CCl 4 .

Chitosan oligosaccharides are the degradation products of chitin obtained from the shell extracts of shrimps and crabs. Compared with chitosan, chitosan oligosaccharides have better solubility and a wider application range. In this study, high-molecular-weight chitosan oligosaccharides (COST, chitosan oligosaccharides, MW ≤ 1000) were isolated and purified by a GPC gel column, and the molecular weight range was further reduced to obtain high-purity and low-molecular-weight chitosan (COS46). Compared with COST, COS46 is better at inhibiting CCl 4 -induced cell death, improving cell morphology, reducing ALT content, and improving cell antioxidant capacity. The effects of COST and COS46 on CCl 4 -induced acute liver injury were further verified in mice. Both COS46 and COST improved the appearance of the liver induced by CCl 4 , decreased the levels of ALT and AST in serum, and decreased the oxidation/antioxidant index in the liver. From the liver pathological section, the effect of COS46 was better. In addition, some indicators of COS46 showed a dose-dependent effect. In conclusion, compared with COST, low-molecular-weight COS46 has better antioxidant capacity and a better therapeutic effect on CCl 4 -induced acute liver injury.