Preparation of a series of chitooligomers and their effect on hepatocytes

A series of chitooligomers with molecular weight ranging from 1.7 ∼ 3.8 × 103 were prepared by degradation of a high molecular weight chitosan with hydrogen peroxide and selective precipitation in ethanol solutions. The prepared chitooligomers were characterized by gel permeation chromatography, elemental analysis, Fourier transform infrared spectra, 13C nuclear magnetic resonance spectroscopy and X-ray diffraction analysis. Cell culture experiments suggested that the effect of the chitooligomers on the proliferation of L02 hepatocytes was dependent on culture time, namely, at the initial stage of culture there was an inhibitory effect on proliferation of the cells; however, the cultures recovered in cell proliferation and exhibited promotion effect in following days. In the case of chitosan monomer (GlcN), high concentration of GlcN (1 mg/ml) produced a significant suppression in proliferation of L02 cells relative to control, with decreases of 35.2%, 60% and 72.9% on days 1, 3 and 5, respectively. In addition, there was no significant effect of the chitooligomers on the functions of albumin secretion and urea synthesis of the hepatocytes.