Abstract:

Objective    To investigate the inhibitory effect of the polysaccharide of grifola frondosa (PGF) on carbon tetrachloride (CCl4)-induced injury to liver cell line L-02.  Methods    Human liver cell line L-02 was cultured and the CCl4 -induced liver cell injury model was set up . The cells were divided into the normal control group, the CCl4-damaged group and the PGF inhibitory groups (50, 100, 200 and 400μg/mL). MTT assay was used and morphology was observed to measure cell activity. The contents of alanine aminotransferase (ALT) , aspartate aminotranferase (AST) , superoxide dismutase（SOD） and malondialdehyde (MDA) were detected. The changes of mitochondrial membrane potential of L-02 were analyzed by flow cytometry. The concentration of the intracellular calcium ion was determined by Fluo3-AM. Expressions of  bcl-2 and bax proteins were measured by Western blot analysis.  Results     Compared with the CCl4-damaged group, PGF improved the relative survival of L-02, lowered activities of the AST and ALT in medium, prevented the elevation of MDA, kept the high degree of SOD, prevented the decrease of the mitochondrial membrane potential and increase of the concentration of Ca2+,  up-regulated expression of bcl-2, and down-regulated expression of bax. PGF at a concentration of 100μg/mL had the best inhibitory effect. Conclusion    PGF can significantly prevent L-02 cells from damage induced by CCl4, and the mechanism may be related to scavenging free radicals, inhibiting  intracellular calcium overload, stabilizing mitochondrial membrane potential, and regulating expressions of bcl-2 and bax proteins.

Key words: Polysaccharide of Grifola frondosa; CCl4-induced hepaocyte injury; Apoptosis