Abstract: The aim of the present study was to investigate the immunomodulatory effect of low-molecular-mass selenoaminopolysaccharide (LSA) in RAW264.7 cells. The effects of LSA and sodium selenite (Se) on the proliferation of RAW264.7 cells were detected by MTT assay. Neutral red test was used to investigate the effect of LSA on phagocytosis and cell morphology in RAW264.7 cells. Enzyme-linked immunoabsorbent assay and real-time fluorescent quantitative reverse transcription-polymerase chain reaction were used to explore the effects of different selenium concentrations of LSA on the secretion and mRNA expression of cytokines (tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-10) in RAW264.7 cells. The results revealed that LSA did not affect cell viability at selenium concentrations between 100 and 1000 μg/L. Sodium selenite significantly inhibited cell viability at selenium concentrations more than 200 μg/L. LSA contributed significantly to phagocytic activity in RAW264.7 cells. In addition, LSA could significantly increase the secretion and gene expression levels of TNF-α, IL-6 and IL-10 in RAW264.7 cells. Taken together, these findings suggested that LSA has immunomodulatory activity on macrophage cell line RAW264.7.

Key words: selenium, low-molecular-mass seleno-aminopolysaccharide, macrophage, immunomodulatory