Objective: To observe the effects of carboxymethylpachymaran (CMP) on the polarization of macrophages. Method: In vivo

Balb/c mice were injected intraperitoneally with CMP (100 mg·kg-1) as CMP group or saline solutions as control group once daily for 5 consecutive days

and phagocytosis of peritoneal macrophages were investigated. In vitro

RAW264.7 cells were treated with CMP (400

800

1 600 mg·L-1)

lipopolysaccharides (LPS

0.1 mg·L-1) and incubated for 48 h. The expression of CD86 molecule on cells was tested by flow cytometry. Fluorescent microspheres phagocytosed by RAW264.7 cells were analyzed under fluorescence microscope. Nitric oxide (NO) was detected by Griess reagent

and interleukin-6 (IL-6)

interleukin-10 (IL-10)

monocyte chemoattractant protein-1 (MCP-1)

and tumor necrosis factor (TNF) were investigated by Cytometric Bead Array (CBA). Result: The results in vivo showed that both the phagocytic rate and phagocytic index of peritoneal macrophages in CMP group were higher than those in the control group (P < 0.05). The results in vitro showed that the expression of CD86 on macrophages in CMP and LPS-treated groups were higher than those in the control group (P < 0.05). The results by fluorescence microscope showed that the number of macrophages phagocytosing more than 2 microspheres in CMP and LPS-treated groups were more than those in the control group. Flow cytometric analysis showed that both the phagocytic rate and phagocytic index of RAW264.7 cells in CMP and LPS-treated groups were higher than those in the control group (P < 0.05). LPS significantly induced NO

IL-6

IL-10

MCP-1 and TNF secretions in RAW264.7 cells. On the contrary

all CMP-treated groups did not show the secretions of NO

IL-6

IL-10

MCP-1 and TNF in RAW 264.7 cells

with lower secretions of NO

MCP-1 and TNF than those in the control group. Conclusion: CMP can stimulate the activation and phagocytosis of macrophage

but cannot induce the production of inflammation cytokines

which suggests that CMP might promote the M2 phenotype polarization of macrophages.