a, e The lung metastasis was observed using an in vivo imaging system. b, f The body weight of mice was recorded every 3 days for 21 days or 15 days. c Representative lung tissue in each group. d CD68 and CD206 positive cells in lung tissue were detected by immunofluorescence using FITC-CD68 and PE-CD206 antibody. All data are presented as means ± SD, n = 7, *P < 0.05, **P < 0.01 vs. control group.