Abstract: Objective To investigate the effect of galanin on mouse RAW264.7 macrophage cell line. Methods RAW264.7 mouse macrophage cells were cultured in DMEM （100 U/ml of penicillin and 100g/ml of streptomycin) containing 10% FBS at 37℃，in a humidified 5% CO2 atmosphere. Cells were divided into three groups，namely the control group （vehicle only)，lipopolysaccharides （LPS） group（LPS only） and galanin treatment group （LPS plus galanin）. Cells were serum-starved for 4 h followed by LPS（1μg/ml） or vehicle incubation for 2 h；Cell were then incubated with or without galanin（1000nmol/L） for 24 h. Cell morphology was observed under the microscope；mRNA levels of tumor necrosis factor-α（TNF-α），interleukin-6（IL-6） and interleukin-1β（IL-1β）were measured by real-time RT-PCR and Western blotting analysis were performed to determine the inducible nitric oxide synthase（iNOS） and arginase 1（Arg1）protein levels. Results The mRNA levels of IL-6，IL-1β and TNF-α in LPS group was increased by（7083 ± 432.5），（3106 ± 104.3） and（108.0±47.58） folds of that in the control group，respectively（P<0.05）；and the mRNA levels of IL-6，IL-1β and TNF-α in cells treated with galanin decreased by（1.2±0.2），（0.3±0.08） and（19±1.3） folds，respectively，as compared with LPS group（P<0.05）；Relative level of iNOS protein in LPS group increased by（19.5±1.964） folds compared with that of the control group，and relative level of Arg1 protein in LPS group was decreased by（1.6±0.3） folds compared with that of the control group；After galanin treatment， iNOS protein level decreased by（1.7±0.32） folds and Arg1 protein increased by （2.31±0.12） folds lower or greater than that treated with LPS alone（P<0.05）. Conclusions Galanin exhibits a significant inhibitory effect on proinflammatory response induced by LPS in mouse Raw264.7macrophage in vitro.

Key words: RAW264.7 macrophage cell line, Galanin, Cytokines, Arginase 1, In vitro