Objective:To investigate the effect of 630 nm LED irradiation on the polarization and function of murine M1-macrophages both in vitro and in vivo.Methods:Murine macrophage cell line RAW264.7 and primary peritoneal macrophages were irradiated with 630 nm LED(at a power density of 8 mW/cm2)either before or after the induction of M1-polarization by lipopolysaccharide(LPS)and interferon-γ(IFN-γ).Cell viabilities were measured by CCK-8 assay.Levels of surface activation/costimulatory molecules CD80&CD86 were determined by flow cytometry,and expressions of proinflammatory cytokines including tumor necrosis factor-α(TNF-α),interleukin-6(IL-6)&interleukin-1β(IL-1β)were analyzed by quantitative real-time PCR(RT-qPCR)and/or enzyme-linked immunosorbent assay(ELISA).Results:Despite no effect on cell viabilities,630 nm LED irradiation,either before or after the induction of M1-polarization by LPS and IFN-γ,not only significantly reduced surface expressions of CD80 and CD86 on RAW264.7 cells,but also hampered their mRNA exprssion and productions of pro-inflammatory cytokines TNF-α,IL-6 and IL-1β(P<0.05).Moreover,pretreating mice with 630 nm LED followed by in vitro LED irradiation of cells repressed the ability of primary murine peritoneal macrophages to secrete TNF-α and IL-6 upon activation by LPS and IFN-γ in vitro as well(P<0.05).Conclusion:630 nm LED irradiation blunts the M1 polarization and pro-inflammatory cytokine production of murine macrophages,which may provide new therapeutic strategy for the clinical treatment of M1 macrophage-mediated inflammatory diseases.
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