ABSTRACT
Objective To elaborate the role of hepatic inherent macrophages and monocyte-derived macrophages in acute liver injury.Methods A model of acute liver injury in mice was induced via intraperitoneally injection of CCl 4 .Af-ter CCl4 injection, analysis of the expression of CD45, F4/80, Ly6C and CD11b on the hepatic macrophage surface was performed by flow cytometry at 24, 48 and 72 h before the hepatic inherent macrophages (CD45+F4/80hi) and monocyte-de-rived macrophages ( CD45+F4/80 lo ) were sorted at the same time .The relative expression of cytokines in the two popula-tions of macrophages was detected by qRT-PCR.Results Compared with control , the number of total F4/80 +cells in the liver was markedly increased after CCl 4 injection, especially at 72 h.The number of CD45+F4/80lo cells increased signifi-cantly after CCl4 injection 24 h.The mRNA levels of MCP-1, TNF-α, TGF-β1, matrix metalloproteinase(MMP)-12 and MMP-13 were elevated significantly both in F 4/80 hi and F4/80 lo macrophages .IL-12βand IL-6 mRNA levels increased significantly only in F4/80hi macrophages, while the level of MMP-9 mRNA increased markedly only in F4/80lo macropha-ges.When compared with F4/80lo macrophages, MCP-1 and MMP-12 mRNA levels were elevated significantly , while the level of TNF-αmRNA decreased significantly in F4/80hi macrophages.Conclusion In acute liver injury, hepatic inherent macrophages and monocyte-derived macrophages both express inflammatory cytokines , promoting inflammation response and leading to liver damage .The ability to recruit inflammatory monocytes into the liver is much stronger ,the expression of in-flammatory cytokines ( IL-12βand IL-6 ) and MMP-12 is higher , but the expression of inflammatory cytokines ( TNF-α) MMP-9 is lower in hepatic inherent macrophages than in monocyte-derived macrophages .