Figure 5

Continuous PTH recruits increased numbers of macrophages in bone marrow and this is ablated in MCP-1^−/− mice. (A) Two weeks of cPTH infusion increased the osteomac population in WT mice compared to vehicle-infused WT mice. MCP-1^−/− mice showed fewer F4/80 positive cells in both vehicle and PTH-infused groups. Immunohistochemistry of tibial sections with F4/80 (magnification 60X). (B) Sections of WT and MCP-1^−/− mice immunostained for Mac-3 and quantitation of stained cells. (C) CD68 immunostained sections of tibiae of WT and MCP-1^−/− mice infused with cPTH or vehicle and quantitation of stained cells. There is a modest expression of Mac-3 and CD68 in MCP-1 null mice, with and without cPTH infusion (magnification 60X) and no stimulation with PTH. IgG was used as negative control for each stained section. *p < 0.05, ***p < 0.001 compared to vehicle-infused WT mice.