Synergistic mobilization of normal mice treated with G-CSF and a single injection of Ptx. Normal (left 3 bars) and MMP9-/-(right 3 bars) mice were treated with G-CSF alone (100 μg/kg twice daily for 3 days), with Ptx alone (one injection at 100 ng/mouse), or with both (same doses, black bars). Blood was collected on day 4 and cultured for CFU-C levels. The synergy noted in normal animals was practically abolished in MMP9-/-mice (black bar on the far right).