uPA and HGF expression in cells isolated from damaged muscle of WT mice. Cells were isolated from damaged muscle of WT mice and sorted into Mac-1⁺ and Mac-1⁻ cell populations using a magnetic sorting method. Real-time PCR indicated that Mac-1⁺ cells expressed higher levels of uPA and HGF than Mac-1⁻ cells. Bars represent mean ± SE; n = 3 per group. *Mean value significantly different from that for Mac-1⁻ cells (P < .05).