Figure 3.

MMP-8 is necessary for PMN migration through collagen gels. Migration assays of WT PMNs and MMP-8^−/− PMNs across rat-tail collagen type 1 gels in vitro were performed. PMNs that had migrated through the gels onto the 0.4-μm polycarbonate membrane (113 mm² surface area) were counted under a fluorescent microscope at 4 h and 24 h. Analysis of the data from five experiments (expressed as mean±sem) showed that WT PMNs were able to penetrate collagen gels in significantly greater numbers at 4 h (*, P=0.03) and 24 h (#, P<0.0001) compared with MMP8^−/− PMNs.