FIG. 3.

Gelatin zymography for monomeric MMP-9. Panel A shows representative zymograms of homogenized upper genital tract tissues from infected and uninfected C57BL/6 (top) and C3H/HeN (bottom) mice at various days postinfection. Both the 92-kDa latent and 88-kDa active forms have gelatinolytic activity on zymography (as labeled with arrows). The approximate predicted molecular mass of murine monomer MMP-9 at 105 kDa is also labeled (arrows). Abbreviations: Std, recombinant human MMP-9 standards. Panel B shows the results of gelatin zymography relative to total monomer MMP-9 in upper genital tract homogenates. The top half of panel B represents the composite zymography results for infected mice, whereas the bottom half of panel B represents the same for uninfected controls followed in parallel with the infected mice. The black and gray bars represent the mean monomer MMP-9 gelatinolytic activity for tissues derived from C57BL/6 and C3H/HeN mice, respectively (six to eight samples per time point; results are composites of three or four experiments), plus or minus the standard deviation for each (error bars) Gelatinolytic activity was significantly elevated in samples derived from infected C3H/HeN mice relative to day 0 and to samples derived from uninfected C3H/HeN mice beginning day 7 postinfection through day 21 and also day 35 (P values varied but were <0.04 by a two-way t test in each case). In C57BL/6 mice, monomer MMP-9 gelatinolytic activity was elevated relative to day 0 beginning on day 7 and remained significantly elevated through day 56 (P < 0.05 in each case). Asterisks indicated significant differences observed between strains at days 7 (P < 0.01), 28, and 56 (P < 0.04 for each).