Effect of p53 deficiency on collagen remodeling. (A) Collagen content in resolving Tp53^+/+ and Tp53^−/− thrombi at day 12 was determined in histological sections after Picrosirius Red staining; original magnification ×100. Scale bar, 400 μm. Representative images from 5 independent mice from each genotype are shown. Collagen content was quantified as a measure of fibrosis as described in “Methods.” All values represent the mean ± SEM (n = 5 Tp53^+/+ and 5 Tp53^−/−). *P < .05, Tp53^+/+ vs Tp53^−/−. (B) Representative gel images of intrathrombotic MMP-2 and MMP-9 activities in venous thrombus samples from Tp53^+/+ and Tp53^−/− mice as measured by gelatin gel zymography (n = 5 and 4 for Tp53^+/+ and Tp53^−/−, respectively). Gel images were subjected to semiquantitative analysis as described in “Methods.” All values represent the mean ± SEM (n = 4-5 per group). *P < .03, Tp53^+/+ vs Tp53^−/−. (C) Intrathrombotic mRNA expression of MMP-2 and MMP-9 in Tp53^+/+ and Tp53^−/− mice at day 8 was determined by quantitative PCR (qPCR). All values represent the mean ± SEM (n = 4 per group). *P < .03, Tp53^+/+ vs Tp53^−/−.