Time course of joint wound healing parameters is abnormal within blood-exposed joint synovium in mice with hemophilia in comparison with hemostatically normal mice. (A) Iron staining in joint wounds from WT and FIX^−/− mice. Iron released from degraded erythrocytes in the ferric (+3) state stains blue, heaviest areas of staining within joints of all mice were graded 0 to 3+, and the means and standard deviation for all cohorts of mice are plotted. Iron in hemoglobin is in the ferrous (+2) state so that intact red blood cells are not stained. Plots of the data for both groups of WT mice overlap completely. Points that are significantly different from “WT + Blood” are indicated by “*.” Points that are significantly different from “WT + NS” are indicated by “#.” Markers of significance are used as follows: **P < .01, ****P < .0001, ^##P < .01, ^####P < .0001. (B) Macrophage infiltration and residence in joint wounds from WT and FIX^−/− mice. Macrophage infiltrate was identified by immunostaining for CD68 and scored as described in the supplemental Methods. Points that are significantly different from “WT + Blood” are indicated by “*.” Points that are significantly different from “WT + NS” are indicated by “#.” Markers of significance are used as follows: *P < .05, ****P < .0001, ^#P < .05, ^##P < .01, ^####P < .0001. (C) Angiogenesis in joint wounds in WT and FIX^−/− mice. Vascular endothelial cells were identified by staining for VWF with a rabbit polyclonal primary antibody (Abcam, Cambridge, MA). The counts are expressed per high-powered (×40) field. Points that are significantly different from “WT + Blood” are indicated by “*.” Points that are significantly different from “WT + NS” are indicated by “#.” Markers of significance are used as follows: *P < .05, ****P < .0001, ^##P < .01, ^####P < .0001.