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Fig. 2. Mmp9-/- mice exhibit an accumulation of cartilage
during non-stable fracture healing. (A) SO-FG staining of wild-type (top, +/+)
and Mmp9-/- callus tissues (bottom, -/-) at 10, 14 and 21
days indicates that cartilage persists in the Mmp9-/-
callus up to 21 days. (B) Histomorphometric measurements of total callus and
cartilage volumes in wild-type (n=12) and Mmp9-/-
(n=17) mice at 10 and 14 days. There is a statistically significant
increase in the volume of cartilage in Mmp9-/- calluses
compared with wild-type calluses at 14 days (asterisks, Student's
t-test, P=0.02). Bars represent mean±s.e.m. Scale
bar: 1 mm.