Matrix metalloproteinases contribute to the mast cell-induced contraction of tenocyte populated collagen matrices. Tenocytes embedded in collagen matrices were stimulated with mast cell sonicate (MCS) for the indicated times and RNA was extracted. The quantitative polymerase chain reaction analysis shows the mRNA expression of matrix metalloproteinases MMP1 (A) and MMP7 (B) by tenocytes in response to MCS. Data represent mean ± standard error of the mean of at least three separate experiments, each run in triplicate (Student’s t test, *P <0.025 relative to control). (C) A pan-MMP inhibitor (batimastat) added to the collagen gel inhibited contraction of the collagen matrix in response to MCS in a concentration-dependent and time-dependent manner (P <0.001 for effects of both time and treatment).