Fig. 2

Matrix metalloproteinase (MMP)-1 and -2 protein levels increase in flexor digitorum muscles with high repetition negligible force (HRNF) task. a Representative Western blot of muscle homogenates probed with anti-MMP-1. An immunoreactive band at the expected molecular weight of 54 kDa was detected. β-actin was used as a loading control (42 kDa). b Densitometric analysis of the MMP-1 band from three replicate Western blots were normalized to β-actin levels and documents significant increases relative to food restricted control (FRC) rats after 3 and 6 weeks of the HRNF task and between 3 and 6 weeks of the task. c Representative Western blot of muscle homogenates probed with anti-MMP-2. Bands are detected at the expected molecular weights for the latent (72 kDa) and active (66 kDa) forms. d, e Densitometric analyses of the MMP-2 protein bands (72 and 66 kDa) from three replicate Western blots after normalization to β-actin levels show that only the active form is increased. *p < 0.05, **p < 0.01, compared to FRC rats; ns = not significant