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. 2013 Jun 12;305(5):C529–C538. doi: 10.1152/ajpcell.00051.2013

Fig. 1.

Fig. 1.

Matrix metalloproteinase (MMP) levels in acute and chronic muscle damage. A–C: results from quantitative RT-PCR show different patterns of Mmp2, Mmp9, and Mmp13 expression during repair following cardiotoxin (CTX) injection. *Significantly different (P < 0.05, by 1-way ANOVA followed by Bonferroni's post hoc analysis) from no damage (day 0). D: elevation of Mmp2, Mmp9, and Mmp13 expression in muscles from mdx compared with C57BL/6 (C57) mice (dashed line). *P < 0.05, mdx vs. C57 (by unpaired t-test). E: collagen zymography showing activity of MMP-2, MMP-9, and MMP-13. Activity follows a time course similar to that of transcriptional changes during repair following CTX injection. Samples consist of 15 μg of protein from zymogen extracts of CTX-injected and noninjected (ND) muscles. F: immunoblots of MMP-13 in zymogen extracts of regenerating muscle. Results further confirm that the 52-kDa band is MMP-13. G: immunoblots of MMP-2, MMP-9, and MMP-13 in muscles from mdx and C57 mice. H: results from G showing significantly higher MMP-9 and MMP-13 levels in mdx muscles than in C57 (dashed line). *P < 0.05, mdx vs. C57 (by unpaired t-test).