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. 2009 Apr 28;18(14):2584–2598. doi: 10.1093/hmg/ddp191

Figure 3.

Figure 3.

Genetic deletion of MMP-9 inhibits AP-1 and NF-κB and reduces the serum level of CK and improves muscle structure in mdx mice. (A) Representative immunoblots presented here demonstrate reduced levels of MMP-9 and MMP-2 protein in diaphragm and TA muscle of mdx;Mmp9+/− (n = 3), mdx;Mmp9−/− (n = 3) compared with littermate mdx;Mmp9+/+ (n = 4) mice. (B) Representative EMSA gels from two independent experiments presented here demonstrate that the activation of AP-1 and NF-κB is significantly reduced in TA muscle of 8-week-old mdx;Mmp9+/− and mdx/Mmp9−/− mice compared with littermate mdx;Mmp9+/+ mice. (C) Serum level of CK measured using a commercially available kit (Stanbio Laboratory, TX, USA) in 8-week-old littermate WT (n = 4), mdx;Mmp9+/+ (n = 6), mdx;Mmp9+/− (n = 7) and mdx;Mmp9+/+ (n = 6) suggest that heterozygous and homozygous deletion of Mmp9 gene significantly reduces the serum level of CK in mdx mice. Data presented are mean ± SD from two independent experiments. *P < 0.01 values significantly different from littermate mdx;Mmp9+/+ mice. (D) Frozen cross-sections made from diaphragm and TA muscle of 7-week-old WT;Mmp9+/+ (n = 3), mdx;Mmp9+/+ (n = 4), mdx;Mmp9+/− (n = 7) and mdx;Mmp9−/− (n = 6) mice were stained with H&E and photomicrograph. Scale bar: 50 µm. Data presented here demonstrate that the deletion of Mmp9 gene in mdx mice improves skeletal muscle structure.