Increased muscle fibrosis and inflammation in <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice.

<p><b>(a)</b> Representative H&E-stained gastrocnemius and triceps from 34 weeks old male wild type and <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice. Scale bar: 100 μm <b>(b)</b> Percentage of pathological area quantified on H&E stained sections. A significant increase (<i>P</i><0.0001) in pathological tissue area was found in <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> gastrocnemius and triceps relative to wild type muscles. Pathology was more pronounced (<i>P</i><0.0001) in gastrocnemius than in triceps of <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice. <b>(c)</b> Representative Sirius red-stained gastrocnemius and triceps from 34 weeks old male wild type and <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice. Scale bar: 100 μm. (<b>d</b>) Percentage of collagen quantified on Sirius red stained sections. A significant increase in Sirius red positive area was found in <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> gastrocnemius and triceps relative to wild type muscles. <b>(e)</b> Gene expression of fibrotic markers measured by qPCR. Gastrocnemius of <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice expressed significantly higher levels of <i>Ctgf</i>, <i>Col1a1</i> and <i>Col3a1</i> (<i>P</i><0.01) when compared to <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> triceps, diaphragm and wild type muscles. <i>Col1a1</i>and <i>Col3a1</i> levels (<i>P</i><0.05) were significantly higher in triceps muscle of <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice than in wild type and <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> diaphragm. <b>(f)</b> Gene expression of inflammatory markers measured by qPCR. A significant upregulation of <i>Cd68</i> transcript (<i>P</i><0.01) was found in gastrocnemius of <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice when compared to wild type mice and <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> diaphragm. <i>Lgals3</i> levels were significantly higher (<i>P</i><0.01) in <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> gastrocnemius and triceps when compared to wild type and <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> diaphragm. <i>Lgals3</i> levels of gastrocnemius exceeded (<i>P</i><0.01) those of the triceps in <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> mice. Data were normalized to <i>Gapdh</i>. Gas, gastrocnemius; Tri, triceps and Dia, diaphragm. * Indicates a significant difference from muscle type-matched wild type (WT) controls. # Indicates a significant difference from <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> gastrocnemius muscle. $ Indicates a significant difference from <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> triceps. Error bars represent ± SD, n = 5 (functionally challenged males per group). For Sirius red analysis: n = 5 functionally challenged wild type males and n = 4 functionally challenged <i>dy</i>^<i>2J</i><i>/dy</i>^<i>2J</i> males.