Fig 1. Histology of P448Lneo- and C57 diaphragm at the ages of 6–8 weeks, 6 months, 8 months, 10 months and 12 months.

(A) H&E staining. Of note is the increasing amount of extracellular matrix and infiltration of mononuclear cells at 6 months of age in the P448Lneo- mutant mice. (B) Masson’s trichrome staining. Blue staining indicates increasing amount of collagen connective tissue. Significant collagen connective tissue replacement can be seen at 6 months of age in P448Lneo- mutant diaphragm and increasing through 12 months of age. Little to no blue staining is present in C57 diaphragm up through 12 months of age. Representative of a minimum of 3 mice per age group. All samples shown at 20X magnification. Yellow bar equal to 200μm.