Fig. 3. Severe muscle degeneration in gxi double-mutant mice. Masson trichrome staining shows that muscle from integrin 7 mutants (Itg7^–/–) appears indistinguishable from the wild type in young mice (aged 3 weeks). Muscle from -sarcoglycan null mice (gsg^–/–) displays focal degeneration, seen as blue areas. This regional fibrosis is often immediately adjacent to normal appearing regions of muscle (surrounding red). In contrast, double-mutant mouse muscle (gxi) has widespread degeneration affecting all parts of the muscle. At this low magnification view, fibrosis is seen interspersed throughout gxi muscle (note blue areas in lower right panel). Bar, 200 µm.