Increased collagen deposition in the skeletal muscles of Sigmar1−/− mice. A–E: Left panels: Representative images of picro-sirius red (PSR) stained histologic cross-sections of gastrocnemius (Gastro; A), quadriceps (Quad; B), tibialis anterior (TA; C), soleus (Sol; D), and extensor digitorum longus (EDL; E) muscle sections from wild-type (Wt) and Sigmar1−/− mice. Representative images are from 12 high-magnification microscopic fields (×20) per mice muscle sections for Gastro, Quad, and TA muscles, and 5 high-magnification microscopic fields (×20) for Sol and EDL muscles per mice. A–E: Right panels: Box plots represent percentage collagen content measured in respect to PSR stained whole muscle cross-section areas in Wt and Sigmar1−/− mice skeletal muscles. Quantifications of percentage collagen areas were performed on 12 high-magnification microscopic fields (×20) per mice muscle sections for Gastro, Quad, and TA muscles, and on 5 high-magnification microscopic fields (×20) for Sol and EDL muscles per mice. P values indicate statistical significance between Wt and Sigmar1−/− mice. Boxes represent interquartile ranges, lines represent medians, and whiskers represent ranges. P values were determined by unpaired t-test. n = 4 to 5 individual mice at the age of 9 to 10 months per genotype per muscle (A–E). ∗∗P < 0.01, ∗∗∗P < 0.001. Scale bars = 50 μm (A–E).