Figure 6. Fiber type shift seen in skeletal muscle of Myoz1 KO mice.
(A) Immunofluorescence histochemistry for type IIa fibers using SC-71 antibody (green, FITC-labeled lectin). (B) An increase of 56.2% was found in the number of type IIa fibers/mm2 in the gastrocnemius of Myoz1 KO mice compared with WT littermates (n = 6–7 animals). (C) The cross-sectional area of type IIa fibers remained unchanged. (D) SDH staining of gastrocnemius showed an increase of SDH-positive fibers in Myoz1 KO mice compared with WT controls. (E) Quantification of SDH-positive fibers shows a 2.58-fold increase in Myoz1 KO mice compared with WT (n = 4 mice per group). (F) Immunofluorescence histochemistry for type IIb fibers using BF-F3 antibody (green, FITC-labeled lectin). (G) The number of type IIb fibers/mm2 increased in Myoz1 KO mice. (H) A reduction was found in the cross-sectional area of type IIb fibers (n = 105–178 cells). (I) Immunofluorescence histochemistry for type I fibers using NOQ7.5.4D antibody. (J) The number of type I fibers/mm2 increased in the soleus of Myoz1 KO mice compared with WT littermates (n = 4–6 mice). (K) Cross-sectional area of type I fibers increased in the soleus in Myoz1 KO mice compared with WT controls (n = 143–260 fibers). Scale bars: 100 μm. *P < 0.05, †P < 0.01, ‡P < 0.001.