Figure 2.

H2A.Z loss in muscle fibers leads to muscle alterations at 12-month-old. (A) Representative image of hematoxylin phloxine saffron (upper panel), laminin/Dapi staining (middle panel) and Sirius Red (lower panel) in transversal sections of TA muscle (scale bar = 50 μm). (B) Quantification of cross-sectional area (CSA) of the whole TA with the measure of tissue surface in μm² (C). The density (D), and the fiber number per tissue. (E) The data are shown as box-and-whisker plot with tukey style. Statistical analysis was performed using Mann–Whitney test. (*P < 0.05, **P < 0.01, ns: not significant, n = 5 per genotype). (F) Representative immunoblots for phosphorylated and total proteins of PKB/Akt in H2A.Z mdKO and CTL TA muscles. Tubulin was shown as loading control. (G) Densitometry quantification of phosphorylated bands relative to the total bands. Error bars are the SEM calculated from four independent CTL and 5 H2A.Z mdKO. Statistical analysis was performed using Mann–Whitney test. (*P < 0.05; ns: not significant). (H) Percentage of centronucleated fibers. (I) Relative mRNA expression of the regenerative marker MYH8. The data are shown as box-and-whisker plot with tukey style. Statistical analysis was performed using Mann–Whitney test (*P < 0.05, **P < 0.01, ns: not significant, n = 5 per genotype). (J) Quantification of F4/80+ cells/mm² in the CTL and H2A.Z mdKO TA muscles. Error bars are the SEM calculated from 3 mice per group. Statistical analysis was performed using unpaired t test (*P < 0.05). (K) Representative images of IgG immunostaining in CTL and H2A.Z mdKO TA muscles. (L) Protocol of exercise to exhaustion test on the treadmill. (M) Percentage of running population on the treadmill by the distance of CTL (n = 13) and H2A.Z mdKO (n = 20) mice. The Log-rank test was performed to compare the two mouse groups (***P < 0.0001).