Fig. 2

RyR1-Rec mice show progressive reduction in muscle and body weights and in muscle strength. a Body weight and b Muscle strength estimated as a function of time after recombination using a grip test in which the time the animals can hang upside down on a grid up to 5 min (300 s). Data are mean ± SEM of n = 10-15 animals in each group, * p < 0.05 Student’s t test with Holm-Sidack’s correction for multiple comparisons. c Recording of the tension developed by gastrocnemius during a 6 min electrostimulation protocol at 2 Hz. Longitudinal study of the same animals (CRTL, left panel, and RyR1-Rec, right panel) at different times after recombination, 30 days (D30), 60 days (D60) and 90 days (D90). Data are mean ± SEM of n = 8 CRTL and n = 6 RyR1-Rec animals. d Gastrocnemius muscle volume for CTRL (n = 8) and RyR1-Rec (n = 6) mice at 30, 60 and 90 days after recombination. Data are mean ± SEM. Statistical analysis: post hoc LSD Fisher test following two-way repeated measures ANOVA, *significantly different from CTRL at the same time, ^asignificantly different from D30 in the same group, ^bsignificantly different from D60 in the same group. e Maximal specific twitch tension (maximal twitch tension normalized to the gastrocnemius volume). Statistical analysis: post hoc LSD Fisher test following two-way repeated measures ANOVA *significantly different from CTRL at the same time, ^asignificantly different from D30 in the same group, ^bsignificantly different from D60 in the same group