Fig. 5

Sarcolemma strength relies on O-mannosylation of α-DG. A Serum creatine kinase (CK) activity was evaluated in control and Pomt1^skm mice to indirectly assess the extent of sarcolemma damage under baseline conditions and two hours after a downhill treadmill running exercise. Data expressed as mean ± standard deviation. P-values determined by ordinary one-way ANOVA with Tukey’s multiple comparisons test. * = 0.0355; ** < 0.004. B Immunofluorescence of cross-sections of gastrocnemius muscles harvested three days after control or Pomt1^skm mice endured a single bout of isometric and forty eccentric contractions. Muscle from the left leg was used as a contralateral control for the muscle tested on the right leg. Sections were stained with antibodies to detect β-DG (rabbit polyclonal AP83; green), mouse IgG (orange), and DAPI (blue). Images shown at 20X magnification. C Percent of initial force in repeated ex vivo lengthening contractions in extensor digitorum longus (EDL) muscles control (CON) or Pomt1^skm mice. N = 4 / group. Data expressed as mean ± standard deviation. P-values determined by unpaired t-test with Holm-Sidak post-hoc analysis. **** < 0.0005. D In vivo assessment of plantar flexor response, as measured by the torque in response to repeated eccentric contractions in CON or Pomt1.^skm mice. Data expressed as mean ± standard deviation. N = 5 / group. Data expressed as mean ± standard deviation. P-values determined by unpaired t-test with Holm-Sidak post-hoc analysis. * < 0.05; *** < 0.001