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. 2018 Feb 20;27(9):1608–1617. doi: 10.1093/hmg/ddy068

Figure 4.

Figure 4.

Reduction in CSA and contractility in hindlimb muscles of Speg-KO mice (A). Mean (±SE) pCSA of TA preparations, n = 5 for CTRL and n = 5 for KO mice. * indicates a significant difference, P < 0.05. (B) Mean (±SE) TA twitch force. *** indicates a significant difference between CTRL and KO means, P < 0.001. Number of muscles same as panel A. (C) Mean (±S.E.M.) TA twitch contraction time (CT). Number of muscles same as (A). (D) Mean (±SE) TA twitch half-relaxation time. Number of muscles same as (A). (E) Mean (±SE) TA peak force. *** indicates a significant difference between CTRL and KO means, P < 0.001. Number of muscles same as (A). (F) Mean (±SE) pCSA of EDL and soleus (SOL) muscles. A significant genotype by muscle interaction (P < 0.001) indicated that the absence of SPEG had significantly different effects on EDL versus SOL muscles. * indicates a significant difference from the corresponding CTRL mean, P < 0.05. Means based on 10 EDL CTRL, 6 EDL KO, 8 SOL CTRL and 5 SOL KO muscles. (G) Mean (±SE) peak force of EDL and SOL muscles. A significant genotype by muscle interaction (P < 0.01) indicated that the absence of SPEG had significantly different effects on EDL versus SOL muscles. * indicates a significant difference from the corresponding CTRL mean, P < 0.05. Number of muscles same as panel (F). (H) CSA of skinned TA muscle fibers. Individual CTRL animals are designated by C1–C5 and individual knock-out KO animals by K1–K4. Black points represent individual fibers within an animal, gray circles represent the mean (± SE) value for an animal, and the horizontal lines represent the overall CTRL and KO group means. P-value indicates significant difference between CTRL (N = 37 fibers) and KO (N = 32 fibers) means. (I) Unloaded shortening velocity (Vo) of Ca2+-activated TA fibers. Figure format same as (H). P-value indicates that no significant difference was detected between CTRL (N = 37 fibers) and KO (N = 27 fibers) means. (J) Peak force of Ca2+-activated TA fibers. Figure format same as (H). P-value indicates significant difference between CTRL (N = 37 fibers) and KO (N = 32 fibers) means.