Figure 3.

Spaceflight increased Ca²⁺ uptake and induced a shift towards a fast phenotype in the TA of male mice. (A) Change in the ratio of Ca²⁺-bound to Ca²⁺-free Indo-1 (405/485 nm emission). (B) AUC was significantly reduced in the flight group, representing increased Ca²⁺ uptake. (C) Representative Western blot images and densitometric analysis of myosin heavy chain (MHC) IIa, IIx, and IIb. (D) Representative Western blot images and analyses of SERCA isoform content and total protein T-nitration and S-nitrosylation. All values are means ± SEM, and Western blot data are presented relative to VIV control. * p < 0.05; ** p < 0.01; **** p < 0.0001; values above bars indicate p-values using a one-way ANOVA with Tukey’s post hoc test (n = 9–10 per group).