FIGURE 2.

Calcium homeostasis characterization of adult, aged, and treated FDB fibers. (A) Resting calcium concentration measured in ADULT, AGED + vehicle, AGED + branched-chain amino acids (AGED + BCAAs), AGED + branched-chain amino acids +2 L-alanine (AGED + BCAAs + 2ALA), and AGED + branched-chain amino acids + L-alanyl-L-alanine (AGED + BCAAs + Di-ALA). A statistically significant difference was found by unpaired Student’s t-test for AGED + vehicle vs. ADULT (*p < 0.0001). A statistically significant difference was found among AGED mice groups by one-way ANOVA (F = 14.87; p < 0.0001). Dunnett’s post hoc test, used to compare each mixture-treated group to the vehicle group, is as follows: °vs. AGED + vehicle (p < 0.0001). Values are expressed as the mean ± SEM of the number of fibers analyzed (indicated in brackets over the bars) derived from a number of 6/7 mice in each group. (B) Representative traces of increased Ca²⁺ entry in store-depleted thapsigargin-treated muscle fibers after the addition of extracellular calcium (see SOCE protocol described in Materials and methods) in ADULT and AGED + vehicle. (C) Amplitude values of [Ca²⁺]i observed with the SOCE protocol in ADULT, AGED + vehicle, AGED + BCAAs, AGED + BCAAs + 2ALA, and AGED + BCAAs + Di-ALA. A statistically significant difference was found by unpaired Student’s t-test for AGED + vehicle vs. ADULT (*p < 0.0001). A statistically significant difference was found among AGED mice groups by one-way ANOVA (F = 3.589; p = 0,0318). Dunnett’s post hoc test, used to compare each mixture-treated group to the vehicle group, is as follows: °vs. AGED + vehicle (p < 0.035). Values are expressed as the mean ± SEM of the number of fibers analyzed (indicated in brackets over the bars) derived from a number of 3 mice in each group. The recovery score toward the ADULT value, calculated for each treated group, is indicated above the bars.