(A) Differences in TA muscle masses due to estradiol treatment depend on the number of injuries (interaction effect; p<0.006). (B) The total number of satellite cells in TA muscles, quantified by FACS as lineage negative;VCAM, alpha7 double-positive cells, is greater in ovariectomized mice treated with estradiol (main effect of treatment; p<0.001). (C) The total number of satellite cells normalized to muscle mass is greater in ovariectomized mice treated with estradiol (main effect of treatment; p,0.001) and lower with injury (main effect of time; p=0.002). Data was derived from the TA muscles of Ovx+E2 and Ovx+Placebo mice that were not injured, or from TA muscles that had recovered from one or three BaCl2-induced injuries. Sample size per group, n=7-16 mice. Ovx; ovariectomized, E2; 17β-estradiol. Values are presented as mean±SD. For A, following the significant interaction pairwise post-hoc results are indicated by: *Significantly different from Ovx+E2 at given time point; #Significantly different from Uninjured within treatment group. Main effects of two-way ANOVAs are indicated above each set of bars in B and C.