Figure 5.

Effect of testosterone supplementation on muscle regeneration in young skeletal muscle 4 days postinjury. Representative image showing regenerating fibers positive for emb-MyHC (red) and for laminin (green) (A). Testosterone treatment increases the cross-sectional area (B) of emb-MyHC⁺ muscle fibers 4 days postinjury, when compared with Cast mice, as also corroborated by the right shift showed by the distribution by frequency classes of fiber diameter (C) (p value for chi-square analysis <.001). The number of emb-MyHC⁺ muscle fibers when normalized for the regenerating area did not differ significantly between testosterone-treated orchiectomized mice and Sham or Cast mice (D). Results are means ± SEM (n = 4/group). *p < .05; **p < .01. Representative critical values for t test statistic: Figure B, Sham versus Cast: t = 4.590; df = 6.