Figure 3.

Recombinant IGF-I protein injection increases the contribution of BMDCs to skeletal muscle. (a) Saline (control) or recombinant IGF-I protein (1, 5, and 10 μg) was injected into the TA muscles of mice that had received a BMT 8 wk earlier, and muscles were harvested 4 wk after protein injection. Immunofluorescence images of transverse sections of muscles injected with saline or 5 μg IGF-I and stained for laminin only (top) or for GFP and laminin (bottom) are shown. Arrows indicate GFP⁺ myofibers. (b) The total numbers of GFP⁺ myofibers per transverse section are shown (± SEM). Asterisk indicates values that were significantly different from the control (P < 0.05). P value was determined with a t test. Significance of the values from the dose–response trendline was calculated by using the Pearson correlation coefficient (P < 0.01). Bars, 50 μm.