FIGURE 3.

The AT2R agonist potentiates skeletal muscle regeneration in vivo. A, experimental model. CTX was injected, and AT2R antagonist CGP42112 infusion (10 μg/kg/min) was started on day 0. Gastrocnemius muscles were collected on days 3, 5, and 7. For H&E staining, paraffin sections were prepared from the middle of the gastrocnemius muscle. For qRT-PCR analysis, RNA was extracted from whole gastrocnemius muscle. B, number of regenerating myofibers (myofibers with centralized nuclei) after CTX injection and sham (S) or CGP42112 (CG) infusion on day 5. The number of regenerating myofibers is shown per section. C, Cross sectional area (CSA) of regenerating myofibers after CTX injection and CGP infusion on day 5. D, the same sections as in C were stained for skeletal muscle slow and fast myosin, and the size of the regenerating myofibers was quantified. E, the number of regenerating myofibers was analyzed on the same sections as in B and categorized on the basis of the number of centralized nuclei in each myofiber. F and G, qRT-PCR analysis of myogenin (F) and eMyHC (G) in the gastrocnemius muscle after CTX injection and CGP infusion on days 0, 3, 5, and 7. Data are mean ± S.E. (n = 5–6). *, p < 0.05; ns, not significant.