FIGURE 1.

AT2R expression is increased during skeletal muscle regeneration and satellite cell differentiation. A, the number of regenerating myofibers (myofibers with centralized nuclei) after CTX injection (top panel with representative pictures). Gastrocnemius muscle was injected with CTX on day (d) 0, and muscles were harvested on days 3, 5, and 7. Paraffin sections were prepared from the middle of the gastrocnemius muscle, and the regenerating myofiber number was quantified per section. For qRT-PCR analysis (bottom panel), RNA was extracted from whole gastrocnemius muscles. B, expression of AT2R during primary satellite cell (SC) and C2C12 myoblast differentiation. Primary satellite cells were collected from C57BL/6 mouse hind limb muscles and cultured in proliferation medium. After cells reached confluence (day 0), the medium was switched to differentiation medium, and cells were harvested after 1, 2, and 3 days. C2C12 myoblasts were cultured and harvested under the same conditions as primary satellite cells. AT2R, myogenin, and desmin expression was analyzed by immunoblotting. C, qRT-PCR analysis of AT2R, myogenin, and eMyHC under the same conditions as in B. Data are mean ± S.E. (n = 5). *, p < 0.05; **, p < 0.01 compared with day 0.