FIGURE 5.

Insl6 overexpression promotes muscle regeneration in old mice. Approximately 10 μl of CTX solution (10 μm) was injected in 4 different positions on GA muscle. At 48 h after the injury, 5 × 10⁹ total pfu of Adeno-βgal or Adeno-Insl6 was also injected into 4 regions of GA muscle. A, representative image of H&E-stained GA muscle cross-sections at day 7 after the cardiotoxin injection (n = 4–6 in each group). Histological analysis of muscle regeneration was assessed by counting nascent myofibers and measuring myofiber cross-section area at day 7 post-injury. Data are expressed as a percentage relative to the mean value for the Adeno-βgal-treated group. B, in vivo TUNEL staining was performed, and positive cells are quantified in histological sections. Data are presented as the mean ± S.E. *, p < 0.05.