Fig. 7. Notexin injection after irradiation restores RF expansion. (A) Experimental design of irradiation and notexin treatments in TA muscles of mdx mice. (1) Irradiation only; (2) notexin treatment only; and (3) notexin treatment 4 weeks after 18 Gy irradiation at 3 weeks of age. IHC, immunohistochemistry. (B) The irradiated TA muscle shows a single RF, in contrast to the untreated control TA muscle and notexin-injected muscles without irradiation (notexin only). A regenerating RF cluster reappears after notexin injection in pre-irradiated muscles (18 Gy + notexin). Bar, 100 µm. (C) The total number of RFs and the maximal number of RFs per cluster in TA muscle after notexin treatment with or without pre-irradiation. *Significant difference (P<0.05) was obtained between control mice treated with 18 Gy irradiation only and the mice treated with notexin after 18 Gy pre-irradiation. Each point is the mean ± s.e.m. of 3-4 muscles per group.