Fig. 7. Cell-specific deletion of Cx43 delays TA regeneration. (A) Levels of Cx43 were measured by western blot analysis in TA homogenates (100 µg of protein) obtained at day (D) 3, 7, 10 or 14 of regeneration after BaCl₂ treatment. Muscles were from pI-pC-treated Cx43^fl/fl, Mx-cre mice (fl/fl, Mx-cre) and pI-pC-treated Cx43^fl/fl mice (fl/fl). The non-phosphorylated (NP) and phosphorylated (P) forms of Cx43 are indicated. (B) Hematoxylin and Eosin-stained cross sections of TAs from pI-pC-treated Cx43^fl/fl and pI-pC-treated Cx43^fl/fl, Mx-cre mice after 7, 10 or 14 days post BaCl₂ administration (D7 PI, D10 PI, or D14 PI, respectively). A small group of damaged cells is present in the 14 days PI (D14 PI) sample, (indicated by a dashed rectangle). Scale bar: 100 µm. (C) At 7 days PI (D7 PI), X-gal stained nuclei were observed in sections of TAs from pI-pC-treated Cx43^fl/fl, Mx-cre mice but not in TAs from pI-pC-treated Cx43^fl/fl mice. Scale bar: 100 µm. (D) Co-localization of specific cell markers and X-gal staining in regenerating TAs from pI-pC-treated Cx43^fl/fl, Mx-cre mice. These panels showed co-localization of X-gal staining with myogenin (Myo) at D5 PI and desmin, CD14 or von Willebrand factor (VWF) at D3 PI. Arrows indicate co-localization sites. Scale bar: 12 µm for Myo, Desmin and CD14 panels and 20 µm for VWF panel. (E) Relative levels of myogenin (Myo) were measured by western blot analysis in samples (100 µg of protein) of TA homogeneates obtained from pI-pC-treated Cx43^fl/fl or pI-pC-treated Cx43^fl/fl, Mx-cre mice at different days (3, 5, 7, 10, and 14) PI.