Figure 6.

Proliferation of BM-derived and resident muscle cells is decreased in adult p75KO tissue transplanted with young p75KO but not young WT BM cells. Representative ×20 confocal microscopy images of HL muscle tissue from 2 chimeric BMT models: young WT/GFP⁺ BMT to adult p75KO and young p75KO/GFP⁺ BMT to adult p75KO mice 28 d after HLI surgery. Representative images of young WT (A) and young p75KO (D) BMT GFP⁺ cells (green) identified in adult p75KO tissue; Ki67⁺ (red) cells in adult p75 mice transplanted with young WT (B) and p75KO (E) BM cells. C, F) Triple-overlaid images of GFP⁺/Ki67⁺/TO-PRO-3⁺ immunostained cells. White arrowheads show BM-derived cells transplanted from GFP⁺ young WT and p75KO donor mice that are also proliferative (Ki67⁺) in adult p75KO HLI tissue. These are also shown as double-positive yellow-colored cells in the overlaid images. White circles represent GFP⁻ and Ki67⁺, proliferative, resident adult p75KO cells (magenta) in HLI tissue.