Fig. 4

Immunohistochemical analysis showing Rad and Rem1 expression (brown staining) in nonunion fibrous tissue, as visualized using antibodies to a Rad at post-fracture days 14 and c 21, and b Rem1 at post-fracture days 14 and d 21. Bars, 100 μm. The fracture gap was covered by fibrous tissue filled with fibroblast-like spindle cells (red arrows), which exhibited positive Rad and Rem1 staining.