Figure 4

Resorption of whale dentin by early differentiation prosthesis loosening fibroblasts (PLFs) from the intracranially self-stimulated (ICSS) Wistar rat model of aseptic prosthesis loosening. (a) Cemented tibial hemiarthroplasties that were implanted into the left knees of ICSS Wistar rats exhibited radiological signs of loosening (arrows) after 12 weeks of stimulated running in a running wheel. (b) Histological evaluation of the interface tissue between the prosthesis and the bone revealed the presence of loose fibrous tissue with fibroblast-like cells, particularly at sites of bone resorption. (c) and (d) Characterization of rat PLFs that were established from this tissue demonstrated the identity of these cells as fibroblasts in that more than 99% of the cells stained positive with specific antibodies against prolyl-4-hydroxylase (d), whereas there was no staining with antibodies against the monocyte lineage marker CD68 (c). (e) and (f) Culturing the rat PLFs on sperm whale dentine slices for 4 weeks produced clear resorption pits (closed arrowheads). Remains of the PLFs were seen in close contact with the resorption pits (open arrowheads).