Calvarial bone defects in ovariectomized rats treated with mesenchymal stem cells and demineralized freeze-dried bone allografts.

The aim of the study was to investigate the ability of a combination of bone marrow mesenchymal stem cells (BM-MSCs) with and without demineralized freeze-dried bone allografts (DFDBAs) to induce bone regeneration in calvarial defects in ovariectomized rats. Critical size defects were filled with a combination of demineralized freeze-dried bone allografts and bone marrow mesenchymalstem cells(BM-MSCs) or BM-MSCs alone. Eight weeks after calvarial surgery, the rats were sacrificed. The samples were analyzed histologically and immunohistochemically. No difference was observed in vascularization between groups C1 (animals with cranial defect only, control group) and O1 (animals with cranial defect only, ovariectomy group). Intramembranous ossification was observed at a limited level in groups C2 (animals with cranial defect with MSCs, control group) and O2 (animals with cranial defect with MSCs, ovariectomy group) compared to C1 and O1. In group C3 (animals with demineralized freeze-dried bone allografts with MSCs, control group), the fibrous structures of the matrix became compact as a result of a bone graft having been placed in the cavity, but in group O3 (animals with demineralized freeze-dried bone allografts with MSCs, ovariectomy group), the fibrous tissue was poorly distributed between the bone grafts for the most parts. We conclude that the insertion of BM-MSCs enhances bone healing; however, the DFDBA/BM-MSC combination has little effect on overcoming impaired bone formation in ovariectomized rats.