Immunoexpression of IGF-I/IGF-II in Bone Repair After Treatment with Bisphosphonate

Objectives: To histologically evaluate bone repair in rats associated with autogenous grafting and expression of IGF-I and IGF-II after systemic administration of alendronate sodium (ALN).
Methods: In total, 120 rats were randomly divided into four groups: Group C (control), Group OA (autogenous bone), Group B (bisphosphonates) and Group OA-B (autogenous bone + bisphosphonates). Groups B and OA-B received ALN 0.01 mg/kg subcutaneously on alternate days for 4 weeks. Groups C and OA received saline solution. Critical 5 mm defects were created, which were filled with blood clot in Groups C and B, and with autogenous bone in Groups OA and OA-B. The animals were euthanized at 15 or 30 days postoperatively. Histological analysis and immunohistochemistry of IGF-I and II proteins was performed.
Results: Groups C and B revealed healing predominantly characterized by connective tissue. In Groups OA and OA-B, healing of connective tissue with osteoblastic activity and neoformation of compact bone was observed. Expression of IGF-I was present in all specimens, which was more pronounced in Groups OA and OA-B 15 days postoperatively. The expression of IGF-II was only observed in groups OA and OA-B, with greater intensity in the group OA-B 30 days postoperatively.
Conclusions: In this study, ALN 0.01 mg/kg did not interfere with bone repair and the expression of IGF-I and slight staining of IGF-II was observed in groups OA and OA-B. The systemic use of ALN 0.01 mg/kg on alternate days 4 days prior to surgery did not interfere with bone repair.