Efficacy of Calcitonin on Bone Healing in Guinea Pigs

Introduction & Objective: Theoretically, it seems that calcitonin can accelerate the healing process, mainly by decreasing bone resorption, but in the literature, there are lots of controversies. The aim of this study is to evaluate the efficacy of calcitonin on bone healing. Materials & Methods: This experimental double blind study was performed on laboratory animals in 1383 at Shiraz University of medical sciences, Department of orthopaedic surgery. Thirty guinea pigs were divided into three groups of ten. Then, they were operated and drilled in proximal part of both tibias. In group A, after operation, calcitonin (30 IU/kg) was injected intraperitonealy (IP) for 7 days. In group B, the injections were subcutaneous for the same time and dose. Group C was selected as control group. Half of the guinea pigs in each group were sacrificed after 2 weeks (A2, B2, C2) and the others after 4 weeks (A4, B4, C4). Multiple sagittal sections were performed on the tibia. In all groups, the formation of periosteum, cortical and trabecular bones were measured. Collected data were analyzed using Kruskall- Wallis test. Results: In A2 and B2 group, the difference of periosteal formation was significant as compared with the control group (p= 0.009). The difference of periosteal formation was even more significant in A2 (IP injection) than in B2 (subcutaneous injection) group. The difference of cortical and trabecular bone formation in groups A2 B2 were not significant in comparison with the control group during the second and fourth weeks. Conclusion: High dose of systemic calcitonin is effective for the rapid formation of periosteum in the early stage of bone healing