Study On The Effect Of Endogenous And Exogenous Parathyroid Hormone On The Bone Healing Of Extraction Sockets In Mice

Parathyroid hormone is one of Single-chain polypeptide proteins, which is synthetized and secreted by chief cells of the parathyroid glands and molecular weight is 9500U, and containing 84 amino acid. It is one of the most important endocrine regulators concentration and metabolism in extracellular fluid. the current evidence indicates that PTH has a role in both bone formation and bone resorption, suggesting its importance in the process of bone remodeling and restoration. The effects of enhancing bone mass and improving bone quality have been confirmed by many animal experiments and clinical studies, therefore, recombinant human parathyroid hormone (1-34) have been approved to treat the post-menopause female osteoporosis and primarily osteoporosis clinically by the American FDA. In the current study, standard tooth extraction models were built to clarify the effects of endogenous and exogenous PTH on the healing of tooth extraction in mice, and to PTH for the prevention and treatment of alveolar bone loss after tooth extraction, and promote regeneration of alveolar bone to provide theoretical and experimental basis. PartⅠ: The effects of endogenous parathyroid hormone on the bone healing of extraction sockets in miceObjective: To study the effects of endogenous PTH on the healing of tooth extraction in mice.Methods: 18 PTH gene knockout mice(PTH-/-) and 18 wild mice(PTH+/+) were selected, and the bilateral maxillary first molars were extracted. To prepare section and observe the histology of the extracted tooth wound, the mice were killed in 7, 14, and 21d respectively.Results: Histological results demonstrate the less and thiner traberculae arranged in disorder, the bone mass was reduced, the healing of teeth extraction sockets were delayed and Oc.S/B.S were reduced significantly in PTH gene knockout mice, compared with those in the wild-type littermates.Conclusion: The deficiency of endogenous PTH would delay the bone healing of tooth extraction sockets in mice, and has important effects on the healing of tooth extraction socket in mice. PartⅡ:The effect of exogenous parathyroid hormone on the bone healing of extraction sockets in miceObjective: To study the effects of exogenous PTH on the healing of tooth extraction in mice.Methods: Tooth extraction models were built in 36 PTH+/+,and divided into A, B groups randomly. A group was injected with rhPTH 30μg / (kg ? d) in abdominal subcutaneou, once two days and for 20 days; B group was injected with saline in the same way. the mice were killed in 6, 13, and 20d respectively to observe the histology of the wound of the extracted tooth, and to comparise the differences between the experimental group and control group.Results : Histological results demonstrate that the healing of teeth extraction sockets was faster in the experimental group; Compared to the experimental group, the less and thiner trabecular bone, and is discontinuous in the Control group.Conclusion: Exogenous PTH has important effects on the healing of tooth extraction socket in mice.