Parathyroid hormone (PTH) exerts multiple effects such as regulating bone remodeling, promoting angiogenesis, etc., and it is an active factor with great application potential for bone repair. In recent years, with the development of scaffold material loading strategies and parathyroid hormone-related peptides (PTHrPs), in situ loading of PTH or PTHrPs on scaffold materials to promote bone defect healing gradually becomes possible. Based on the current status and challenges of intermittent PTH (iPTH) for bone tissue engineering, the review summarizes the in-situ application strategies of PTH and the construction of PTHrPs as well as current problems and further directions in this field, with a view to propel the clinical application of scaffold materials loaded with PTH or PTHrPs in situ.
In the present research, the effects of sintered bone modified with surface mineralization/P24 peptide composite biomaterials on the adhesion, proliferation and osteodifferentiation of MC3T3-E1 cells were investigated. The experiments were divided into three groups due to biomaterials used: Group A (composite materials of sintered bone modified with surface mineralization and P24, a peptide of bone morphogenetic protein-2); Group B (sintered bone modified with surface mineralization) and Group C (sintered bone only). The three groups were observed by scanning electron microscopy (SEM) before the experiments, respectively. Then MC3T3-E1 cells were cultured on the surfaces of the three kinds of material, respectively. The cell adhesion rate was assessed by precipitation method. The proliferative ability of MC3T3-E1 cells were measured with MTT assay. And the ALP staining and measurement of alkaline phosphatase (ALP) activity were performed to assess the differentiation of cells into osteoblasts. The SEM results showed that the materials in the three groups retained the natural pore structure and the pore sizes were in the range between 200-850 μm. The adhesive ratio measurements and MTT assay suggested that adhesion and proliferation of MC3T3-E1 cells in Group A were much higher than those in Group B and Group C (P<0.05). The ALP staining and ALP activity of MC3T3-E1 cells in Group A were significantly higher than those in Group B and Group C (P<0.05). The sintered bone modified with surface mineralization/P24 composite material was confirmed to improve the adhesion rate and proliferation and osteodifferentiation of MC3T3-E1 cells, and maintained their morphology.