| Mechano growth factor (MGF) is a novel growth factor from the alternative splicing of Insulin-like growth factor I (IGF-I) gene, which is expressed in response to the mechanic stimulation. Further studies have confirmed that MGF and its E peptide (MGF-Ct24E) could promote muscle hypertrophy, preserve cardiac muscle and repair the damage of nerves. Our previous studies concluded that MGF mRNA expressed highly in the cyclic stretched osteoblasts, suggested that MGF is a mechano-response molecule in bone and influences on the function of osteoblasts. these results indicated that MGF or MGF-Ct24E may play a major role in the process of bone healing. This research focus on the influence of MGF-Ct24E for fracture healing. Firstly, effects of the injected-MGF-Ct24E on radial fracture healing; Secondly, the preparation and property of the bioactive materials containing MGF-Ct24E. The main works and conclusions are included as follows:(1) The effects of the injected-MGF-Ct24E on radial fracture healingThe animal models used in this study, with 5mm bone defect, were produced in the middle of the left radius in rabbits. After 3 days of the surgical operation, 0.2 mL MGF (0.36 and 0.72 g/L, control: PBS) was injected into the ends of fracture areas once per day for continuous 5 days. And then following detections were taken:①After 4, 6, 8 weeks, X-ray photography was used to evaluate the healing of fracture;②At 8th week, histological examinations were performed to observe the cell morphology. All results showed that MGF-Ct24E can accelerate fracture healing significantly in a rabbit model and shows a dose-dependent manner in a certain range.(2) The preparation and property of the bioactive materials containing MGF-Ct24E.①The bioactive materials containing MGF-Ct24E was prepared in the Research Center of Bioinspired Material Science & Engineering;②GPC-MALLS was used to confirmed the influence of MGF-Ct24E introduction on molecular weight of PDLLA, which showed that the modified process reduced the molecular weight of PDLLA, however, did not weaken the function of PDLLA in fracture healing;③Amino Acid Analysis (AAA) and 1H-NMR were used to determine the introduction and bioactivity of MGF-Ct24E, which is key to the study of influences of bioactive materials on fracture healing. The results of AAA exhibited that MGF-Ct24E were coupled to the MHPLA at a concentration of 0.88μmol/g and the coupling efficiency was found to be 25%.④Examinations of cytocompatibity was used to probe the influences of MGF-Ct24E_bioactive materials on fracture healing. Firstly, osteoblasts were cultured on different materials films, with glass as control. The cytocompatibility of MHPLA with rats osteoblasts was estimated by means of cell morphology (by discrepancy microscope) and cell proliferation (by MTT assay) and ALP activity. The morphology observations revealed that the osteoblasts cultured on MHPLA spread wider than those on PDLLA and glass, and much more cells were confluent on MHPLA, comparing to the other two groups; The result of MTT showed osteoblasts grown faster on MHPLA than on HPLA and glass at 3rd, 5th, 7th; ALP showed that MHPLA delayed osteoblast differentiation. All results showed that the bioactivity of MGF-Ct24E on MHPLA is high. Moreover, effective time of MGF-Ct24E-bioactive materials on fracture healing is higher than MGF-Ct24E, which suggested potentially wide applications of MHPLA in biomedical areas, especially in tissue engineering.
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