| Periodontitis is a high incident disease which causes periodontal tissue destruction, including connective attachment loss and alveolar bone resorption, thereby resulting in tooth loss. To date, periodontal reconstruction based on infection control is still the key solution for periodontal treatment. However, the bottle neck for periodontal reconstruction is that it is difficult to regenerate cementum. Cementum represents a unique avascular mineralized connective tissue that covers the root surface of the teeth. It provides the interface through which Sharpey’s collagen fibers of the periodontal ligament are anchored to the root surface.A number of studies show that Cementum protein 1 (CEMP1, one kind of growth factor) promotes cell attachment, differentiation, extracellular matrix deposition, and affects the composition, and morphology of hydroxyapatite crystals formed by human cementoblast cells in vitro. These observations confirm that CEMP1 plays an important role during the cementum formation and the bio-mineralization process.We acquired abundant rhCEMP1 expressing in a prokaryotic expression system. To examine whether rhCEMP1 expressed in a prokaryotic expression system had the same cell interaction with that of a eukaryotic one, we measured the expression of cemp1 mRNA after rhCEMP1 induction. The result showed in Fig.3 indicated that cemp1 mRNA was expressed in both control and experimental PDLCs at 48 h of culture. The expression of cemp1 was observed in the experimental culture (0.25μg/ml rhCEMP1) was about 3 folds as much as the control culture (0 μg/ml rhCEMP1)This study was carried out to test the hypothesis that, CEMP1 had the capacity to guide ordered HA formation as it accumulated at targeting site. Crystals induced by protein were prepared by biomimetic method. The effects of CEMP1 concentrations (0-100μg/ml) on the rate of calcium phosphate precipitation was monitored during 48 hours. The results showed that recombinant cementum protein 1 (rhCEMPl) affected the crystal nucleation and growth. At lower rhCEMP1 concentrations (0-50μg/ml), limited mineral formation occurred and only small bundles of HA crystals were found. However, with 100μg/ml of rhCEMP1, a predominance of organized linear needle-like HA crystals were observed. FTIR revealed the characteristic bands of HA appearing at 1106 cm-1,557cm-1, and 598 cm-1. Therefore, increasing the concentration of rhCEMP1 can lead to the formation of ordered bundles of HA crystals in vitro.In the present study, poly (ethylene glycol) stabilized amorphous calcium phosphate (ACP) nanoparticles were prepared by wet-chemical method and then loaded with recombinant human CEMP1 (rhCEMP1) for controlled release. The results showed that poly (ethylene glycol) stabilized ACP nanoparticles formed a core-shell structure with sustained release of rhCEMP1 for up to 4 weeks.An electrospun multiphasic scaffold constituted of poly (s-caprolactone) (PCL), type-I collagen (COL) and rhCEMP1/ACP were fabricated. rhCEMP1/ACP/PCL/COL scaffold could suppress PDLC proliferation behavior and up-regulate the expression of cementoblastic makers including CEMP1 and cementum attachment protein while down-regulate osteoblastic makers including osteocalcin and osteopontin when it was co-cultured with PDLC in vitro for 7 days. Histology analysis of cementum after being implanted with the scaffold in rats for 8 weeks showed that there was cementum-like tissue formation but few bone formation.These results indicated the potential of using electrospun multiphasic scaffolds for controlled release of rhCEMP1 for promoting cementum regeneration in reconstruction of the periodontal complex. |
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