| Objective:Periodontitis is a bacterial and infectious disease that occurs in the periodontal support tissue.Bacterial plaque and its products are essential factors in initiating periodontitis,periodontal pathogens are not only closely related to oral health,but also closely related to human health and living quality.At present,drugs used in the treatment of periodontitis are mainly antibiotics,but misuse and overuse of antimicrobials may cause antibiotic resistance and gastrointestinal reaction.Therefore,the development of drugs with periodontal inflammatory response inhibition and periodontal regeneration properties as well as the selection suitable carriers for local application to reduce systemic reactions have broad research prospects and clinical application potential.Studies have shown that erythropoietin(EPO)can promote cell proliferation and bone formation,and has a good function in regulating immune and inflammatory response.Chitosan(CS)is a natural macromolecule polysaccharide.It has many advantages,such as good biocompatibility,biodegradation,non-toxic and antibacterial.It has wide application prospects in drug delivery.But the gelation time of CS-β-sodium glycerophosphate is too long,which hinders the clinical application of this system.Gelatin(GEL)is a polyamphoteric electrolyte.When added to the CS-β-sodium glycerophosphate system,thecomponents of the system can be cross-linked rapidly at suitable temperature,which greatly shorten the gel time.Compared with the traditional nano scaffold or nano microspheres,the thermosensitive hydrogel can be made injectable,to achieve long-term,sustainable,a small amount of drug application,the loaded drug can be released continuously,stably and efficiently in the local and play a role.Therefore,chitosan/ β--sodium glycerophosphate/gelatin hydrogel loaded with EPO was selected to investigate the effect of the hydrogel on the experimental periodontal disease(EPD)in rats.Methods:chitosan/ β--sodium glycerophosphate/gelatin hydrogel loaded with EPO was prepared,and measured for the gelation time.The effect on the growth and adhesion of BMSCs was measured.Morphology of the hydrogel was examined by SEM.Wistar rats except control group and periodontitis group were injected with 25 μL of the solution on the proximal and distal alveolar crest of the maxillary first molar immediately after EPD induction once every 3 days for 14 days.Weighing and observating the gingival bleeding,gingival color,gingival shape and gingival texture in each group of rats.CBCT was used to detect the distance between alveolar bone crest(ABC)and cemento-enamel junction(CEJ)between the first molar and the second molar,Take the average as the result of each sample.HE staining was used to observe themorphological changes of the tissue sections.The degree of inflammatory cell infiltration,alveolar bone and cementum integrity between the first molar and the second molar was evaluated.Results:The gelation time of CS hydrogel loaded with EPO was(220±15)s.And BMSCs grew well with good adhesion.SEM showed that the hydrogels had loose and porous structure,the hole apertures were even and similar,between 40-80μm.The weight of the rats in each group had a similar growth rate during the experiment.The results from the general observation and CBCT analysis demonstrated that animals treated with EPO showed no significant bone resorption and alveolar bone height was significantly greater than that of the control group,which was close to that of the blank group.Histopathological analysis confirmed the healthy bone structure for naive group animals,while the EPD group exhibited bone loss.In particular,the EPD +hydrogel loaded with EPO group showed significantly alveolar bone regeneration.The results of these groups were significantly different from the EPD+hydrogel loaded with EPO group(P<0.05).Conclusion:1.The CS hydrogel loaded with EPO is an injectable and thermosensitive periodontal drug delivery system with good pore structure.2.It is able to control periodontitis and promote alveolar bone regeneration. |
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