| Objective:To evaluate the new citric acid-based biodegradable bone biomaterial BPLP-PSer-HA for repairing bone defects in rats.Materials and methods:From the view of bionics,we synthesized new citric acid-based biodegradable bone biomaterial(Biodegradable Photoluminescent Polymer-Phosphoserine-Hydroxylapatite,BPLP-PSer-HA)which was used to repair bone defects in rats.Compared with Poly(1,8-Octanediol-co-Citric acid)-Hydroxylapatite(POC-HA)、Poly(lactide-co-glycolide)-Hydroxylapatite(PLGA-HA)、autogenous bone(AB)and control(CON)group,the effect of BPLP-PSer-HA for repairing bone defects(femoral condyle defect,calvarial defect)in terms of biocompatibility,degradability,osteoconduction,osteointroduction,was evaluated by the imaging and histological staining of samples taken at 4 weeks,8 weeks and 12 weeks after operation.Results:At 4 weeks,8 weeks,12 weeks after operation,Micro-CT reconstruction images and bone mineral density(BMD)of volume of interest(VOI)analysis showed that the quantity of new bone increased gradually with time in all groups,and autogenous bone(AB)group had the fastest rate of repairing bone defects,defect none-repaired(CON)group had the slowest rate of repairing bone defects,the rate of materials group was between the AB group and CON group at each observation time point of two bone defect models.In material groups,the repairing speed in BPLP-PSer-HA material group was faster than that in POC-HA and PLGA-HA groups,and the repairing speed in POC-HA group was faster than PLGA-HA group.Histological staining showed that the materials were wrapped by a large amount of fibrous tissue and were degraded gradually with time.There was no obvious inflammatory cell around the materials.The quantity of new bone formation was consistent with the imaging results and new bone tissue contained a large number of cartilage.In terms of material degradation rate,the PLGA-HA material degradation rate is the fastest in all material groups,and due to the degradation speed of PLGA-HA faster than the speed of bone formation,a large number of cavities were formed in the newly grown tissue.The degradation speed of BPLP-PSer-HA and POC-HA materials was consistent with the bone formation speed.Alkaline phosphatase(ALP)staining and osteocalcin(OCN)immunohistochemistry results showed that the number of osteoblast of AB group is the highest and CON group is the lowest among all groups.In material groups,the number of osteoblasts in BPLP-PSer-HA group is higher than POC-HA which is higher than PLGA-HA group.Conclusion:In this study,BPLP-PSer-HA is able to promote the repairing of femoral condyle defect derived from endochondral ossification and calvarial defect derived from intramembranous ossification via endochondral ossification in rats,and have good biocompatibility,suitable degradation rate.Compared with POC-HA and PLGA-HA biomaterials,BPLP-PSer-HA biomaterial has better osteoinductivity.Therefore,BPLP-PSer-HA is a kind of good filling biomaterial for bone defect. |
