| Objectives Establishment of Femoral condyle bone defect model in rabbits,Obser ving the ossification of tantalum-bone interface and related osteogenic protein expres sion by histological examination,to study the osteogenic mechanism of tantalum-bo ne interface,to evaluate the bone repair ability of PL modified porous tantalum sc affold,which provides a theoretical basis and scientific basis for its clinical applicat ion.Methods 1 Experimental materials and grouping: Select several domestically-adopted porous tantalum scaffolds that are suitable for ultrasonic cleaning,and partially use PL for modification.Thirty-six experimental rabbits were randomly divided into three groups: PL porous tantalum group,porous tantalum group and blank control group.2 Operation steps: anesthetized rabbits,the left femoral condyle to hair,skin preparation,disinfection,shop,in the left femoral condyle at about 2.5cm long incision,cut the skin and subcutaneous tissue,gradually exposed femoral condyle,using 3mm Kirschner wire skeleton drill into the lateral femoral condyle.Manufacture of lacunar bone defects with appropriate size.The porous tantalum scaffolds were implanted into the bone defects of each experimental group.The scaffolds were close to the host bone tunnel walls.The blank control group only made bone defects without porous tantalum scaffolds.The incision was sutured with the absorbable line,and the anti infection treatment was performed after the operation.3 Postoperative animal basic condition observation.4 Materials and specimens Anatomical observations: Each group of experimental rabbits were sacrificed 2,4,8 and 16 weeks after surgery.Materials were obtained and the anatomy of the bone defect was observed in each group.5 Histological examination: HE staining was used to observe the osteogenesis at the iliac-bone interface;Immunohistochemistry was used to detect the expression of the related osteogenic proteins Integrin-β1,Vinculin,F-actin,p38 and pp38.After image acquisition,Image-Pro-Plus 6.0 images were used to analysis yielded IOD values for statistical analysis;Hard tissue section Goldner trichrome staining method to observe the different stages of new bone ingrowth of domestic porous tantalum scaffolds,and VG staining for new bone quantification analysis.6 Scanning electron microscopy of tantalumbone interface: the attachment of homemade porous tantalum scaffold and the growth of new bone were observed.Results 1 During the 2 days after surgery,the experimental rabbits had poor mental status,low activity,eating a little feed and drinking water,and the amount of feces was significantly reduced compared with before surgery.After one week,the activity of experimental rabbits increased significantly,and the diet and mental status returned to normal.After 2 weeks,the limbs activities basically returned to normal.There was no redness,exudate,and prolapse of stents after the operation.2 Specimen general observation: There was no obvious inflammatory reaction in the anatomic observation of the surgical site at each postoperative period,and there was no loosening and prolapse of the porous fistula stent.The scaffolds of each group were gradually covered by new tissue,while the new control group had less bone callus and the bone repair effect was not as good as that of the other two groups.3 HE staining results showed that a small amount of connective tissue,capillaries,and osteoblasts were seen in each group at 2 weeks postoperatively.No new bone callus was seen;at the 4th week after surgery,there were more new cartilage matrixes in the PL porous tantalum group and a small amount of neonatal cartilage in the porous tantalum group.No obvious cartilage was found in the cartilage and blank groups.After 8 weeks,the scaffolds in the PL porous tantalum group and the porous tantalum group were basically covered by the new osteophytes.The blank group had a small amount of osteophytes.The stents were completely covered by the new tissue at 16 weeks after operation.PL porous tantalum group and porous tantalum group were significantly more than the blank group.4 Immunohistochemistry results showed that: Integrin-β1,Vinculin and F-actin: the expression of PL porous tantalum group and porous tantalum group was higher than the blank control group at various time points postoperatively;In the Poria cocos group(P<0.05),the expression of the PL porous tantalum crest group was higher than that of other time points at the 4th week.The expression of the porous quinone group and the blank control group was higher than that of other time points at the 8th week postoperatively(P<0.05).p38: Compared with the blank control group,the expression levels of PL porous tantalum group and porous tantalum group were higher than those in the control group at each time point after the operation.The expression of PL porous tantalum group was higher than that in the porous tantalum group at the time of 2,4 and 8 weeks after the operation(P<0.05);Expression at 4 weeks was higher than that at other time points.The expressions in the porous tantalum group and the blank control group at the 8th week after operation were higher than those at other time points(P<0.05).pp38: The expression of PL porous tantalum group was significantly higher than that in the blank control group at 2,4,and 16 weeks after the injection(P<0.05).The expression of the porous tantalum group was higher than that of the blank group at each time point.Sputum group expression was higher than that of porous tantalum group(P<0.05).The expression of PL porous tantalum group was higher than that of other time points at 4 weeks.The expression of porous tantalum group and blank control group at the 8th week after operation was higher than other time points(P<0.05).5 Hard tissue section observation: the early porous tantalum pores can be seen in the sporadic orange red new bone like bone.With the time of implantation,the orange red new bone and the green mineralized bone gradually increased in the pore,and the bone gradually matured.The new bone ingrowth analysis showed that the percentage of new bone area in the PL porous tantalum group was higher than that in the porous tantalum group at the same time point(P<0.05).The new bone area scores of both groups gradually increased with the time of stent implantation and postoperatively.The new bone area scores at 16 weeks were higher than those at other time points(P<0.05).6 Scanning electron microscopy results: At the same time point,the number of osteoblasts and collagen fibers in the porous tantalum group were more than those in the porous tantalum group.The new bone gradually grew into the pores of the scaffold,and the scaffold was gradually surrounded by new bone.Conclusions 1 PL modified porous tantalum scaffolds have stronger bone repair ability.2 PL promotes the entry of new bone into porous tantalum and accelerates the maturation of new bone.3 PL can promote the early expression of osteogenic protein Integrin-β1,Vinculin,and F-actin,activate p38 MAPK pathway,and promote the early migration,adhesion,proliferation and differentiation of osteoblasts. |
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