Study On The Repair Of Rat Fenoral Defect With Marrow Mesenchymal Stem Cells Combined With PRP-hydroxyapatite Scaffold

ObjectiveTo observe the effect of MSC(mesenchymal stem cells)combined with PRP(platelet-rich plasma)-hydroxyapatite scaffold on the repair of femoral defects.MethodsThirty rats were selected,with an unlimited body weight of about 220-280 g.Eighteen rats were randomly selected and randomly divided into three groups,with six groups each.They were labeled as MSC composite PRP-hydroxyapatite scaffold group(group A experimental group),MSC composite hydroxyapatite scaffold group(group B simple scaffold group),and blank group(group C).A model of a sphenoid bone defect in the left middle femur of the rat was prepared and the remaining femur was separated.The defect in group A was filled with BMSC / PRP-hydroxyapatite,and group B was filled with MSC /hydroxyapatite scaffold.Group C is not filled with anything.Two rats were selected for BMSC culture and passed to three generations for experiments.The remaining nine rats were selected for heart blood preparation for PRP and reserved.Morphological and imaging examinations were performed at 4,8,and12 weeks after modeling.The experimental animals were sacrificed,and femoral specimens were taken for in vitro observation and histological observation.The area of new bone trabecula in the defect area was calculated,and the repair status of the bone defect in each group was compared,andstatistical calculation was performed.Results1.Morphological observation: At 4 weeks,the morphological observation of the affected sides of the three groups A,B,and C did not show significant limb abduction and external rotation,and the affected limbs could not bear weight.At 8 weeks,no obvious shortening and external or internal rotation of the affected limbs were seen in the A and B groups.The walking gait of group A tended to be normal,and the affected limb showed partial weight bearing.In group B,the improvement of walking was normal compared with that at 4 weeks,but the distance between the front and rear paws of the affected side was slightly shorter than that of the test,and the affected limb was partially loaded.Different shortening of the affected limbs occurred in group C.At 12 weeks: the affected limbs in group A and B can be fully weight-bearing,and at the same time,the front and back steps can be seen on the same healthy side.Group C:The affected limbs were found to have different degrees of shortening,accompanied by external rotation deformity,and the formation of pseudo joints in the bone defect.2.Specimen observation: at 4 weeks: there was a large amount of fibrous connective tissue in the bone defect of group A,which was closely connected with the stent,and there was fibrous tissue formation in group B,but there was no connection with the stent in group A,which was visible in group C.At 8weeks: it can be seen that the scaffolds from the bone defects in groups A and B are wrapped with fibrous connective tissue and are closely connected to the fracture end,but the stent in group A is significantly less than that in group B,suggesting that the degree of ossification of group A is higher than that of B Group high.In group C,there was no osseointegration at the fracture ends,and fibrous tissue wrapping was seen at the fracture ends.At 12 weeks: continuous bone cortex was seen in the bone defect in group A,and there were extra calluson both sides of the fracture end.No scaffold was found in the bone cortex of the defect.Bilateral stump is a plastic hyperplastic epiphysis,suggesting that healing has entered the bone plastic phase.In group B,most of the bone cortex was continuous in the bone defect.Only a small part of the stent remained on the newly formed bone cortex.In group C,no cortical bone formation was observed.Both sides of the stump were surrounded by organic fibrous tissue,the bone marrow cavity was closed,and bilateral fractures were not continuous.3.Imaging observations: At 4,8,and 12 weeks,the amount of callus and bone defect repair in group A were better than those in group B,and no obvious repair phenomenon appeared in group C.(4)Histological observation: The area of new bone formation in group A was larger than that in group B,and the difference was statistically significant(P <0.05).There was no obvious repair in group C.4.Histological observation: specimens were taken for HE staining at 4,8,and 12 weeks.At 4 weeks,the area of new bone formation in group A was larger than that in group B.The area of new bone trabeculae in groups A and B was more than that in group C.The difference was statistical Significance(P <0.05).At 8 weeks: The area of trabecular bone in group A was significantly different from that in group B(p <0.05),suggesting that the area of trabecular bone in group A was larger than that in group B,and the composite stent group healed significantly faster than the stent group alone..Group C also saw the formation of a large number of fibrous tissues,with only part of the new bone trabeculae.At 12 weeks: the bone marrow cavity was formed in group A,a large number of bone trabeculae were connected to each other in an orderly arrangement,and a large number of osteoblasts were seen,and lamellar bone was formed in the defect area.Group B saw a large number of trabeculae,but the arrangement was less orderly,and there were fewer osteoblasts than group A.In group C,some bone formation was observed,trabecular bone was sparse,and thedefect site was replaced by a large amount of fibrous connective tissue.ConclusionBMSC combined with PRP-hydroxyapatite scaffold has a good repairing effect on the repair of bone defects.It is non-immunogenic and promotes rapid bone formation.