Study Of Allogeneic Bone Marrow Mesenchymal Stem Cell Transplantation For The Treatment Of Knee Cartilage Defect In Rabbits

Objective In this study,bone marrow mesenchymal stem cells(BMSCs)were extracted from rabbits to study the optimal density of intra-articular injection of BMSCs in the treatment of cartilage defects,and the therapeutic effect of this method and cartilage fragments combined with platelet rich plasma(PRP)gel on cartilage defects was compared.Methods 1.Femoral bone marrow was extracted from two New Zealand white rabbits,and BMSCs were cultured and passaged by adherent method.BMSCs were identified by flow cytometry.2.Thirty New Zealand white rabbits were randomly divided into 5 groups to establish cartilage defect models at bilateral trochlear of femur.After 1 week of successful modeling,1ml normal saline was injected into the knee cavity of the blank group,and 1ml BMSCs with a cell density of 10~5/ml,10~6/ml,10~7/ml and 10~8/ml were injected into the 10~5,10~6,10~7 and 10~8 groups,respectively.After 6 weeks and 12 weeks,3 animals of each group were sacrificed to take a trochlear specimen.Gross morphological,HE-staining,Safranin-O-fast green-staining,type?and type?collagen-staining were observed to evaluate of cartilage tissue repair effect.Data were analyzed statistically.3.Twenty-four New Zealand white rabbits were randomly divided into four groups to establish cartilage defect models.The blank group was treated with 1ml saline injection.Microfracture group was treated with microfracture.In the cartilage fragments gel group,10ml venous blood of rabbits was extracted and centrifuged to get 0.5ml PRP,then mixed with cartilage fragments.The gel was prepared and transplanted into the defect area.In the BMSCs group,1ml of BMSCs with a cell density of 10~7/ml was injected into the joint.After 6 weeks and 12 weeks,3 animals of each group were sacrificed to take a trochlear specimen.Gross morphological and histological staining were observed to evaluate of cartilage tissue repair effect.Data were analyzed statistically.Results 1.In the cell density study,there was no significant regeneration of the defect cartilage in the blank group after treatment.10~5 group,10~6 group and 10~7 group showed cartilage regeneration,type?and type?collagen staining were enhanced.The difference was statistically significant(P<0.05).The results of cartilage repair in 10~8 groups were similar to those in 10~7 group(P>0.05).2.In the study of BMSCs and cartilage fragment gel,there was no significant regeneration of the defect cartilage in the blank group after treatment.Microfractures group,cartilage fragments gel group,BMSCs group showed cartilage regeneration,type?and type?collagen staining were enhanced.The difference was statistically significant(P<0.05).Conclusion In the cell density study,the effect of cartilage repair increased with the increase of density within a certain range,and the tissue repair ability remained stable when the density exceeded 10~7/ml.Cartilage fragments combined with PRP gel transplantation were effective in the treatment of cartilage defects,and the results were better than those of microfracture techniques.However,articular injection of BMSCs was more in favor of the recovery of cartilage structure and function.Articular injection of BMSCs is an effective method for the treatment of cartilage defects,and the appropriate cell density is conducive to the improvement of cartilage regeneration.Further study on the mechanism of intraarticular BMSCs in cartilage repair will contribute to its clinical application value.