| Objective: New Zealand big ear rabbit model of articular cartilage injury was constructed.By observing the repair level of articular cartilage injury in rabbits under different intervention conditions,the role of Runx2 gene transfected bone marrow mesenchymal stem cells in the repair of articular cartilage injury was explored,in order to provide new clinical therapeutic targets for the majority of patients with articular cartilage injury.Methods: Twenty New Zealand big ear rabbits,male,weighing about 2.5-2.7 kg.After a week of adaptive feeding,the knee joint cartilage injury model was established.After successful modeling,the knee joint was randomly divided into five groups: A: blank control group,B: model + saline group,C: model + sodium hyaluronate group,D: model + bone marrow mesenchymal stem cells group,E: model + Runx2 transfection group.The knee joint was harvested at the 4th and 8th weeks,and then the cartilage group was harvested.Tissue repair was observed and scored.The expression of type II collagen(ColII),Agg,Colx,ColI and Runx2 was detected by RT-PCR.The expression of Runx2 protein in each group was detected by Western Blot test.The cartilage sections of each group were stained by HE and Masson staining respectively.Toluidine blue staining was used to analyze the morphological differences of the restorations.Results:1.After successful modeling of articular cartilage injury,the cartilage defect of each experimental group was repaired to varying degrees.Histological naked eye observation showed that after 4 weeks of intervention,the repair effect of sodium hyaluronate group was the best compared with the blank control group;after 8 weeks of intervention,the repair effect of Runx2 transfected bone marrow mesenchymal stem cells group was the best compared with the blank control group.2.The results of RT-PCR assay showed that after 4 weeks of intervention,the expression of histone mRNA in all experimental groups was significantly higher than that in blank control group(P<0.01).The expression of histone mRNA in sodium hyaluronate group wassignificantly higher than that in other experimental groups(P<001).After 8 weeks of intervention,the expression of histone mRNA in all experimental groups was significantly higher than that in blank control group(P<0.01).Except for type I collagen,the Runx2 transfection group had significant difference.Compared with sodium hyaluronate group(P <0.05),the expression of other protein mRNA in sodium hyaluronate group was significantly higher than that in sodium hyaluronate group(P < 0.01).3.Western Blot experiment showed that after 4 weeks of intervention,the expression of type II collagen protein in each experimental group was significantly higher than that in the blank control group(P < 0.01).The expression of type II collagen protein in sodium hyaluronate group was significantly higher than that in other experimental groups(P < 0.05).At the 8th week,the expression of type II collagen protein in each experimental group was significantly higher than that in the blank control group(P < 0.01).The expression of type II collagen protein in Runx2 group was significantly higher than that in other experimental groups(P < 0.01).4.The results of HE staining and Masson staining showed that the cartilage defects in each experimental group were restored to varying degrees.The sodium hyaluronate group had the best cartilage repair in the 4th week,and the defect was basically filled with the restoration.At the 8th week,the Runx2 group had the best partial repair of cartilage defects,which were not only filled with white repair tissue,but also with the surrounding normal cartilage.Fusion,blurred boundaries.Conclusion:1.It is difficult to repair articular cartilage injury by self-healing.Intra-articular injection of Runx2 gene into bone marrow mesenchymal stem cells can promote the repair of articular cartilage injury.2.Injection of bone marrow mesenchymal stem cells can promote the repair of cartilage injury to a certain extent,while the repair effect of bone marrow mesenchymal stem cells transfected with Runx2 gene is better.It shows that Runx2 gene can regulate the proliferation and differentiation of bone marrow mesenchymal stem cells to some extent and promote the repair of injury,but its main mechanism still needs further study.3.Compared with other experimental groups,Runx2 transfection group had the best effect on cartilage repair at the 8th week,which indicated that Runx2 gene had a better promoting effect on cartilage repair in a long time. |
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