An Experimental Study On The Overexpression Of P75NTR To Negatively Regulate BMSCs Involved In The Formation Of Bone Defects And Nonunion

Objective: By studying the effect of p75 NTR overexpression on rabbit bone marrow mesenchymal stem cells cultured in vitro,it is clarified that p75 NTR overexpression can negatively regulate the proliferation and osteogenic differentiation of BMSCs,and provide relevant intervention targets for improving the therapeutic effect of bone tissue engineering in repairing bone defects and nonunion.Methods : Select bilateral femurs from young New Zealand white rabbits,extract and culture rabbit bone marrow mesenchymal stem cells in vitro by whole bone marrow isolation and attachment method;construct a P75 NTR overexpression lentiviral vector expressing EGFP and infect primary rabbit bone marrow mesenchymal stem cells cultured in vitro;Cultivate to 7 days after infection.Observe the expression abundance of green fluorescent protein with a fluorescence microscope,and detect the overexpression of P75 NTR protein by Western blot;use CCK8 to detect the cell growth activity after infection;meanwhile,use osteogenic differentiation and culture to detect alkali Activity and the formation of mineralized nodules to evaluate the osteogenic differentiation capacity of infected cells.Results: Rabbit bone marrow mesenchymal stem cells isolated and cultured in vitro meet the needs of experimental design;P75NTR overexpression lentivirus infected with bone marrow mesenchymal stem cells can express green fluorescent protein(infection efficiency of about 90%),and the expression of P75 NTR protein increases significantly Compared with the negative virus control group and the normal cell group,the difference was significant(P <0.05).The over-expressing P75 NTR cell model was successfully constructed;the growth of rabbit bone marrow mesenchymal stem cells over-expressing P75 NTR was significantly inhibited(P<0.05);Rabbit bone marrow mesenchymal stem cells overexpressing P75 NTR were cultured in vitro to induce osteogenic differentiation,and their alkaline phosphatase activity was significantly reduced,and mineralized nodule formation was significantly reduced(the difference was statistically significant,P<0.05).Conclusions: P75 NTR,which is overexpressed in local tissues,participates in the formation of bone defect nonunion by inhibiting the growth and osteogenic differentiation of bone marrow mesenchymal stem cells around the bone defect.