【ABSTRACT】 Objective To investigate the ability of bone marrow mesenchymal stem cells (BMSCs) in differentiation into neuroblasts induced by injectable platelet-rich fibrin (i-PRF) in vivo . Methods BMSCs were isolated from tibias of SD neonatal rats aged 10-15 days and cultured until the 4th generation, which were later randomly divided into control group(group A) and experimental groups(group B,group C). Prepare i-PRF using modified low-speed centrifugation and take 0, 150, 300ul i-PRF into each group of 12% FBS complete medium and co-culture with BMSCs.Reduced 50% i-PRF and serum concentration after 2 weeks. The morphological changes of cells were observed on the7th,14th and 21th days and the induction results were detected by immunohistochemistry and Western blot. Results The morphology of BMSCs began to change after 7 days of i-PRF induction, and synaptic growth and neuron-like cell morphology appeared 21 days later. Cell immunohistochemistry showed that Nestin protein expression was positive in the group B and group C. Immunofluorescence staining showed that S-100 β protein expression was positive in the group B and group C.Western blot analysis showed that the relative expression of nestin and N-cadherin protein in group B>group C >group A , and the difference was statistically significant (P<0.05). Conclusion i-PRF can effectively induce the differentiation of BMSc into neuroblasts,but is regulated by i-PRF concentration.