Micro RNAs play an important role in the process of growth and senescence of living organisms, and participate in the important biological processes of MSCs, including proliferation, differentiation, signal transduction and death. The effect of miR-let-7 family members on the differentiation of bone marrow mesenchymal stem cells into neurons can promote stem cell transplantation. To investigate the role of miR-let-7 b in promoting the differentiation of rat bone marrow mesenchymal stem cells into nerve cell...