Micro-Vibration Environment Promotes Bone Marrow Mesenchymal Stem Cells (BMSCs) Healing of Fracture Ends and Matrix Metalloproteinase-9 (MMP-9) Expression

Abstract

When the muscle is stimulated by micro-vibration environment, it will produce a mechanical effect on skeletal muscle, thereby promoting growth of skeletal muscle cells. Bone marrow mesenchymal stem cells (BMSCs), as mechanically sensitive cells, have ability to multipolarize and multiple tropisms. This experiment explores the effect of BMSC cells on fracture end healing in fracture rats in a micro-vibration environment, and further explores whether it promotes the healing of fracture end to provide biological treatment ideas for the clinical repair of fracture patients. After modeling, SD rats were assigned into blank group, control group, and experimental group (treated with BMSCs) followed by analysis of bone volume fraction and bone trabecular thickness and number by Micro-CT, callus growth by H&E staining, and expression of p38 and MMP-9 by immunohistochemical staining. The BV/TV value of experimental group was (0.41±0.06), Tb.Th value (0.08±0.01), Tb.N value (3.96±0.48) and was higher than other two groups (P < 0.05). The growth of capillaries, trabecular bone, fibrous callus and cartilaginous callus in experimental group showed increased growth and the calcification was observed at the edge of cartilage callus. In addition, experimental group showed increased distribution area of MMP-9 and elevated expression of MMP-9 and p38MAPK. In conclusion, the micro-vibration environment can effectively promote the chemotaxis of BMSC cells to the fracture site to activate ossification, thereby promoting the proliferation and ossification and differentiation of BMSC, and further promoting the repair of fracture ends.