Effects of low intensity ultrasound on chondrogenic differentiation of mesenchymal stem cells embedded in polyglycolic acid- an in vivo study

초록

Biological growth factors were well studied in former chondrogenic differentiation of mesenchymal stem cells (MSCs) when mechanical stimulation also is an important factor in cartilage tissue engineering. As one of noninvasive mechanical stimulation methods, low-intensity ultrasound (LIUS)was used in this study to investigate the effects of LIUS on chondrogenic differentiation of MSCs by in vivo study. Materials and Mehotods: Rabbits MSCs were seeded into Polyglycolic acid (PGA) mesh, then it was implanted into subcutaneous of nude mouse. One group was uderwent ultrasound stimulation with an intensity of 200 mW/cm2 for 10 minutes every day, when the ultrasound stimulation was not used in control group. The gross and histological finding, biochemical analysis were performed at 1st, 2nd, 4th week respectively. Results: The gross finding shows that the size of implant trends to be slightly smalll following observation time, and the gloss of implant is similar to normal articular cartilage in two groups. Although type II collagen and GAG were produced in two groups were observed by histological finding, but the ultrasound group had bigger area and observed earlier than the control gourp; moreover, carilage formation in ultrasound group was mainly concentrated on central region when the control group was distributed in peripheral region. Synthesis of collagen and proteoglycna were alson increased significantly in ulasound group than the control gourp from biochemical analysis. Conclusion: LIUS in vivo not only promoting chondrogenic differentiation of MSCs, but also improving differentiated chondrocytes to produce extracellular matrix.