The potential application of LIPUS and PEMF on cartilage and chondrogenic differentiation
This thesis starts with a review of the scientific literature on the use and mechanism of low-intensity pulsed ultrasound (LIPUS) and pulsed electromagnetic fields (PEMF) applied on articular cartilage, chondrocytes and chondrogenesis in order to compare these two non-invasive procedures regarding their efficacy and mechanism of action.
A simple and rapid cell seeding procedure for both calcium phosphate ceramic scaffolds and polymer scaffolds is described. Poly-(D,L-lactic acid) and β-tri-calcium phosphate scaffolds were tested with approximately 60% efficiency independent of the initial cell density. This did not affect the proliferation capacity of the cells.
Furthermore, a study is presented on the effects of LIPUS and PEMF on articular cartilage explants from porcine knee joints and human osteoarthritic cartilage after 4 weeks. LIPUS or PEMF prevented degenerative changes in pig knee cartilage explants. LIPUS reduced degeneration in human cartilage samples. LIPUS treatment seems to have more potency in the treatment of osteoarthritis than PEMF treatment.
LIPUS also appears to affect the chondrogenesis of progenitor cells, whereas PEMF hardly has an effect. Treatment with PEMF had no effect on expression of genes involved in chondrogenesis in C3H10T1/2 cells, whereas treatment of LIPUS resulted in an enhancement of the expression of COL2A1 at 4 weeks. In ATDC5 cells, LIPUS enhanced SOX9 and ACAN expression, but had no effect on COL2A1. LIPUS treatment also resulted in a short increase of COL10A1 expression at week 2.