Low‐intensity pulsed ultrasound irradiation attenuates collagen degradation of articular cartilage in early osteoarthritis‐like model mice

Abstract

Purpose Osteoarthritis (OA) is a combination of degeneration and destruction of articular cartilage due to mechanical stress, secondary synovitis, and bone remodelling. In recent years, early knee OA, a preliminary stage of structural failure in OA, has attracted attention as a potential target for therapy to prevent the onset of OA. Intra-articular administration of monoiodoacetic acid (MIA) induces OA-like symptoms, and low doses of MIA induce early OA like symptoms. In this experiment, a low-dose of MIA was induced to early OA model mice, which were then irradiated with low-intensity pulsed ultrasound (LIPUS) to examine whether LIPUS improves symptoms of early OA. Methods After 4 weeks of LIPUS irradiation, articular cartilage was observed at 1 and 4 weeks. The Osteoarthritis Research Society International (OARSI) scores were calculated using Safranin-O staining results. Cartilage degeneration was detected using Denatured Collagen Detection Reagent (DCDR). Results We observed a significant decrease in OARSI scores in the LIPUS irradiated group at week 4. The non-LIPUS group showed widespread areas of double positivity for Type II collagen and DCDR, whereas the LIPUS group showed only a small number of DCDR-positive areas. In addition, macrophage numbers counted in the articular capsule at week 1 showed a significant decrease in the LIPUS irradiated group. Lubricin detection showed that lubricin positive cell number was significantly increased by LIPUS irradiation at week 4. Conclusions These results suggest that LIPUS attenuates cartilage degeneration in early OA by relieving inflammation and enhancing the inhibitory effect of lubricin on cartilage degeneration.

Effectiveness of low-intensity pulsed ultrasound on osteoarthritis: molecular mechanism and tissue engineering

“…LIPUS can also inhibit disruptions in cartilage ECM metabolism and chondrocyte hypertrophy mediated by VEGF during OA progression by regulating VEGFA expression in OA chondrocytes and suppressing p38 MAPK activity (34). Kojima et al (35) abserved a notable reduction in Osteoarthritis Research Society International (OARSI) scores was noted in the group treated with LIPUS irradiation. Conversely, the non-LIPUS group exhibited extensive areas of dual positivity for collagen II and denatured collagen detection reagent (DCDR), while the LIPUS group displayed a limited number of DCDR-positive areas.…”