Protective effects of extracorporeal shockwave on rat chondrocytes and temporomandibular joint osteoarthritis; preclinical evaluation with in vivo 99mTc-HDP SPECT and ex vivo micro-CT.

Abstract

OBJECTIVE\nExtracorporeal shockwave therapy (ESWT) has been shown to have chondroprotective effects on arthritic diseases. We investigated the effects of ESWT on temporomandibular joint osteoarthritis (TMJOA) using rat chondrocytes and TMJOA rat models.\n\n\nDESIGN\nCell viability and expression of pro-inflammatory cytokines, cartilage degradation, and apoptosis markers were measured in control, monosodium iodoacetate (MIA)-treated and ESWT plus MIA-treated chondrocytes in vitro, and intra-articular MIA injection (TMJOA) and ESWT on TMJOA rats in vivo. In vivo 99mTc-HDP SPECT/CT and ex-vivo micro-CT and histologic examinations were performed in rat models.\n\n\nRESULTS\nESWT plus MIA-treated chondrocytes showed increased cell viability significantly (p = 0.007), while decreased genetic expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6; p < 0.001 for each) and cartilage degradation markers (MMP3, MMP13, and BMP7; p < 0.001 for each), and number of apoptotic cells (p < 0.001) compared to MIA-treated chondrocytes. Changes in cytochrome c and cleaved caspase-3 levels relative to procaspase-3 were decreased over MIA-treated chondrocytes. ESWT on TMJOA rat models was associated with a significant decrease in pro-inflammatory and cartilage degradation markers, as demonstrated by real-time PCR and immunohistochemistry stains (p < 0.001 for each). On 99mTc-HDP SPECT/CT, the ESWT group showed a significantly lower uptake ratio compared to the TMJOA group (p = 0.008). Micro-CT analysis revealed that the ESWT group showed improved structure and bone quality compared to the TMJOA control group.\n\n\nCONCLUSIONS\nESWT was associated with a protective effect on cartilage and subchondral bone structures of TMJOA by reducing inflammation, cartilage degradation, and chondrocyte apoptosis.