The effects of radial shock waves on the metabolism of equine cartilage explants in vitro

AIM: To investigate, in vitro, the effects of radial shock waves on the release of nitric oxide (NO) and synthesis of prostaglandin E2 (PGE2) and glycosaminoglycan (GAG), and liberation of GAG, from equine articular cartilage explants. METHODS: Equine cartilage from normal metacarpophalangeal and metatarsophalangeal joints was exposed to radial shock waves at various impulse doses and then maintained as explants in culture for 48 h. Shock waves were delivered at 1,876 Torr pressure and a frequency of 10 Hz. Treatment groups consisted of a negative control group, or application of 500, 2,000, or 4,000 impulses by use of either a convex handpiece (Group A) or concave handpiece (Group B). Synthesis of GAG was measured using incorporation of 35S-labelled sodium sulphate. Additionally, the synthesis of NO and PGE2, and content of GAG of the explants and media were determined. RESULTS: No significant effects (p>0.05) of radial shock-wave treatment were evident on the synthesis of NO or PGE2, or release of GAG by cartilage explants. However, radial shock waves decreased synthesis of GAG measured 48 h after exposure for all treatment groups other than the 500-impulse Group-A explants (p<0.05). CONCLUSIONS: Radial shock waves impact the metabolism of GAG in chondrocytes in equine articular cartilage. Further studies will be required to fully investigate the impact of this effect on the health of joints, and to elucidate the clinical impact.