The purpose of this study was to investigate the effects of extra corporeal shock waves (ESW) therapy on the metabolism of healthy and osteoarthritic human chondrocytes, and particularly on the expression of IL-10, TNF-α and β1 integrin.

Human adult articular cartilage was obtained from 9 patients (6 male and 3 females), with primary knee osteoarthritis (OA), undergoing total joint replacement and from 3 young healthy donors (HD) (2 males, 1 female) with joint traumatic fracture. After isolation, chondrocytes underwent ESW treatment (Electromagnetic Generator System, Minilith SL1, Storz Medical) at different parameters of impulses, energy levels and energy fluxes. After that, chondrocytes were cultured in 24-well plate in DMEM supplemented with 10% FCS for 48 hours and then β1 integrin surface expression and intracellular IL-10 and TNF-α levels were evaluated by flow-cytometry.

At baseline, osteoarthritic chondrocytes expressed significantly lower levels of β1 integrin and higher levels and IL-10 and TNF-α levels. It has been recently reported that ESW may be useful to treat OA in dogs, and veterinarians have begun to use ESW also to treat OA in horses.

Following ESW application, while β1 integrin expression remain unchanged, a significant decrease of IL-10 and TNF-α intracellular levels was observed both in osteoarthritic and healthy chondrocytes. IL-10 levels decreased at any impulses and energy levels, while a significant reduction of TNF-α was mainly found at middle energies.

Our study confirmed that osteoarthritic chondrocytes express low β1 integrin and high TNF-α and IL-10 levels. Nonetheless, ESW treatment application down-regulate the intracellular levels of TNF-α and IL-10 by chondrocytes, suggesting that ESW might restore TNF-α and IL-10 production by osteoarthritic chondrocytes at normal levels thus potentially interfering with the pathologic mechanisms causing cartilage damage in OA and representing the theoretical rationale for using ESW as therapy of OA.