J.Leonard Goldner Award 2008. Effect of extracorporeal shock wave therapy on cultured tenocytes

Little has been reported about the biologic effect of shock waves on human normal or pathologic tendon tissue. We hypothesized that inflammatory cytokine and MMP production would be down-regulated by shock wave stimulation.

Diseased Achilles tendon tissue and healthy flexor hallucis longus tissue were used. Shock wave treatment was applied to cultured cells at 0.17 mJ/mm(2)energy 250, 500, 1000, and 2000 times.

A dose-dependent decrease in cell viability was noted in cells receiving 1000 and 2000 shocks (86.0 +/- 5.6%, p = 0.01 and 72.4 +/- 8.9%, p = 0.001) as compared with the normal control. Cell count in the 500-shock group increased by 23.4% as compared with the control (p = 0.05). The concentration of MMP 1, 2, and 13 was higher in diseased tenocytes as compared with normal cells (p = 0.04, all comparisons). IL-6 levels were higher in the diseased tenocytes as compared with normal tenocytes (44.10 +/- 16.72 versus 0.21 +/- 0.55 ng/ml, (p < 0.05). IL-1 levels in normal cells increased (2.24 +/- 5.02 ng/ml to 9.31 +/- 6.85 ng/ml) after shock wave treatment (p = 0.04). In diseased tenocytes, levels of MMP-1 (1.12 +/- 0.23 to 0.75 +/- 0.24 ng/ml; p = 0.04) and MMP-13 (1.43 +/- 0.11 to 0.80 +/- 0.15 ng/ml; p = 0.04) were significantly decreased after shock wave treatment. The IL-6 level in diseased tenocytes was decreased (44.10 +/- 16.72 to 14.66 +/- 9.49 ng/ml) after shock wave treatment (p = 0.04).

Higher levels of MMPs and ILs were found in human tendinopathy-affected tenocytes as compared with normal cells. ESWT decreased the expression of several MMPs and ILs.

This mechanism may play an important role in shock wave treatment of tendinopathy clinically.