Abstract

Extracorporeal shock waves (ESWs) are efficacious for the treatment of several musculoskeletal disorders, but our understanding of the cellular mechanisms by which ESWs achieve their beneficial effects is incomplete. The objective of this study was to determine the effects of ESWs on the expression of lubricin in tendon and septa. The effect of ESW dose on lubricin expression in rat tendons and septa in the distal hindlimb was evaluated at 4 days post-treatment, with the contralateral limb as the control. Immunohistochemistry, using an anti-lubricin antibody, was performed to determine the distribution of lubricin in tissues. Lubricin staining in the matrix and intracellularly was evaluated semiquantitatively in 10 tendons and 4 septa in the ESW-exposed areas. The majority of the non-ESW-treated control tendon and septa samples did not stain for lubricin, with the exception of trace stainings. Positive immunostaining for lubricin was observed in all of the tendons and septa of the low-dose and high-dose ESW-treated hindlimbs. There was a clear increase in lubricin expression with increasing ESW dose. The results provide a basis for the hypothesis that increased lubricin deposition in tendons and septa following ESW treatment contributes to the beneficial effects of such therapy by enhancing tribology.