Tendon injuries (
tendinopathies) are common in human and equine athletes and characterized by dysregulated
collagen matrix, resulting in tendon damage. We have previously demonstrated a functional role for microRNA29a (miR29a) as a post-transcriptional regulator of
collagen 3 expression in murine and human
tendon injury. Given the translational potential, we designed a randomized, blinded trial to evaluate the potential of a miR29a replacement
therapy as a therapeutic option to treat
tendinopathy in an equine model that closely mimics human disease.
Tendon injury was induced in the superficial digital flexor tendon (SDFT) of 17 horses. Tendon lesions were treated 1 week later with an
intralesional injection of miR29a or placebo. miR29a treatment reduced
collagen 3 transcript levels at week 2, with no significant changes in
collagen 1. The relative lesion cross-sectional area was significantly lower in miR29a tendons compared to control tendons. Histology scores were significantly better for miR29a-treated tendons compared to control tendons. These data support the mechanism of
microRNA-mediated modulation of early pathophysiologic events that facilitate tissue remodeling in the tendon after injury and provides a strong proof of principle that a locally delivered miR29a
therapy improves early tendon healing.