Intrasound Therapy Improves the Mechanical Properties and the Morphology of Tendons in Fluoroquinolone-Induced Achilles Tendinopathy

Abstract

Fluoroquinolones (FQs), especially Pefloxacin (PEF) have been reported to increase risk of Achilles tendon rupture. However, prior studies showed that intrasound therapy (ITR) significantly improved the morphology of the healing tendon. This study aimed to compare the effects of 7, 14 and 21 days intrasound treatment on the mechanical properties and morphology of the Achilles tendon in fifty (50) male Sprague-Dawley rats induced with FQ and randomized into three main categories designated as Normal control (A), Experimental control (B) and Treatment groups (C). All animals in groups B and C were orally administered PEF 400mg/kg in a fixed volume of 2.5 ml/kg daily for 6 consecutive days. The Achilles tendon of both hind limbs in group C were treated with the lowest intensity ITR 5 minutes daily for 7, 14 and 21 consecutive days. All the animals were serially sacrificed on days 8, 15 and 22 and the tendons excised and processed. Data were analyzed with RSTUDIO version 4.0.02 and the level of significance set at 0.05. Kruskal Wallis showed no significant differences (p >0.05) in all the biomechanical parameters across all the groups. Compared with group B, ITR 14 days treatment had the best improvement in all biomechanical variables, though insignificant (p>0.05). In the Intrasound groups, there were significant positive correlations of Nitric Oxide Synthase (NOS) with ultimate tensile stress and tensile load (p= 0.005; p=0.003) respectively. Intrasound treatment to the Achilles tendon for 14 days improved the mechanical properties  and morphology of tendons in Fluoroquinolone-induced tendinopathy.