Therapeutic effects of LIPUS on the elasticity of injured tendons: animal experiment

Abstract

Abstract This paper aims to explore the efficacy and duration of low-intensity pulsed ultrasound (LIPUS) treatment in improving the elastic properties of injured tendons through animal experiments. 48 healthy 3-month-old New Zealand white rabbits (weight 2.5-3.0 kg) were randomly divided into the Control group (n = 9) and model group (n = 39). The rabbits in the model group were injected with 0.2ml PGE2 mixed solution (concentration: 500 ng/0.2ml) into the Achilles tendon 2cm above the calcaneus, once a week, for 4 weeks, to build the Achilles tendon injury model. The Control group was injected with the same volume of PBS solution. Three rabbits were randomly selected from the Control and model groups for model validation, the model group was randomly divided into the Model (n = 6) and LIPUS (n = 30) groups. Then the LIPUS was randomly divided into the LIPUS1 (n = 6), LIPUS4 (n = 6), LIPUS7 (n = 6), LIPUS14 (n = 6), and LIPUS28 (n = 6) subgroups. Following interventions on days 1, 4, 7, 14, and 28, tendon elasticity was assessed by shear wave elastography (SWE). The elastic modulus of the Model, LIPUS1, and LIPUS4 groups exhibited a significant decrease compared to the Control group during the early stages of treatment. With prolonged treatment duration, the elastic modulus of LIPUS groups gradually increased. By day 7, no statistically significant difference in elastic modulus existed between the LIPUS7 and Control groups, indicating that LIPUS treatment had successfully restored the Achilles tendon’s elasticity to a healthy state. In summary, LIPUS therapy demonstrates the potential to effectively ameliorate the elastic properties of injured Achilles tendons.