Therapeutic ultrasound and passive mobilisation improve motor function and reduce inflammation in skeletal muscle of immobilised Wistar rats

Purpose Here we analysed the effects of treatment with therapeutic ultrasound, passive mobilisation and their synergically effects on hind paw' functionality, histomorphometric and immunological aspects in the musculoskeletal tissue in an experimental immobilisation model. Methods Forty male Wistar rats, aged 10 weeks were divided into ( n = 8): Immobilised Group, Free remobilisation, Passive Mobilisation, Therapeutic Ultrasound and Passive Mobilisation and Therapeutic Ultrasound. The animals were immobilised, for 21 consecutive days, with a plaster cast orthosis. Therapeutic Ultrasound with frequency of 1.0 MHZ and intensity of 0.5 w/cm 2 and Passive Mobilisation using degree IV, were performed as treatment. Generalised mixed models and analysis of variance were used for statistical analysis, p ‐value was set as 0.05. The Immobilised Group had loss in motor function and increase in nociceptive threshold. Results Histomorphometry revealed hypotrophy and fibrosis in the muscular tissue, with changes in the muscle fibres, connective tissue and muscle spindles ( p < 0.0001). Animals that underwent both treatments had the best recovery in those aspects. In the inflammatory tests, the immobilisation caused greater amount of tumour necrosis factor alpha, nuclear factor kappa beta and interleukin‐10 ( p < 0.05). Conclusion Treatments synergistically restored motor function, histomorphometric integrity, and immunological balance in the musculoskeletal tissue of the rats after immobilisation. This may indicate that in humans there should be integration of therapies in post‐immobilisation periods. Level of Evidence N/A.