Effect of Therapeutic Ultrasound on the Recovery of the Tibialis Anterior Muscle in Remobilized Wistar Rats after a Period of Immobilization: An Analysis Using the Pathological Index

Background.Prolonged joint immobilization causes muscle hypotrophy and joint stiffness, which worsen as the immobilization time increases.Muscle remobilization is essential to restore muscle mass and activity as soon as possible.There are various treatments for muscle remobilization, but therapeutic ultrasound has proved to be a promising technique, with thermal and athermic actions, generating possibilities for increasing tissue extensibility and cell metabolism, helping with the anabolic effects of static stretching.Objective.To evaluate the histopathological changes in the tibialis anterior muscle of Wistar rats after remobilization using therapeutic ultrasound, using the histopathological index.Methods.21 male Wistar rats were used, divided into 3 groups (n = 7): immobilization group, immobilization and free remobilization group, immobilization and remobilization with ultrasound group.Immobilization was carried out with the knee flexed at 120° and total ankle plantiflexion for three weeks.Ultrasound was used at a frequency of 1.0 MHz with an intensity of 0.5 w/cm 2 , lasting 2 minutes on the knee and a further 2 minutes on the ankle.Analyses were carried out using the histopathological index to measure the level of alterations and lesions in the muscle tissue, classifying them as severe, moderate or mild.Conclusions.It was concluded that the anabolic stimulus of ultrasound was favorable to the trophic recovery of muscle tissue.