Morphologic study of different treatments for gastrocnemius muscle contusion in rats

Abstract

ObjectiveEvaluate the effects of ultrasound and stretching in morphology after rat muscle contusion.MethodsMale Wistar rats (n = 35, 8–9 weeks, 271 ± 14 g) were divided into five groups: control group (CG = 3); lesion group (LG = 8); lesion + ultrasound group (LUG = 8); lesion + stretching group (LSG = 8); lesion + ultrasound + stretching group (LUSG = 8). The ultrasound was applied in LUG and LUSG from the third to the seventh day, the dose used was 50% pulsed, 0.5 W/cm2, 5 min. From the tenth until the twenty first day, passive stretching was performed, in four repetitions lasting 30 s each with 30 s of rest. Initial and final body weight, muscle weight and length, number and sarcomere length, muscle fiber cross-sectional area, and percentage of collagen were evaluated after 22 days.ResultsThe final body weight was higher than the initial in all groups. The number of sarcomeres was statistically higher in LSG than LUG and higher in LUSG than LUS and CG; in sarcomere length was higher in LUG when compared with LSG (p < 0.05). The cross sectional area in LG was higher than LSG, and the percentage of collagen was higher in LG when compared with LSG and CG; in LUG when compared with LSG and CG; and in LUSG when compared with CG.ConclusionThe passive stretching protocol induced sarcomerogenesis and antifibrotic effect over the muscle submitted to contusion. Ultrasound, even in association with stretching, was not sufficient to prevent fibrosis in the injured muscle.

miR-24 and miR-122 Negatively Regulate the Transforming Growth Factor-β/Smad Signaling Pathway in Skeletal Muscle Fibrosis

“…Current available treatments for skeletal muscle injury are mainly physiotherapy, such as modifications in activity modes, electoral stimulation, message, ultrasound, or stretching. 36 , 37 , 38 Although patients may return to sports, the fibrotic tissue does not vanish and lacks the elasticity of the native muscle, rendering the muscle susceptible to re-injury. 39 Repeated injury can cause heterotopic ossification, leading to pain and dysfunction of skeletal muscle.…”

Effects of Neuromuscular Electrical Stimulation and Therapeutic Ultrasound on Quadriceps Contracture of Immobilized Rats

“…In contrast, we found an increase in sarcomere length after using therapeutic ultrasound. Previous studies supported that therapeutic ultrasound has the effect of increasing the hamstring muscle length in healthy humans [66] and increasing the sarcomere length in rats after muscle injury [67]. Additionally, therapeutic ultrasound has anti-fibrotic effects in reducing renal fibrosis on experimental hypertensive nephropathy and diabetic nephropathy in mice [68] and in reducing the density of collagen type I, HIF-1α, and α-SMA after prolonged hypoxia-induced cardiac fibrosis in mice [69].…”

Effects of Ultrasound and Stretching on Skeletal Muscle Contusion in Rats: Immunohistochemistry Analysis

“…Experimental animal models contribute to understanding the effects of lengthening stimulus, such as stretching, in the cellular mechanisms of skeletal muscle healing after contusion (Hwang et al, 2006;de Macedo et al, 2014de Macedo et al, , 2016. The involvement of desmin and laminin in force transmission has been described in the literature (De Deyne, 2001).…”

“…The involvement of desmin and laminin in force transmission has been described in the literature (De Deyne, 2001). An increase in sarcomerogenesis and an antifibrotic effect after a stretching protocol of injured rat gastrocnemius has been reported (de Macedo et al, 2014(de Macedo et al, , 2016. Although the proteins desmin and laminin involved in the sarcomerogenesis and muscle healing, have not yet been investigated (Yu & Thornell, 2002;Cação-Benedini et al;Gianelo et al, 2016).…”