Regeneração do músculo tibial anterior em diferentes períodos após lesão por estimulação elétrica neuromuscular

Abstract

Background: Skeletal muscle injuries may be caused by contraction of the muscle concerned. Objective: To analyze the tibialis anterior muscle at different times following injury induced by electrical stimulation. Method: Male Wistar rats (298.2 ± 16.0g) were divided into two electrically stimulated groups evaluated after three and five days (n= 20) and two control groups, also evaluated after three and five days (n= 14). While stretched, the tibialis anterior muscle was injured by neuromuscular electrical stimulation (90 minutes, 30 Hz, 1 m/s, Ton/Toff 4 s and 4 mA). Three and five days afterwards, the animals were sacrificed and the muscles were removed. Histological sections were cut (10 μm) using a cryostat and were stained with toluidine blue. The body and muscle weights were statistically analyzed using Student's t test (p≤ 0.05). Results: The final body weight was higher than the initial weight for the 3-day control group (288.5 ± 18.3g vs. 308.5 ± 24.3g) and 5-day control group (288.4 ± 15.0g vs. 305.5 ± 20.7g) and lower for the 3-day stimulated group (305.0 ± 13.0g vs. 285.6 ± 13.2g) and 5-day stimulated group (306.1 ± 12.4g vs. 278.4 ± 20.9g). The relative muscle weight in the 5-day stimulated group was lower than in the 5-day control group (0.20 ± 0.001% vs. 0.22 ± 0.01%, respectively). The histological analysis showed variance between the animals regarding the extent and signs of fiber damage and/or regeneration, and the distal region was the most injured. The 3-day stimulated group presented predominance of cell infiltrate and myofilament hypercontraction, while the 5-day stimulated group presented predominance of cell infiltrate, basophils and fibrosis. Conclusion: A period of two days following electrical stimulation was sufficient for showing a difference in the regeneration process. The distal region of the tibialis anterior muscle was more susceptible to injury.

Morphometric and Fractal Analysis of Injured Skeletal Muscle Tissue Subjected to A Combination of Treatments; Cryotherapy and Therapeutic Ultrasound

“…The body weight loss observed in all groups can be attributed to the stress to which the animals were submitted, which could have interfered in the diet and/or metabolism of the animals (Botelho et al, 2007). Moreover, except the Therapeutic ultrasound assists the repair of muscle injury by altering the activity of neutrophils and macrophages involved in the inflammatory phase, accelerating the process of muscle repair, mainly through mechanical effects (Burks et al, 2011).…”

Efeitos do ultra-som terapêutico nas propriedades mecânicas do músculo esquelético após contusão

“…These lesions frequently cause pain and impairments, leading the individuals to look for treatment, very often at physical therapy outpatient clinics 3 . Therapeutic ultrasound (TU) is a commonly used resource for the treatment of disorders affecting the musculoskeletal system, as well as enhancing the tissue recovery in muscular lesions 4 .…”