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(Reference retrieved automatically from SciELO through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Regeneration of the tibialis anterior muscle at different times following injury induced by neuromuscular electrical stimulation

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Author(s):
AP Botelho [1] ; FA Facio [2] ; VB Minamoto [3]
Total Authors: 3
Affiliation:
[1] Universidade Metodista de Piracicaba. Faculdade de Ciências da Saúde. Programa de Pós-Graduação em Fisioterapia - Brasil
[2] Universidade Metodista de Piracicaba. Faculdade de Ciências da Saúde. Programa de Pós-Graduação em Fisioterapia - Brasil
[3] Universidade Metodista de Piracicaba. Faculdade de Ciências da Saúde. Programa de Pós-Graduação em Fisioterapia - Brasil
Total Affiliations: 3
Document type: Journal article
Source: BRAZILIAN JOURNAL OF PHYSICAL THERAPY; v. 11, n. 2, p. 99-104, 2007-04-00.
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. (AU)