Effect of photobiomodulation on connective tissue remodeling and regeneration of skeletal muscle in elderly rats

Author(s)

de Brito, Adriana ^[1] ; Alves, Agnelo Neves ^[1] ; Ribeiro, Beatriz Guimaraes ^[2] ; Emilio Barbosa, Daniel Victor D. ^[3] ; Ramos Magalhaes, Erick Moreno ^[3] ; Santos Fernandes, Kristianne Porta ^[1] ; Bussadori, Sandra Kalil ^{[2, 1]} ; Goulardins, Juliana Barbosa ^[1] ; Mesquita-Ferrari, Raquel Agnelli ^{[2, 1]}

Affiliation

^[1] Univ Nove Julho UNINOVE, Postgrad Program Biophoton Appl Hlth Sci, Rua Vergueiro 235-249, BR-01504001 Sao Paulo, SP - Brazil

^[2] UNINOVE, Postgrad Program Rehabil Sci, Sao Paulo, SP - Brazil

^[3] UNINOVE, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Lasers in Medical Science; v. 33, n. 3, p. 513-521, APR 2018.
• Web of Science Citations: 2

Abstract

The purpose of this study was to evaluate the effects of low-level laser therapy (LLLT) on morphological aspects, IL-6 and IL-1 beta expressions, as well as the distribution and organization of collagen in the tibialis anterior (TA) muscle of elderly rats submitted to cryoinjury. Histological photomicrographs were taken of TA muscles stained with HE and picrosirius red. Immunohistochemistry was used for the evaluation of IL-6 and IL-1 beta. Male Wistar rats, aged 20 months, were distributed into three groups: (1) control animals not injured or treated with LLLT (n = 5), (2) cryoinjury without LLLT treatment (n = 15), and (3) cryoinjury treated with infrared LLLT (n = 15). LLLT was applied to the TA 2 h after of the injury induction and consisted of daily applications until the sacrifice (1, 3, and 7 days). The following parameters were used: lambda = 780 nm, power density 1 W/cm(2), output power 40 mW, 10 s per point, 8 points, and 3.2 J of total energy. In the histomorphological analysis, the treated group exhibited a significant decrease in inflammatory infiltrate (p < 0.001) as well as an increase immature fibers and new blood vessels at 7 days compared to the untreated group (p < 0.05). Furthermore, treatment induced a better collagen distribution and organization at 7 days in comparison to the untreated group (p < 0.05). In conclusion, LLLT demonstrated a modulatory effect on the muscle repair process in elderly animals with regard to the collagen remodeling and morphological aspects of muscle tissue. (AU)

• FAPESP's process: 14/12381-1 - Comparative analysis of the effect of previous laser therapy associated or not to post treatment on the modulation of inflammatory cytokines, oxidative stress and the determination of muscle fiber type after acute injury
• Grantee: Raquel Agnelli Mesquita Ferrari
• Support Opportunities: Regular Research Grants