Effect of phototherapy on skeletal muscle regeneration of senile rats after acute injury

• Grant number: 14/13109-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2014
• End date: September 30, 2015
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Raquel Agnelli Mesquita Ferrari
• Grantee: Daniel Victor Demilio Barbosa
• Host Institution: Universidade Nove de Julho (UNINOVE). Campus Vergueiro. São Paulo , SP, Brazil

Abstract

Aging is characterized by a decrease in physiological, biochemical functions, morphological and cellular changes which correlate with the progressive decline in muscle mass, strength and quality of execution of the movement. The low-level laser (LLL) has shown positive effects during the skeletal muscle repair by inducing increased production of adenosine triphosphate (ATP), stimulation of angiogenesis, activation and proliferation of satellite cells, modulating the production of cytokines and growth factors during this process, reducing the resolution time and improving quality. The aim of present study is to evaluate the effects of LLL on the inflammatory infiltrate, edema, myonecrosis and on new muscle fibers in skeletal muscles of senile rats after cryoinjury in the tibialis anterior muscle. The animals will be divided into 04 groups: (1) Control, (2) Cryolesioned without treatment, (3) and Cryolesioned treated with LBP and (4) no injury and irradiated with LLL. The analysis will be performed at 1, 3, 7 and 14 days. Cryoinjury was performed on the belly of the tibialis anterior (TA) muscle. LLLT will be performed daily using the GaAlAs laser (780nm) with a beam spot of 0.4 cm2, an output power of 40mW, energy density of 10J/cm2 for 10 seconds, on each of 8 points around injury region, totalizing 3,2J per treatment. After sacrifice, the TA muscles will be removed for analysis of the morphological aspects by H & E staining. Data will be analyzed statistically.