Low-level laser therapy (904 nm) counteracts motor deficit of mice hind limb following skeletal muscle injury caused by snakebite-mimicking intramuscular venom injection

• Grant number: 16/13579-5
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: September 01, 2016
• End date: February 28, 2017
• Field of knowledge: Health Sciences - Medicine
• Principal Investigator: Maria Alice da Cruz Hofling
• Grantee: Maria Alice da Cruz Hofling
• Host Institution: Instituto de Biologia (IB). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Myotoxins present in Bothrops venom disrupt the sarcolemma of muscle fibers 25 leading to the release of sarcoplasmic proteins and loss of muscle homeostasis. Myonecrosis 26 and tissue anoxia induced by vascularization impairment can lead to amputation or motor 27 functional deficit. The objective of this study was to investigate the dynamic behavior of 28 motor function in mice subjected to injection of Bothrops jararacussu venom (Bjssu) and 29 exposed to low-level laser therapy (LLLT). Male Swiss mice received Bjssu injection (830 30 ¼g/kg) into the medial portion of the right gastrocnemius muscle. Three hours later the 31 injected region was irradiated with diode semiconductor Gallium Arsenide (GaAs - 904 nm, 4 32 J/cm²) laser following by irradiation at 24, 48 and 72 hours. Saline injection (0.9% NaCl) was 33 used as control. Gait analysis was performed 24 hours before Bjssu injection and at every 34 period post-Bjssu using CatWalk method. Data from spatiotemporal parameters Stand, 35 Maximum Intensity, Swing, Swing Speed, Stride Length and Step Cycle were considered. 36 The period of 3 hours post venom-induced injury was considered critical for all parameters 37 evaluated in the right hindlimb. Differences (p<0.05) were concentrated in venom and venom 38 + placebo laser groups during the 3 hours post-injury period, in which the values of stand of 39 most animals were null. After this period, the gait characteristics were re-established for all 40 parameters. The venom + laser group kept the values at 3 hours post-Bjssu equal to that at 24 41 hours before Bjssu injection indicating that the GaAs laser therapy improved spatially and 42 temporally gait parameters at the critical injury period caused by Bjssu. This is the first study 43 to analyze with cutting edge technology the gait functional deficits caused by snake 44 envenoming and gait gains produced by GaAs laser irradiation. In this sense, the study fills a 45 gap on the field of motor function after laser treatment following snake envenoming. (AU)