Low‐level laser therapy associated with high intensity resistance training on cardiac autonomic control of heart rate and skeletal muscle remodeling in wistar rats. Issue 10 (1st November 2014)

• Record Type: Journal Article
• Authors: Paolillo, Fernanda Rossi; Arena, Ross; Dutra, Daniela Bassi; de Cassia Marqueti Durigan, Rita; de Araujo, Heloisa Selistre; de Souza, Hugo Celso Dutra; Parizotto, Nivaldo Antonio; Cipriano, Gerson; Chiappa, Gaspar; Borghi‐Silva, Audrey
• Is Part Of: Lasers in surgery and medicine. Volume 46:Issue 10(2014)
• Page Start: 796
• Page End: 803
• Publication Date: 2014-11-01
• Subjects: Lasers in medicine -- Periodicals; Lasers in surgery -- Periodicals; 617
• DOI: 10.1002/lsm.22298
• Languages: English
• ISSNs: 0196-8092

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="lsm22298-sec-0001" sec-type="section"> <title>Background and Objective</title> <p>Phototherapy plus dynamic exercise can enhance physical performance and improve health. The aim of our study was to evaluate the effect of low‐level laser therapy (LLLT) associated with high intensity resistance training (HIT) on cardiac autonomic and muscle metabolic responses in rats.</p> </sec> <sec id="lsm22298-sec-0002" sec-type="section"> <title>Study Design/Materials and Methods</title> <p>Forty Wistar rats were randomized into 4 groups: sedentary control (CG), HIT, LLLT and HIT + LLLT. HIT was performed 3 times/week for 8 weeks with loads attached to the tail of the animal. The load was gradually increased by 10% of body mass until reaching a maximal overload. For LLLT, irradiation parameters applied to the tibialis anterior (TA) muscle were as follows: infrared laser (780 nm), power of 15 mW for 10 seconds, leading to an irradiance of 37.5 mW/cm<sup>2</sup>, energy of 0.15 J per point and fluency of 3.8 J/cm<sup>2</sup>. Blood lactate (BL), matrix metalloproteinase gelatinase A (MMP<sub>−2</sub>) gene expression and heart rate variability (HRV) indices were performed.</p> </sec> <sec id="lsm22298-sec-0003" sec-type="section"> <title>Results</title> <p>BL significantly increased after 8‐weeks for HIT, LLLT and HIT + LLLT groups. However, peak lactate when normalized by maximal load was significantly reduced for both HIT and HIT + LLLT groups (<italic>P</italic><0.05). MMP<sub>−2</sub> in the active form was significantly increased after HIT, LLLT and HIT + LLLT compared tom the CG (<italic>P</italic><0.05). There was a significant reduction in low frequency [LF (ms<sup>2</sup>)] and increase in high frequency [HF (un)] and HF (ms<sup>2</sup>)] for the HIT, LLLT and HIT + LLLT groups compared with the CG (<italic>P </italic>< 0.05). However, the LF/HF ratio was further reduced in the LLLT and HIT + LLLT groups compared to the CG and HIT group (<italic>P </italic>< 0.05).</p> </sec> <sec id="lsm22298-sec-0004" sec-type="section"> <title>Conclusion</title> <p>These results provide evidence for the positive benefits of LLLT and HIT with respect to enhanced muscle metabolic and cardiac autonomic function in Wistar rats. Lasers Surg. Med. 46:796–803, 2014. © 2014 Wiley Periodicals, Inc.</p> </sec> </abstract>