Cressoni Marcella Dalla Costa, Dib Giusti Helena Hanna Khalil, Casarotto Raquel Aparecida, Anaruma Carlos Alberto
Department of Physiotherapy, University of São Paulo, São Paulo, Brazil.
Photomed Laser Surg. 2008 Oct;26(5):461-6. doi: 10.1089/pho.2007.2150.
This study aims to investigate the effects of low-level laser therapy (LLLT) on muscle regeneration. For this purpose, the anterior tibialis muscle of 48 male Wistar rats received AlGaInP laser treatment (785 nm) after surgically-induced injury.
Few studies have been conducted on the effects of LLLT on muscle regeneration at different irradiation doses.
The animals were randomized into four groups: uninjured rats (UN); uninjured and laser-irradiated rats (ULI); injured rats (IN); and injured and laser-irradiated rats (ILI). The direct contact laser treatment was started 24 h after surgery. An AlGaInP diode laser emitting 75 mW of continuous power at 785 nm was used for irradiation. The laser probe was placed at three treatment points to deliver 0.9 J per point, for a total dose of 2.7 J per treatment session. The animals were euthanized after treatment sessions 1, 2, and 4. Mounted sections were stained with hematoxylin and eosin and used for quantitative morphological analysis, in which the number of leukocytes and fibroblasts were counted over an area of 4480 mum(2). The data were statistically analyzed by analysis of variance (ANOVA) and the Bonferroni t-test.
Quantitative data showed that the number of both polymorphonuclear and mononuclear leukocytes in the inflammatory infiltrate at the injury site was smaller in the ILI(1), ILI(2), and ILI(4) subgroups compared with their respective control subgroups (IN(1), IN(2), and IN(4)) for sessions 1, 2, and 4, respectively (p < 0.05). On the other hand, the number of fibroblasts increased after the fourth treatment session (p < 0.05). With regard to the regeneration of muscle fibers following injury, only after the fourth treatment session was it possible to find muscle precursor cells such as myoblasts and some myotubes in the ILI(4) subgroup.
During the acute inflammatory phase, the AlGaInP laser treatment was found to have anti-inflammatory effects, reducing the number of leukocytes at the injury site and accelerating the regeneration of connective tissue.
本研究旨在探讨低强度激光疗法（LLLT）对肌肉再生的影响。为此，48只雄性Wistar大鼠的胫骨前肌在手术诱导损伤后接受了铝镓铟磷激光治疗（785纳米）。
关于不同照射剂量的LLLT对肌肉再生影响的研究较少。
将动物随机分为四组：未受伤大鼠（UN）；未受伤且接受激光照射的大鼠（ULI）；受伤大鼠（IN）；受伤且接受激光照射的大鼠（ILI）。手术后24小时开始直接接触式激光治疗。使用一台在785纳米波长发射75毫瓦连续功率的铝镓铟磷二极管激光器进行照射。将激光探头放置在三个治疗点，每个点输送0.9焦耳，每次治疗总剂量为2.7焦耳。在第1、2和4次治疗后对动物实施安乐死。将切片用苏木精和伊红染色，用于定量形态学分析，在4480平方微米的区域内对白细胞和成纤维细胞数量进行计数。数据采用方差分析（ANOVA）和Bonferroni t检验进行统计学分析。
定量数据显示，在第1、2和4次治疗时，ILI(1)、ILI(2)和ILI(4)亚组损伤部位炎症浸润中的多形核白细胞和单核白细胞数量分别比各自的对照亚组（IN(1)、IN(2)和IN(4)）少（p < 0.05）。另一方面，在第四次治疗后成纤维细胞数量增加（p < 0.05）。关于损伤后肌肉纤维的再生，仅在第四次治疗后，才有可能在ILI(4)亚组中发现成肌细胞和一些肌管等肌肉前体细胞。
在急性炎症期，发现铝镓铟磷激光治疗具有抗炎作用，可减少损伤部位的白细胞数量并加速结缔组织的再生。
