Baptista Juliana, Martins Manoela Domingues, Pavesi Vanessa Christina Santos, Bussadori Sandra Kalil, Fernandes Kristianne Porta Santos, Pinto Júnior Décio dos Santos, Ferrari Raquel Agnelli Mesquita
Universidade Nove de Julho- UNINOVE, São Paulo, Brazil.
Photomed Laser Surg. 2011 Jan;29(1):11-7. doi: 10.1089/pho.2009.2737. Epub 2010 Aug 11.
The aim of the present study was to determine the effect of GaAlAs low-level laser therapy (LLLT) on collagen IV remodeling of the tibialis anterior (TA) muscle in rats after cryolesion.
Considerable interest exists in skeletal muscle regeneration in situations such as repair after exercise-induced muscle injury, after muscle transplantation, in muscular dystrophy, exercise-induced muscle injury, and the recovery of strength after atrophy due to disuse. A number of studies have demonstrated the potential of LLLT in facilitating the muscle-healing process; however, no consensus is found in the literature regarding the best laser-irradiation parameters.
Adult male Wistar rats (n = 45) were used and randomly divided into three groups: control (n = 5); nontreated cryolesioned group (n = 20), and LLLT-cryolesioned group (n = 20). The cryolesioned groups were analyzed at 1, 7, 14, and 21 days after the injury procedure. Laser irradiation was performed 3 times per week on the injured region by using the GaAlAs laser (660 nm; beam spot of 0.04 cm(2), output power of 20 mW, power density of 500 mW/cm(2), and energy density of 5 J/cm(2), for 10 sec). The muscles were removed, frozen, cryosectioned, and then stained with hematoxylin-eosin for the visualization of general morphology or used for immunohistochemical analysis of collagen IV.
It was demonstrated that LLLT promotes an increase in collagen IV immunolabeling in skeletal muscle in the first 7 days after acute trauma caused by cryoinjury, but does not modify the duration of the tissue-repair process. Even with LLLT, the injured muscle tissue needs ∼21 days to achieve the same state of organization as that in the noninjured muscle.
The collagen IV content is modulated in regenerating skeletal muscle under LLLT, which might be associated with better tissue outcome, although the histologic analysis did not detect tissue improvement in the LLLT group.
本研究旨在确定砷化镓铝低强度激光疗法（LLLT）对冷冻损伤后大鼠胫前肌（TA）中IV型胶原蛋白重塑的影响。
在运动诱导的肌肉损伤修复、肌肉移植后、肌营养不良、运动诱导的肌肉损伤以及废用性萎缩后力量恢复等情况下，骨骼肌再生备受关注。多项研究已证明LLLT在促进肌肉愈合过程中的潜力；然而，关于最佳激光照射参数，文献中尚未达成共识。
使用成年雄性Wistar大鼠（n = 45），随机分为三组：对照组（n = 5）；未治疗的冷冻损伤组（n = 20），以及LLLT - 冷冻损伤组（n = 20）。在损伤操作后的1、7、14和21天对冷冻损伤组进行分析。使用砷化镓铝激光（660 nm；光斑为0.04 cm²，输出功率20 mW，功率密度500 mW/cm²，能量密度5 J/cm²，照射10秒）每周对损伤区域进行3次激光照射。取出肌肉，冷冻，进行冰冻切片，然后用苏木精 - 伊红染色以观察一般形态，或用于IV型胶原蛋白的免疫组织化学分析。
结果表明，LLLT可促进冷冻损伤引起的急性创伤后前7天骨骼肌中IV型胶原蛋白免疫标记增加，但不改变组织修复过程的持续时间。即使使用LLLT，损伤的肌肉组织仍需要约21天才能达到与未损伤肌肉相同的组织状态。
在LLLT作用下，再生骨骼肌中的IV型胶原蛋白含量受到调节，这可能与更好的组织结果相关，尽管组织学分析未检测到LLLT组的组织改善。
