Postgraduate Program in Rehabilitation Sciences, Universidade Nove de Julho (UNINOVE), Rua Vergueiro, 349, São Paulo, SP, 01504001, Brazil.
Postgraduate Program in Biophotonics Applied to Health Sciences, Universidade Nove de Julho (UNINOVE), Rua Vergueiro, 349, São Paulo, SP, 01504001, Brazil.
Lasers Med Sci. 2021 Jun;36(4):791-802. doi: 10.1007/s10103-020-03095-y. Epub 2020 Jul 7.
Compensatory hypertrophy (CH) occurs due to excessive mechanical load on a muscle, promoting an increase in the size of muscle fibers. In clinical practice, situations such as partial nerve injuries, denervation, and muscle imbalance caused by trauma to muscles and nerves or diseases that promote the loss of nerve conduction can induce CH in muscle fibers. Photobiomodulation (PBM) has demonstrated beneficial effects on muscle tissue during CH. The aim of the present study was to evaluate the effect of PBM on the inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) as well as type 2 metalloproteinases (MMP-2) during the process of CH due to excessive load on the plantaris muscle in rats. Forty-five Wistar rats weighing 250 g were divided into three groups: control group (n = 10), hypertrophy (H) group (n = 40), and H + PBM group (n = 40). CH was induced through the ablation of synergist muscles of the plantaris muscle. The tendons of the gastrocnemius and soleus muscles were isolated and sectioned to enable the partial removal of each of muscle. The preserved plantaris muscle below the removed muscles was submitted to excessive functional load. PBM was performed with low-level laser (AsGaAl, λ = 780 nm; 40 mW; energy density: 10 J/cm; 10 s on each point, 8 points; 3.2 J). Animals from each group were euthanized after 7 and 14 days. The plantaris muscles were carefully removed and sent for analysis of the gene and protein expression of IL-6 and TNF-α using qPCR and ELISA, respectively. MMP-2 activity was analyzed using zymography. The results were submitted to statistical analysis (ANOVA + Tukey's test, p < 0.05). The protein expression analysis revealed an increase in IL-6 levels in the H + PBM group compared to the H group and a reduction in the H group compared to the control group. A reduction in TNF-α was found in the H and H + PBM groups compared to the control group at 7 days. The gene expression analysis revealed an increase in IL-6 in the H + PBM group compared to the H group at 14 days as well as an increase in TNF-α in the H + PBM group compared to the H group at 7 days. Increases in MMP-2 were found in the H and H + PBM groups compared to the control group at both 7 and 14 days. Based on findings in the present study, it is concluded that PBM was able to modulate pro-inflammatory cytokines that are essential for the compensatory hypertrophy process. However, it has not shown a modulation effect directly in MMP-2 activity during the same period evaluated.
代偿性肥大（CH）是由于肌肉承受过度的机械负荷而发生的，会促进肌肉纤维的大小增加。在临床实践中，部分神经损伤、去神经支配以及肌肉和神经损伤引起的肌肉失衡或促进神经传导丧失的疾病等情况，可导致肌肉纤维发生 CH。光生物调节（PBM）已证明对 CH 过程中的肌肉组织具有有益的影响。本研究旨在评估 PBM 对大鼠比目鱼肌过度负荷引起的 CH 过程中炎症细胞因子白细胞介素-6（IL-6）和肿瘤坏死因子-α（TNF-α）以及 2 型金属蛋白酶（MMP-2）的影响。45 只体重为 250g 的 Wistar 大鼠分为三组：对照组（n=10）、肥大组（H 组）（n=40）和 H+PBM 组（n=40）。CH 通过比目鱼肌协同肌的消融来诱导。分离并切断腓肠肌和比目鱼肌的肌腱，以分别切除每个肌肉。保留在切除肌肉下方的比目鱼肌承受过度的功能负荷。采用低水平激光（AsGaAl，λ=780nm；40mW；能量密度：10J/cm；每个点 10s，8 个点；3.2J）进行 PBM。每组动物在 7 天和 14 天后处死。小心取出比目鱼肌，并分别通过 qPCR 和 ELISA 分析基因和蛋白表达，以分析 IL-6 和 TNF-α的表达。通过酶谱法分析 MMP-2 的活性。结果进行统计学分析（ANOVA+Tukey 检验，p<0.05）。蛋白表达分析显示，与 H 组相比，H+PBM 组的 IL-6 水平升高，与对照组相比，H 组的 IL-6 水平降低。与对照组相比，H 组和 H+PBM 组在第 7 天 TNF-α 降低。基因表达分析显示，与 H 组相比，H+PBM 组在第 14 天的 IL-6 升高，与 H 组相比，H+PBM 组在第 7 天的 TNF-α 升高。与对照组相比，H 组和 H+PBM 组在第 7 天和第 14 天都有 MMP-2 的增加。基于本研究的结果，可以得出结论，PBM 能够调节对代偿性肥大过程至关重要的促炎细胞因子。然而，它在同一时期评估的 MMP-2 活性中没有表现出直接的调节作用。
