Low-level light therapy (LLLT) is emerging as a promising therapeutic approach to modulate the biochemical and molecular processes within living cells. LLLT is known to produce local and systemic effects; therefore, immune cells in local tissues or in the circulation are affected by light. However, this specific effect remains weakly explored. In this study, the effect of red (650 nm) and NIR (808 nm) light on phagocytosis (respiratory burst), cytokine expression, mitochondrial activity, ROS generation, Ca²⁺ influx and membrane depolarization in macrophages in vitro is investigated. Both the phagocytic capacity and adhesion of macrophages strongly (~2.5 times) increased in the first hours after exposure to light in a dose-dependent manner. The light-evoked upregulation of phagocytosis is found to be less efficient than the maximal pharmacologically induced enhancement of ~3.2 times. Also, red/NIR light reduces the production of pro-inflammatory cytokines and activates the secretion of anti-inflammatory cytokines by several times in activated macrophages. At the same time, the viability shows a biphasic dose response: it increases after irradiation with lower doses (0.3–1 J cm⁻²) and decreases after treatment with higher doses (18–30 J cm⁻²), which is apparently associated with the upregulation of ROS generation, followed by an increase in the mitochondrial activity.

中文翻译：

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红光/近红外光调制的巨噬细胞：吞噬作用、细胞因子、线粒体活性、Ca2+ 流入、膜去极化和活力

低水平光疗法 (LLLT) 正在成为一种有前途的治疗方法，可调节活细胞内的生化和分子过程。已知 LLLT 会产生局部和全身效应；因此，局部组织或循环中的免疫细胞会受到光的影响。然而，这种特定的影响仍然没有得到充分探索。在这项研究中，红光 (650 nm) 和 NIR (808 nm) 光对吞噬作用（呼吸爆发）、细胞因子表达、线粒体活性、ROS 生成、Ca ^2+的影响研究了体外巨噬细胞的流入和膜去极化。在暴露于光后的最初几个小时内，巨噬细胞的吞噬能力和粘附力均以剂量依赖性方式显着增加（约 2.5 倍）。发现吞噬作用的光诱发上调效率低于最大药理学诱导的约 3.2 倍增强。此外，红光/近红外光可减少促炎细胞因子的产生，并在活化的巨噬细胞中多次激活抗炎细胞因子的分泌。同时，活力表现出双相剂量反应：在较低剂量 (0.3-1 J cm ^-2 ) 照射后它会增加，在较高剂量 (18-30 J cm ^{-2 ) 照射后降低})，这显然与 ROS 生成的上调有关，然后是线粒体活性的增加。