Photobiomodulation also known as low-level laser (or light) therapy (LLLT), has been known for almost 50 years but still has not gained widespread acceptance, largely due to uncertainty about the molecular, cellular, and tissular mechanisms of action. However, in recent years, much knowledge has been gained in this area, which will be summarized in this review. One of the most important chromophores is cytochrome c oxidase (unit IV in the mitochondrial respiratory chain), which contains both heme and copper centers and absorbs light into the near-infrared region. The leading hypothesis is that the photons dissociate inhibitory nitric oxide from the enzyme, leading to an increase in electron transport, mitochondrial membrane potential, and adenosine triphosphate production. Another hypothesis concerns light-sensitive ion channels that can be activated allowing calcium (Ca2+) to enter the cell. After the initial photon absorption events, numerous signaling pathways are activated via reactive oxygen species, cyclic AMP, NO, and Ca2+, leading to activation of transcription factors. These transcription factors can lead to increased expression of genes related to protein synthesis, cell migration and proliferation, anti-inflammatory signaling, anti-apoptotic proteins, and antioxidant enzymes. Stem cells and progenitor cells appear to be particularly susceptible to LLLT.

中文翻译：

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光生物调节或低强度光疗法的拟议机制

光生物调节也称为低强度激光（或光）疗法 (LLLT)，已为人所知近 50 年，但仍未获得广泛接受，这主要是由于分子、细胞和组织作用机制的不确定性。然而，近年来，在该领域已经获得了很多知识，本综述将对其进行总结。最重要的发色团之一是细胞色素 c 氧化酶（线粒体呼吸链中的单元 IV），它包含血红素和铜中心，并将光吸收到近红外区域。主要假设是光子将抑制性一氧化氮与酶解离，导致电子传递、线粒体膜电位和三磷酸腺苷生成增加。另一个假设涉及光敏离子通道，该通道可以被激活，从而允许钙 (Ca2+) 进入细胞。在最初的光子吸收事件之后，许多信号通路通过活性氧、环 AMP、NO 和 Ca2+ 被激活，从而导致转录因子的激活。这些转录因子可导致与蛋白质合成、细胞迁移和增殖、抗炎信号、抗凋亡蛋白和抗氧化酶相关的基因表达增加。干细胞和祖细胞似乎对 LLLT 特别敏感。这些转录因子可导致与蛋白质合成、细胞迁移和增殖、抗炎信号、抗凋亡蛋白和抗氧化酶相关的基因表达增加。干细胞和祖细胞似乎对 LLLT 特别敏感。这些转录因子可导致与蛋白质合成、细胞迁移和增殖、抗炎信号、抗凋亡蛋白和抗氧化酶相关的基因表达增加。干细胞和祖细胞似乎对 LLLT 特别敏感。