Low level light therapy uses light of specific wavelengths in red and near-infrared spectral range to treat various pathological conditions. This light is able to modulate biochemical cascade reactions in cells that can have important health implications. In this study, the effect of low intensity light at 650, 808 and 1064 nm on neurons and two types of cancer cells (neuroblastoma and HeLa) is reported, with focus on the photoinduced change of intracellular level of Ca²⁺ ions and corresponding signaling pathways. The obtained results show that 650 and 808 nm light promotes intracellular Ca²⁺ elevation regardless of cell type, but with different dynamics due to the specificities of Ca²⁺ regulation in neurons and cancer cells. Two origins responsible for Ca²⁺ elevation are determined to be: influx of exogenous Ca²⁺ ions into cells and Ca²⁺ release from endoplasmic reticulum. Our investigation of the related cellular processes shows that light-induced membrane depolarization is distinctly involved in the mechanism of Ca²⁺ influx. Ca²⁺ release from endoplasmic reticulum activated by reactive oxygen species generation is considered as a possible light-dependent signaling pathway. In contrast to the irradiation with 650 and 808 nm light, no effects are observed under 1064 nm irradiation. We believe that the obtained insights are of high significance and can be useful for the development of drug-free phototherapy.

弱光疗法使用红色和近红外光谱范围内特定波长的光来治疗各种病理状况。这种光能够调节细胞中的生化级联反应，对健康有重要影响。在这项研究中，报道了650、808和1064 nm的低强度光对神经元和两种类型的癌细胞（神经母细胞瘤和HeLa）的影响，重点是光诱导的细胞内Ca ²⁺离子水平的变化和相应的信号传导途径。所得结果表明，无论细胞类型如何，650和808 nm的光均会促进细胞内Ca ^2+的升高，但由于Ca ²⁺的特异性而具有不同的动力学。调节神经元和癌细胞。确定造成Ca ²⁺升高的两个起源是：外源Ca ²⁺离子流入细胞和Ca ²⁺从内质网释放。我们对相关细胞过程的研究表明，光诱导的膜去极化明显参与Ca ^2+内流的机制。钙²⁺从内质网释放被活性氧生成激活的释放被认为是可能的光依赖性信号传导途径。与用650和808 nm的光照射相反，在1064 nm的照射下没有观察到任何影响。我们认为，所获得的见解具有高度意义，并且对开发无药物光疗很有用。