Zungu Innocent L, Hawkins Evans Denise, Abrahamse Heidi
Laser Research Group, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.
Photochem Photobiol. 2009 Jul-Aug;85(4):987-96. doi: 10.1111/j.1751-1097.2008.00523.x. Epub 2009 Feb 13.
Laser irradiation has proved to be very efficient in speeding and improving the quality of healing in pathological conditions of diverse etiologies. However, the mechanisms by which the beneficial effects are attained are not clear. Mitochondria are the primary phototargets during irradiation. The study aimed to establish if laser irradiation had an effect on hypoxic and acidotic cells. The study also aimed to use existing information regarding the possible mechanism of action (established in wounded cells) and apply these principles to acidic and hypoxic irradiated cells to determine whether laser has a stimulatory or inhibitory effect. Cell cultures were modified to simulate conditions of hypoxia (hypoxic gas mixture 95% N2 and 5% O2) and acidosis (pH 6.7) whereas the central scratch model was used to simulate a wound. Cells were irradiated with a helium-neon (632.8 nm, 3 mW cm(-2)) laser using 5 or 16 J cm(-2) on days 1 and 4. Mitochondrial responses were measured 1 or 24 h after laser irradiation by assessing changes in mitochondrial membrane potential (MMP), cyclic AMP, intracellular Ca2+ and adenosine triphosphate (ATP) cell viability. Hypoxia and acidosis significantly reduced MMP when compared with normal nonirradiated control cells. Wounded, hypoxic and acidotic cells irradiated with 5 J cm(-2) showed an increase in mitochondrial responses when compared with nonirradiated cells while 16 J cm(-2) showed a significant decrease. The study confirmed that laser irradiation with 5 J cm(-2) stimulated an increase in intracellular Ca2+ which resulted in an increase in MMP, ATP and cAMP, which ultimately results in photobiomodulation to restore homeostasis of injured cells.
事实证明，激光照射在加速和改善各种病因的病理状况下的愈合速度及质量方面非常有效。然而，实现这些有益效果的机制尚不清楚。线粒体是照射过程中的主要光靶点。该研究旨在确定激光照射对缺氧和酸中毒细胞是否有影响。该研究还旨在利用有关（在受伤细胞中已确立的）可能作用机制的现有信息，并将这些原理应用于酸性和缺氧照射细胞，以确定激光是具有刺激作用还是抑制作用。对细胞培养进行改良以模拟缺氧（95% N₂ 和 5% O₂ 的缺氧气体混合物）和酸中毒（pH 6.7）的条件，而使用中央划痕模型来模拟伤口。在第 1 天和第 4 天，用氦氖（632.8 nm，3 mW cm⁻²）激光以 5 或 16 J cm⁻² 的剂量照射细胞。在激光照射后 1 或 24 小时，通过评估线粒体膜电位（MMP）、环磷酸腺苷（cAMP）、细胞内 Ca²⁺ 和三磷酸腺苷（ATP）的变化以及细胞活力来测量线粒体反应。与未照射的正常对照细胞相比，缺氧和酸中毒显著降低了 MMP。与未照射的细胞相比，用 5 J cm⁻² 照射的受伤、缺氧和酸中毒细胞的线粒体反应有所增加，而 16 J cm⁻² 则显示出显著下降。该研究证实，5 J cm⁻² 的激光照射刺激细胞内 Ca²⁺ 增加，从而导致 MMP、ATP 和 cAMP 增加，最终导致光生物调节以恢复受损细胞的稳态。
