Absorption measurements of cell monolayers relevant to mechanisms of laser phototherapy: reduction or oxidation of cytochrome c oxidase under laser radiation at 632.8 nm.

OBJECTIVE The objective of this work was a further investigation of redox mechanisms of laser phototherapy on the cellular level. BACKGROUND DATA Cytochrome c oxidase, the terminal enzyme of the mitochondrial respiratory chain, is believed to work as the photoacceptor to modulate cellular metabolism in laser phototherapy. MATERIALS AND METHODS The changes in the absorption spectra of HeLa-cell monolayers before and after irradiation at 632.8 nm using fast multi-channel recording were evaluated by the intensity ratio between the peaks at 770 and 670 nm (intensity ratio criterion). RESULTS By the intensity ratio criterion, the irradiation effects (reduction or oxidation of the photoacceptor) depended on the initial redox status of cytochrome c oxidase. The irradiation (three times at 632.8 nm, dose = 6.3 x 103 J/m(2), tau(irrad.) = 10 sec, tau(record.) = 600 msec) of cells initially characterized by relatively oxidized cytochrome c oxidase caused first a reduction of the photoacceptor, and then its oxidation (a bell-shaped curve). The irradiation by the same scheme of the cells with initially relatively reduced cytochrome c oxidase caused first oxidation and then a slight reduction of the enzyme (a curve opposite to the bell-shaped curve). CONCLUSION The experimental results of our work demonstrate that irradiation at 632.8 nm causes either a (transient) relative reduction of the photoacceptor, putatively cytochrome c oxidase, or its (transient) relative oxidation, depending on the initial redox status of the photoacceptor. The maximum in the bell-shaped dose-dependence curve or the minimum of the reverse curve is the turning point between the prevailing of oxidation or reduction processes. Our results are evidence that the bell-shaped dose dependences recorded for various cellular responses are characteristic also for redox changes in the photoacceptor, cytochrome c oxidase.

[1]  T. Karu,et al.  Exact action spectra for cellular responses relevant to phototherapy. , 2005, Photomedicine and laser surgery.

[2]  Stefano Geuna,et al.  Phototherapy promotes regeneration and functional recovery of injured peripheral nerve , 2004, Neurological research.

[3]  L. A. Welser,et al.  Changes in absorbance of monolayer of living cells induced by laser radiation at 633, 670, and 820 nm , 2001, European Conference on Biomedical Optics.

[4]  P. Brzezinski,et al.  Light-induced structural changes in cytochrome c oxidase: implication for the mechanism of electron and proton gating. , 1994, Biochimica et biophysica acta.

[5]  T. Karu,et al.  Primary and secondary mechanisms of action of visible to near-IR radiation on cells. , 1999, Journal of photochemistry and photobiology. B, Biology.

[6]  Kendric C. Smith.  Ten Lectures on Basic Science of Laser Phototherapy , 2007 .

[7]  T. Karu.  Mitochondrial Signaling in Mammalian Cells Activated by Red and Near‐IR Radiation , 2008, Photochemistry and photobiology.

[8]  R. Marcus,et al.  Electron transfers in chemistry and biology , 1985 .

[9]  A. Konstantinov,et al.  Flash‐induced membrane potential generation by cytochrome c oxidase , 1993, FEBS letters.

[10]  Nick Lane,et al.  Power games , 2006 .

[11]  R. Haas,et al.  Effect of low-power laser irradiation on bony implant sites. , 2002, Clinical oral implants research.

[12]  T. Karu,et al.  Absorption measurements of a cell monolayer relevant to phototherapy: reduction of cytochrome c oxidase under near IR radiation. , 2005, Journal of photochemistry and photobiology. B, Biology.

[13]  T. Karu,et al.  Cellular effects of low power laser therapy can be mediated by nitric oxide , 2005, Lasers in surgery and medicine.

[14]  K. Mustafa,et al.  Effect of laser therapy on attachment, proliferation and differentiation of human osteoblast-like cells cultured on titanium implant material. , 2005, Biomaterials.

[15]  DrSci Tiina Karu.  Ten Lectures on Basic Science of Laser Phototherapy , 2007 .

[16]  T. Yonetani,et al.  Resonance Raman spectra of cytochrome oxidase. Evidence for photoreduction by laser photons in resonance with the Soret band. , 1978, Biochimica et biophysica acta.

[17]  Jean Krutmann,et al.  Cellular response to infrared radiation involves retrograde mitochondrial signaling. , 2007, Free radical biology & medicine.

[18]  Britton Chance,et al.  Photobiomodulation Directly Benefits Primary Neurons Functionally Inactivated by Toxins , 2005, Journal of Biological Chemistry.

[19]  Michael Belkin,et al.  Temporal parameters of low energy laser irradiation for optimal delay of post-traumatic degeneration of rat optic nerve , 1989, Brain Research.

[20]  S. Yoshikawa,et al.  Cytochrome oxidase is a possible photo receptor in mitochondria , 1981 .

[21]  Noel T. Whelan,et al.  Therapeutic photobiomodulation for methanol-induced retinal toxicity , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[22]  T. Karu,et al.  A Novel Mitochondrial Signaling Pathway Activated by Visible-to-near Infrared Radiation¶ , 2004, Photochemistry and photobiology.

[23]  Michele Henry,et al.  Mitochondrial signal transduction in accelerated wound and retinal healing by near-infrared light therapy. , 2004, Mitochondrion.

[24]  M. Wong-Riley,et al.  Photobiomodulation partially rescues visual cortical neurons from cyanide-induced apoptosis , 2006, Neuroscience.

[25]  M. Greco,et al.  Specific helium-neon laser sensitivity of the purified cytochrome c oxidase , 2000, International journal of radiation biology.

[26]  G. Moreno,et al.  A study of beating frequency of a single myocardial cell. III. Laser micro-irradiation of mitochondria in the presence of KCN or ATP. , 1979, Experimental cell research.

[27]  R. Shofti,et al.  Low-Energy Laser Irradiation Reduces Formation of Scar Tissue After Myocardial Infarction in Rats and Dogs , 2001, Circulation.