Two different mechanisms of low-intensity laser photobiological effects on Escherichia coli

Background and Objective: Laser therapy is a new approach applicable in different medical fields when bone loss occurs, including orthopedics and dentistry. It has also been used to induce soft-tissue healing, for pain relief, bone, and nerve regeneration. With regard to bone synthesis, laser exposure has been shown to increase osteoblast activity and decrease osteoclast number, by inducing alkaline phosphatase (ALP), osteopontin, and bone sialoprotein expression. Studies have investigated the effects of continuous or pulsed laser irradiation, but no data are yet available on the properties of superpulsed laser irradiation. This study thus aimed to investigate the effect of superpulsed laser irradiation on osteogenic activity of human osteoblast-like cells, paying particular attention to investigating the molecular mechanisms underlying the effects of this type of laser radiation. Study Design/Materials and Methods: Human osteoblast-like MG-63 cells were exposed to 3, 7, or 10 superpulsed laser irradiation (pulse width 200 nanoseconds, minimum peak power 45 W, frequency 30 kHz, total energy 60 J, exposure time 5 minutes). The following parameters were evaluated: cell growth and viability (light microscopy, lactate dehydrogenase release), calcium deposits (Alizarin Red S staining), expression of bone morphogenetic factors (real-time PCR). Results: Superpulsed laser irradiation decreases cell growth, induces expression of TGF-b2, BMP-4, and BMP-7, type I collagen, ALP, and osteocalcin, and increases the size and the number of calcium deposits. The stimulatory effect is maximum on day 10, that is, after seven applications. Conclusions: Reported results show that superpulsed laser irradiation, like the continuous and pulsed counterparts, possesses osteogenic properties, inducing the expression of molecules known to be important mediators of bone formation and, as a consequence, increasing calcium deposits in human MG-63 cells. Moreover, the data suggest a new potential role for PPARg as a regulator of osteoblast proliferation.

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“…In turn, the laser-induced transient heating could increase ROS production and lipid peroxidation [33].…”

Section: Discussionmentioning

confidence: 99%

Superpulsed laser irradiation increases osteoblast activity via modulation of bone morphogenetic factors

et al. 2009

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“…6,14,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] This evidence implies cytochrome C oxidase absorption, over other possible elements of the electron transport chain. Eells's group, for example, has demonstrated that low-intensity red light (670 nm) can modulate the effects of molecules known to directly inhibit cytochrome C oxidase activity.…”

mentioning

confidence: 99%

Low-Intensity Light Therapy: Exploring the Role of Redox Mechanisms

Tafur

Mills

2008

Photomedicine and Laser Surgery

149

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Low-intensity light therapy (LILT) appears to be working through newly recognized photoacceptor systems. The mitochondrial electron transport chain has been shown to be photosensitive to red and near-infrared (NIR) light. Although the underlying mechanisms have not yet been clearly elucidated, mitochondrial photostimulation has been shown to increase ATP production and cause transient increases in reactive oxygen species (ROS). In some cells, this process appears to participate in reduction/oxidation (redox) signaling. Redox mechanisms are known to be involved in cellular homeostasis and proliferative control. In plants, photostimulation of the analogous photosynthetic electron transport chain leads to redox signaling known to be integral to cellular function. In gene therapy research, ultraviolet lasers are being used to photostimulate cells through a process that also appears to involve redox signaling. It seems that visible and near visible low-intensity light can be used to modulate cellular physiology in some nonphotosynthetic cells, acting through existing redox mechanisms of cellular physiology. In this manner, LILT may act to promote proliferation and/or cellular homeostasis. Understanding the role of redox state and signaling in LILT may be useful in guiding future therapies, particularly in conditions associated with pro-oxidant conditions. 323

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“…57 Let us cite two experimental graphs as an example, that have also other interesting features (Figures 4 and 5). 58,59 Similar effect is certainly not observed in photobiology (see Figure 1). The first graph (Figure 4) is interesting in that ED (0.1 J/ cm 2) for pulsed lasers is ten times less than for continuous lasers and also for IR spectrum (20 J/cm 2 ) in a similar experimental model (E. coli proliferation), 60 which indicates greater efficiency of pulsed mode.…”

Section: Mechanisms Of Biological (Therapeutic) Action Of Low-intensimentioning

confidence: 54%

Low-Level Laser Therapy in Russia: History, Science and Practice

Moskvin

2017

J Lasers Med Sci

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In Russia (formerly USSR) study of biomodulation action (BMA) mechanisms of lowintensity laser irradiation (LILI) began in 1964, immediately after the development of lasers. During the period from 1965 to 1972 several dozens of scientific conferences were held, hundreds of studies were published. Generally, secondary mechanisms and results of LILI effect on patients with various diseases were studied. This data was immediately implemented into practical medicine in the fields of oncology, surgery, dermatology and dentistry, and since 1974 low level laser therapy (LLLT) is included in the standard of state medical care. For 50 years no less than 1000 books were published (monographs, collections, methodical and clinical materials), thousands of researches were carried out. Primary mechanism and patterns of interaction of LILI with acceptors within cells can be represented in the following order: absorption of photon's energy -emergence of a local temperature gradient -release of Ca 2+ from intracellular stores -stimulating Ca 2+ -dependent processes. Understanding of this process allowed the explanation of all known secondary effects, optimized methods and extremely increased effectiveness of LLLT. Owing to the knowledge of BMA mechanisms of LILI, numerous associated and combined LLLT techniques were developed and are widely used nowadays: locally, on the projection of internal organs, laser acupuncture, reflexology, intracavitary, transdermal and intravenous laser blood illumination, magnetic-laser therapy, laser phoresis, laser-vacuum massage, biomodulation, etc. About 400 000 laser therapeutic devices are used in Russian practical healthcare. Unique, having no analogues in the world devices, are produced -red pulsed laser diodes (wavelength 635 nm, power 5-40 W, pulse duration 100 ns, frequency 10 000 Hz) are designed specially for effective laser therapy.

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Two different mechanisms of low-intensity laser photobiological effects on Escherichia coli

Cited by 68 publications

References 9 publications

Superpulsed laser irradiation increases osteoblast activity via modulation of bone morphogenetic factors

Superpulsed laser irradiation increases osteoblast activity via modulation of bone morphogenetic factors

Low-Intensity Light Therapy: Exploring the Role of Redox Mechanisms

Low-Level Laser Therapy in Russia: History, Science and Practice

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