Laser Therapy,
by Mary Dyson PHD FCSP continued page
3 For sale outside of
the United States only!
The
Beurer SoftLaser TM
This hand-held LLLT device is a low level Class 3A laser manufactured
in Germany by Beurer GmbH. It has a single probe containing a 5 mW
GaAlAs diode producing red light of 635-670 nm wavelength. It is powered
by 2 AAA batteries.
Application
of SoftLaserTM to skin
The probe is placed in contact with clean skin at right angles to
the skin’s surface and moved slowly over the region to be treated
for a few minutes, typically 3-6 minutes for a region of about 1 cm
diameter. A convenient way to use it is twice daily, shortly after
cleansing the skin in the morning and evening, and before the application
of a moisturizing cream and/or cosmetics.
LLLT
EFFECTS ON DAMAGED SKIN
Effects of
the Beurer SoftLaserTM on skin
The Beurer SoftLaserTM has been found by its users to:
Reduce wrinkles
Make scars less visible
Tighten large pores
Elevate pock marks
Improve skin tone
Give a temporary radiance to the skin
Soften chapped lips.
Treatment
of damaged skin with red light accelerates the resolution of inflammation,
leading to faster repair (Dyson 2004). The stimulated secretion of
collagen by fibroblasts at the site of a wrinkle or of a pock mark
will increase the thickness of the dermis locally, helping to fill
in the tissue deficit. The gradual removal of excessive scar tissue
may be due to the activation of fibroblasts, fibrocytes and other
cells in and around the scar.
As with any other technique, tissue repair can only be stimulated
by LLLT if it is absent or delayed. In these circumstances, epithelialisation
and granulation tissue production can be stimulated by LLLT as can
wound contraction (Dyson & Young 1986) This reduces the area in
which scar tissue is produced resulting in less obvious scarring.
HOW LLLT PRODUCES ITS EFFECTS
For LLLT to
be effective, the tissue targeted must absorb photons. Absorption
is wavelength dependent. Red light is absorbed by cytochromes in the
mitochondria; all human cells, other than mature red blood cells (erythrocytes)
contain mitochondria. Provided that appropriate wavelengths and energy
densities are used, cell activity can be stimulated if it is suboptimal.
Cells in which this has been investigated include mammalian keratinocytes,
lymphocytes, macrophages, mast cells, fibroblasts and endothelial
cells, all cells of significance in tissue repair. Much of the research
on this has been reviewed by Baxter (1994) and by Tuner and Hode (2002).
Cells affected by LLLT show a temporary increase in permeability of
their cell membranes to calcium ions (Young et al 1990). This may
be an important component of the mechanism by which LLLT modulates
cell activity; other electrotherapeutic modalities, such as ultrasound,
may act in a similar fashion (Dyson 2004).
The triggering of cell activity by reversible changes in membrane
permeability when photons are absorbed could be responsible for the
stimulation of tissue repair (Young & Dyson 1993). Increase in
calcium uptake by macrophages exposed to red light and IR in vitro
has been shown to be wavelength and energy density dependent. Of the
wavelengths tested, 660, 820 and 870 nm were effective; 880 nm was
ineffective. These same wavelengths also affected growth factor production
by the macrophages, 660, 820 and 870 nm being stimulatory, whereas
880 nm was not. Energy densities of 4 and 8 J/cm2 were found to be
effective; 2 and 19 J/cm2 were not (Young et al 1990). Red light of
660 nm wavelength is absorbed by the cytochromes of mitochondria,
where it stimulates ATP production and increases cytoplasmic H+ concentration,
which can affect cell membrane permeability (Karu 1988). IR radiation
of 820 and 870 nm may be absorbed by components of the cell membrane.
Some of these components vary in different cell types, which may be
why the IR wavelengths absorbed by cells differ according to the cell
type. For example, 870 nm affects macrophages (Young et al 1990) but
not mast cells (El Sayed & Dyson 1990). It may be possible to
selectively stimulate macrophages but not mast cells in vivo by exposure
to an 870 nm probe.
Following a reversible change in membrane permeability to calcium
ions, the cells respond by doing what they are programmed to do. In
the case of macrophages, this is to produce growth factors and to
phagocytose debris, whereas fibroblasts manufacture collagen and other
extracellular components of the dermis.
The molecular mechanisms by which LLLT affects cell activity begin
with photoreception, when the photons are absorbed. This is followed
by signal transduction, amplification and a photoresponse, e.g. cell
proliferation, protein synthesis and growth factor production, all
of which may assist in tissue repair. Membrane structure differs according
to the cell type, which, if IR is absorbed by parts of the membrane,
may explain why different cell types absorb different wavelengths
of IR. Theoretically, it should be possible by the judicious selection
of IR wavelengths to affect some cell types while leaving others unaffected.
In contrast red light, since it is absorbed by the mitochondrial cytochromes
present in all mammalian cells other than erythrocytes, and also by
the hemoglobin contained in erythrocytes, affects all mammalian cells.
Laser
therapy continued>> Page 4
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