Laser-Accelerated Inflammation/Pain Reduction and Healing
Please note: These pages represent only a tiny sample of the
resarch available on Low Level Laser, and are purely for general
information purposes, to give you
an idea of the scope of Low Level laser, how it works, what Low Level Laser research
studies show about its
general effects, and
the wide range of health
issues that have been helped by it. The thousands of published studies on Low Level Laser have used
various systems from various manufacturers, or more basic or specialised systems built in
research centres,
so strictly speaking, similar results can not be extrapolated to systems other than those
used in the studies. Health and wellness are also very individual issues, so these
studies should not be
interpreted as proof that anyone other than the study participants would receive the same
reported benefits. This
section is provided purely as a source of inspiration in how Low Level laser might help you
improve your own health. We do not treat or diagnose conditions -- our approach is that if
your body has the optimal conditions for good health, it will be better equipped to deal with any
health challenges it may face, now or in the future.
Low Level Laser Therapy (LLLT) precipitates a complex set of physiologial interations at the
cellular level that redues acute inflammation, reduces pain, and accelerates tissue healing
Richard Martin, BS, CLT
Compromised cells and tissues respond more readily than healthy cells or tissues to energy
transfers that occur between LLLT-emitted photons and the receptive chromophores found in the
various cells and sub-cellular organelles. Cells and tissues that are ischemic and poorly perfused
as a result of inflammation, edema and injury have been shown to have a significantly higher
response to irradiation than normal healthy strutures. Cell membranes, mitochondria and damaged
neurological structures exhibit less than optimal metaolism and stasis conditions. Multiple studies
have demonstrated that under these compromised conditions, the introdution of energy transfers and
the resultant enhancement of metabolic activity is most pronouned in biologically challenged
components. While it may appear that is thus selectively targeting compromised cells, in reality,
these cells exhibit a lowered reaction threshold to the effets of laser light and are more easily
triggered to energy transfer responses. The result is that has a significant effect on damaged
cells and tissues while normative biological constituents are appreciably less affected
The cellular casade effect precipitated the actions of enzymes and having a significant in the
presence of has a significant impact on cellular and tissue function. Since a considerable number
of the reactive proteins that respond to laser stimulation are enzymes, laser light effects are
amplified in the stimulation of beneficial enezymes and depression of deleterious enzymes.
At the cellular level, cytochromes can be defined as electron or proton-transfer proteins that
act as energy producers for human biological functions. Both of the cytochrome enzymes, Cytochrome
Oxydase and Nitrix Oxide Synthase (NOS) have been found to be particularly reactive to laser photon
stimulation. The particular affinity of these and other photoreactive enzymes to accelerate their
funtions in the presence of provides critical increases in the molecule and Nitrix Oxide (NO) which
enhances cellular metabolism, circulatory improvement and nerve funtion.
Although the various actions of in regards to inflammation, pain and healing have been separated
categorically here for the purpose of process identification, their interactions are not so easily
distinguished. In response to LLLT, the reduction in inflammation, pain and healing time all
compliment each other and many of the processes are either simultaneous or overlapping.
Acute Inflammation Reduction
Immediately after an acute injury event, the body, in response to the disruption of the
integrity of vasular, soft tissue, connective tissue and neurological processes, initiates a series
of biologial responses. The inflammatory reaction consists of both vasuclar and cellular events.
Injury responsive components such as Mast cells, Bradykinins and Prostaglandins are activated along
with the vascular responses and cellular membrane reactions. All of these combined processes and
events are represented the symptoms of edema, inflammation, pain and functional debility LLLT can
be effective in mediating both the symptoms and the underlying inflammatory process the following
actions.
1. Stabilization of cellular membrane . Ca++, Na+ and concentrations as well as the proton
gradient over the mitochondria membrane are positively influenced. This is accomplished in part the
prodution of beneficial Reactive Oxygen Species (ROS) wherein triplet oxygen molecules absorb laser
light producing singlet oxygen molecules. These ROS modulate intracellular Ca++ concentrations and
laser therapy improves Ca++ uptake in the mitochondria. 2,3,4
2. ATP production and synthesis are significantly enhanced, contributing to cellular repair,
reproduction and functional ability. Laser stimulation of Cytochrome c Oxidase, a chromophore found
on the mitochondria of cells, plays a major role in this rapid
increase in production and synthesis of ATP. 3
3. Vasodilation is stimulated via Histamine, Nitric Oxide (NO) and Serotonin increases,
resulting in reduction of ischemia and improved perfusion. Laser mediated vasodilation enhances the
transport of nutrients and oxygen to the damaged cells and facilitates repair and removal of
cellular debris. 5, 6
4. Beneficial acceleration of leukocytic activity results in enhanced removal of non-viable
cellular and tissue components, allowing for a more rapid repair and regeneration process.
5. Increased Prostaglandin synthesis, particularly in conversion of the prostaglandins PGG2 and
PGH2 periossides into prostaglandin PGI2. PG|2 (Prostacyclin), has a vasodilating and
anti-inflammatory action with some attributes similar to Cox-I and Cox-II inhibitors.
7
6. Reduction in Interleukin 1(IL-1). Laser irradiation has a reducing effect on this
pro-inflammatory cytokine that has been implicated in the pathogenesis of rheumatoid arthritis and
other inflammatory conditions. 8
7. Enhanced lymphocyte response. In addition to increasing the number of lymphocytes, laser
irradiation mediates the action of both lymphatic helper T-cells and suppressor T-cells in the
inflammatory response. Along with laser modification of beta cell activity, the entire lymphatic
response is beneficially affected by LLLT. 9
8. Increased angiogenesis. Both blood capillaries and lymphatic capillaries have been clinically
documented to undergo significant increase and regeneration in the presence of laser irradiation.
The resulting improvement in circulation and perfusion enhances all repair and healing processes.
Laser induced increases in NO and the growth factors, in particular cytokine INF-g are contributory
to this process. 10, 11
9. Temperature modulation. Areas of inflammation typically demonstrate temperature variations
with the inflamed portion having an elevated temperature. Laser therapy has been shown to
accelerate temperature normalization, demonstrating its beneficial influence on the inflammatory
process.
10. Enhanced superoxide dismutase (SOD) levels. Laser stimulated increases in cytokine SOD
levels interact with other anti-inflammatory processes to accelerate the termination of the
inflammatory process. Interactions between SODand Reactive Oxygen Species (ROS) production
subsequent to LLLT balance free radical activity and allows for the beneficial effects of ROSwhiIe
inhibiting detrimental interactions. 12
11. Decreased C-reactive protein and neopterin levels. Laser therapy has been shown to lower the
serum levels of these inflammation markers, particularly in rheumatoid arthritis patients.
Decreased marker levels are indicative that the combined effects of all LLLT-induced
anti-inflammatory actions are effectively reducing the inflammatory process.
A summary flowchart of the cellular cascade in reducing tissue inflammation is presented in
Figure 1. The cumulative effect of these multiple inter-active processes and events is an
accelerated inflammatory cycle with diminished symptoms and earlier normalization.
Since LLLT does not exacerbate the inflammatory process but rather condenses the time frame from
onset to resolution through acceleration of processes, it can be used immediately post injury. This
rapid initiation of therapy in acute inflammation will assist in limiting the scope and duration of
the inflammatory event and minimize the pain and severity associated with it.
Most of the beneficial effects seen from LLLT in the treatment of acute inflammatory events will
also have medical efficacy as LLLT is initiated in more chronic Inflammatory conditions While the
treatment regimen and course of therapy may be modified in chronic situations, the physiological
responses and interactions remain consistent. Chronic conditions may require longer treatment times
and results will vary with the patient, condition and length of the chronic condition.
Pain Reduction
The unique pain reduction abilities of LLLT have been extensively researched and documented in
numerous clinical studies and medical papers. While there remains much to learn in respect to the
various processes through which LLLT achieves its pain reduction characteristics, there is a wealth
of knowledge currently available to demonstrate the effectiveness of laser therapy in this regard.
Because the pain amelioration capabilities of LLLT are accomplished via the combination of local
and systemic actions, utilizing enzymatic, chemical and physical interventions . the process is
very complex. However, there is a preponderance of medical evidence thatjustifies a conclusion that
effective pain reductions can be achieved via LLLT. Following are processes and events that are
promoted by LLLT therapy:
1. Increase in b-Endorphins. the localized and systemic increase of this endogenous peptide
after LLLT irradiation has been clinically reported in multiple studies with subsequent pain
reductions.
2. Blocked depolarization of C-fiber afferent nerves. The pain blocking effect of LLLT can be
pronounced, particularly in low velocity neural pathways, such as non-mylenated afferent axons from
nociceptors. Laser irradiation suppresses the excitation of these fibers in the afferent sensory
pathway. 13, 14
3. Increased nitric oxide production. NO has both a direct and indirect impact on pain
sensation. As a neurotransmitter it is essential for normal nerve cell action potential in impulse
transmission activity and, indirectly, the vasodilation effect of NO can enhance nerve cell
perfusion and oxygenation.
4. Increased nerve cell action potential. Healthy nerve cells tend to operate at about -70 mV
and fire at about -20 mV. Compromised cells membrane potential approximates -20 mV thereby
resulting in pain stimulus. LLLT can help restore the action potential closer to the normal -70 mV
range. Both compound muscle action potential (CMAP) values and nerve latency values have shown
improvement with laser therapy. 15
5. Axonal sprouting and nenxe cell regeneration. Several studies have documented the ability of
LLLT to induce axonal sprouting and some nerve regeneration in damaged nerve tissues. Where pain
sensation is being magnified due to nerve structure damage, cell regeneration and sprouting may
assist in pain decrease. 16, 17
6. Decreased Bradykinin levels. Since Bradykinins elicit pain by stimulating nociceptive
afferents in the skin and viscera, mitigation of elevated levels through LLLT can result in pain
reduction. Laser-induced decrease in plasma kallikrein, increase in Kininase II, and increase in NO
are considered the contributors to this Bradykinin decrease.
7. Increased release of acetylcholine. By increasing the available acetylcholine, LLLT helps in
normalizing nerve signal transmission in the autonomic, somatic and sensory neural pathways.
8. Ion channel normalization. LLLT promotes normalization in Ca++, NA+ and K+ concentrations
resulting in beneficial pain reduction results from these ion concentration shifts. Figure 2
presents a simplified representation of the effects of LLLT on pain improvement at the cellular
level.
Tissue Healing
One of the truly unique characteristics of LLLT is that it has the ability to actually promote and
enhance healing, not just treat symptoms. The irradiation by low-level laser light accelerates and
enhances healing activities carried out by the body. Several of the unique characteristics of LLLT
that work to alleviate pain and inflammation also play an important role in accelerating the
healing process; the LLLT-mediated reduction in inflammation and pain frees the body’s natural
ability to repair and heal itself. As wound healing progresses through the stages of inflammation,
proliferation, remodeling and maturation, laser therapy presents the opportunity to impact each of
these phases in positive and beneficial ways. LLLT can provide the following beneficial impacts in
both open surface wounds and closed connective or soft tissue injuries as follows:
1. Enhanced leukocyte infiltration. LLLT stimulates activity involving neutrophils, monocytes
and lymphocytes.
2. Increased macrophage activity. LLLT accelerates macrophage activity in phagocytosis, growth
factor secretion and stimulation of collagen synthesis.
3. Increased neovascularization. The significant angiogenesis that occurs with laser therapy
promotes revascularization with subsequent improvement in perfusion and oxygenation. Endothelial
cell regeneration is accelerated. 18
4. Increased fibroblast proliferation. LLLT stimulation increases fibroblast numbers and
fibroblast-mediated collagen production. 19
5. Keratinocyte proliferation. The beneficial synthesis activities and growth factor ability of
keratinocytes are enhanced by proliferation secondary to LLLT. 20
6. Early epithelialization. Laser-stimulated acceleration of epithelial cell regeneration speeds
up wound healing, minimizes scarring, and reduces infection opportunities.
7. Growth factor increases. Two to five fold increases in growth-phase-specific DNAsynthesis in
normal fibroblasts, muscle cells, osteoblasts and mucosal epithelial cells irradiated with IR light
are reported. Increases in vascular endothelial growth factor (VEGF) and fibroblast growth factor
(FGF-2) secondary to IR light irradiation have also been reported.
8. Enhanced cell proliferation and differentiation. Laser-induced increases in NO, ATPand other
compounds that stimulate higher activity in cell proliferation and differentiation into mature
cells. Increased numbers of myofibroblasts, myofibrils, myotubes etc., as well as bone cell
proliferation, have been clinically documented after LLLT. Satellite cells, the precursor cells in
the process of muscle regeneration, show significant increase in proliferation when irradiated with
LLLT. 21,22,23
9. Greater healed wound tensile strength. In both soft tissue and connective tissue injuries,
LLLT can increase the final tensile strength ofthe healed tissue. By increasing the amount of
collagen production/synthesis and by increasing the intra and inter-molecular hydrogen bonding in
the collagen molecules, laser therapy contributes to improved tensile strength.
24,25,26,27 The preceding effects combine to achieve an accelerated healing rate (see
Figure 3). The time from onset of injury to mature healed wound is reduced. 28
Conclusion
The FDA has recently cleared multiple laser and LED devices for treatment of a variety of medical
conditions including carpal tunnel syndrome, cervical neck pain, low back pain, joint pain,
generalized muscle pain and acceleration of wound healing. Governmental agencies such as NASA are
currently using technical light therapy for medical conditions in space applications. The U.S.
Olympic training facilities have just released statements of endorsement for laser therapy for
athletes. All of these events validate the growing acceptance in mainstream medicine for the
medical efficacy of laser therapy as a viable, often superior therapeutic treatment modality.
With over 200 clinical studies. many of which are double-blind, placebo-controlled, and in
excess of 2000 published articles on LLLT, this innovative new technology has a well-documented
research and application history. Having grown far beyond its distant Institutional Review Board
(IRB) and experimental treatment status, LLLT is now being considered a therapy of choice for many
difficult pain management challenges such as fibromyalgia and myofascial pain. New and ongoing
clinical investigations offer growing potential for even more widespread applications of this truly
unique light therapy.
Richard Martin, BS, CLT is a photobiologist specializing in laser therapy and holds the position
of Director of Science at Micro Light Laser, a subsidiary of Innovative Medical Group Corporation
in Santa Monica, CA. He has taught laser physics and photodynamics for eight years. He has sewed as
manager for several biomedical design and service facilities and participated as lead researcher
for biomedical devices involved in emergency cardiac care, warmed intravenous fluid therapy and
laser therapy. Richard has participated in medical clinical trials for 15 years as a clinical trial
analyst and contributing clinician.
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