|
|
The Effect of Low-power Laser on the
Murine Hair Growth
Phil Sang Chung, M.D.1, You Chan Kim, M.D.1,2,
Min Sang Chung, B.S.1, Sang Oun Jung, PhD1, Chung Ku Ree, M.D.1
Medical Laser Research Center1,
Department of Dermatology2, Dankook University,
College of Medicine, Cheonan, Korea
ABSTRACT
1. The mouse irradiated by the Leimo showed 30% increase in the hair
growing speed.
2. The region irradiated by the Leimo shows the hair growing speed and the
density much higher than the region not irradiated by the LEIMO
3. As a result of the observation of tissue sample for the cause analysis,
it was found that the hair follicles was newly formed in the dermis
irradiated by the LEIMO
INTRODUCTION
The low-powered laser therapy is a therapeutic method to stimulate
voluntary healing on the damaged somatic part by photobiomodulation using
laser irradiation. Since the development of therapeutic laser systems for
medical and cosmetic purposes in 1960s, the somatic effect of low-powered
laser irradiation on pain relief and wound healing has been proved. In
addition, the low-powered laser has effects of anti-inflammation,
immunosuppression, vasodilatation, stimulated blood circulation and anti
edema, which are collectively called biostimulation effect [1,2.]
Biostimulative effect of low-powered laser is widely used in the various
medical fields because of convenience of use, easy to approach, stability
and non-invasiveness [1,2.] . Though the application of laser is expected
to affect hair growth by biostimulation such as vasodilatation and
stimulation of blood circulation, any literature relative to this effect
is hard to get [3,4]. Therefore, this study intended to evidence the
effect of low-powered laser treatment on hair growth of a mouse.
TEST SUBJECT AND METHOD
1. Subject animal
The test used 16 six-week C57BL/6 black mice bought from Samtako. The
subjects were used after they were stabilized for three days in the mouse
farm.
2. Laser source and procedure
(i) Laser source: This study employed the diode laser system (Model
name : LEIMO by Pros International Co.) with wavelength of 890nm and
frequency of 1500 Hz. Its power was about 1.5mW. Acryl module was
manufactured to apply laser (Fig. 1). The laser power was measured with
High-Performance Optical Meters (Model 2835-C, Newport, USA) by distance
between the laser and the detector.
[ Fig. 1 : Laser/LED Module ]
(ii) Test procedure
The hair on the back of a subject mouse was removed with an electric razor
and its remaining hair was completely eliminated by applying a hair
remover cream. Those subjects were divided into four groups; the first was
case-control group, the second group included mice applied by low-powered
laser, the third group was those who were applied with a hair stimulant
毛&More®, of LG Household & Health Care, and the last group
was applied with Spella 707®. Each group had four mice. For the second
group, the mice were fixed on the mouse holder and applied with laser for
20 minutes once a day (Fig. 2). The third and last groups were applied
with 毛&More®, and Spella 707®, respectively, once a day for
30 days. The status of hair growth was observed with time. The photos were
taken one day, seven days, nine days, fifteen days, and twenty-five days,
respectively, after the start of the test. To compare hair growth in the
laser-applied part and non-applied part, biopsy was performed 12 days
after the application of laser and the dyed part was observed with a light
microscope after hematoxylin-eosin dyeing.
[ Fig. 2 : Features of irradiating of LEIMO ]
RESULTS
The calculation of laser output power and treatment quantity by time
Output power of laser systems in the market was measured. The power was
observed at points from 0.5 cm apart from the detector at the interval of
1 cm, to a distance where laser was not detected. As a result of measuring
the power of laser with the detector, it was hardly detected at a point
over 8 cm apart from the laser and was at 1.5mW/cm2 at a point 1cm apart
(Table 1). As the most effective treatment time was 20 minutes as shown in
a preliminary test, the treatment time was fixed at 20 minutes and the
laser system was set 1 cm apart from the tissue. The laser was irradiated
at 1.8J per unit area (1.5mW/cm2 x 20 x 60sec = 1800mJ/cm2 = 1.8 J/cm2).
1 The power and power density of low-power laser according to the
distance between laser and detector.
|
Distance(cm)
|
Power(mW)
|
Power density(mW/cm2)
|
|
0.5
|
5.17 ¡¾ 0.15
|
1.64
|
|
1
|
4.68 ¡¾ 0.13
|
1.49
|
|
2
|
3.47 ¡¾ 0.16
|
0.31
|
|
3
|
2.46 ¡¾ 0.13
|
0.78
|
|
4
|
1.68 ¡¾ 0.13
|
0.52
|
|
5
|
1.19 ¡¾ 0.13
|
0.37
|
|
6
|
0.69 ¡¾ 0.08
|
0.21
|
|
7
|
0.35 ¡¾ 0.08
|
0.11
|
|
8
|
0.23 ¡¾ 0.17
|
0.07
|
2. Observation with naked eyes
For the case control group, the hair on the back of a
mouse started to grow on the 13th day after it was removed and returned to
a normal level 25 days later (Fig.3A).
[ Fig.3A : Control Group ]
For the second and third groups, the hair began to grow 9
days later and returned to a level prior to hair removal 20 days later
(Fig.3B, 3C). For the last group with Spella 707®, the mice experienced
their hair to start to grow on their backs 9 days later and recovered all
their hair 15 days later (Figure 3D).
[ Fig.3B : Laser Irradiation Group ]
[ Fig.3C : 毛&More®, Applied Group ]
[ Fig. 3D : Spella 707® Applied Group ]
The third group with laser treatment showed a difference
from the case control group and the groups treated with hair stimulants.
It was found that for the case control group and those applied with hair
stimulants, hair grew randomly on the hair-shaved area of a mouse as a
certain period of time passed (Figure 4A).
[ Fig. 4A : The pattern of hair growth after depilation:
Control Group ]
However, for the second group with laser irradiation, hair
started to grow on the laser-applied area and gradually expanded to
neighboring areas (Figure 4B).
[ Fig. 4B : The pattern of hair growth after depilation
: laser irradiated mouse ]
3. Histological Observation
12 days after laser treatment, many anagen hair follicles on the
laser-treated area were found while there were few hair follicles on the
non-treated area. (Fig 5, 6)
[ Fig.5 ]
Small and black-colored spot (hair follicles) is confirmed to exist in a
high density in the dermis.
[ Fig. 6 : Comparative result in the same population ]
The tissue irradiated by the laser formed the black-colored spot (hair
follicles) in a faster period of time than the tissues not irradiated by
the laser, and formed many new hair follicles in the dermis.
CONSIDERATIONS
High-powered laser mainly used for medical treatment causes tissues to
break after it is absorbed into a body and turned into thermal energy.
However, low-powered laser generates only a small amount of energy, of
which a direct irradiation induces somatic temperature change. The
temperature change induced by low-powered laser is confined in the range
from less than 0.10C to 0.50C [1,5]. While high-powered laser is an
expensive system that can raise output power up to 100 W, low-powered
laser is relatively a low-priced system that only has a few mW [5]. The
laser with 5mW was used in this test. Biological effects of low-powered
laser are widely reported including anti-inflammation, pain reduction,
wound healing, anti edema, antibiosis, immunity and local blood
circulation improvement [1,2,6-11].
These effects are called 'biostimulation' because they are
induced by stimulation. However, as low-powered laser is found to have a
suppressive effect as well as a stimulative effect, the terms such as low
intensity, low level or low power that focus on non-thermal, small energy,
are used instead of biostimulation [2]. The study and clinical application
of low-powered laser started in Eastern Europe in mid 1960s and now
low-powered laser is used worldwide to treat musculoskeletal disorders (MSD),
pain, inflammation and so on.
In England, more than 40% of physical therapy clinics use
low-powered laser and about 30% of dental clinics in Scandinavia use it.
But, it is seldom used in the US and is not approved by the US FDA [2].
Low-powered laser is used in various clinical areas for the therapeutic
purposes. Recently, it is reported that low-powered laser is efficacious
against rheumatoid arthritis, wound, post-sore neuralgia, damaged nerves,
recurring cold sores, and vitiligo[12-14].
In Korea, Kong and others [15] reported the laser
irradiation relieved post-sore neuralgia from 60% of patients who had
post-sore neuralgia. Kim and others [16] reported that the irradiation
relieved only pain for the laser-treated group of patients with herpes
zoster while it made no difference in skin rash from the case control
group.
In 2002, Vlacohs and others [3] reported for the first
time on two cases of terminal hair growing on a treated area as a side
effect after nevus flammeus and tattoo elimination using intense pulse
light that generates 400nm-1200nm. This phenomenon was presumed to take
place due to local inflammatory response because inflammation was very
severe on the laser-treated area for a few days. This side effect gives a
possibility of laser therapy for hair growth.
In fact, Satino and others [4] performed the test on 35
patients with androgen alopecia (28 men and 7 women) in 2003. The patients
were made to comb their hair every other day for six months, for five to
ten minutes with the brush that emitted low-powered laser beam. As a
result, the patients, men and women alike, showed a remarkable increase of
hair follicles and tensile strength on the temporal region and vertex.
These researchers assumed that even though they didn't
know how low-powered laser increased hair follicles and tensile strength,
one or more factors among improved micro-vascular circulation, reduced
inflammation and increased cell energy in the form of ATP (adenosine
triphosphatase) worked together. In this study, low-powered laser
irradiation stimulated hair growth. It was thought that laser irradiation
induced vasodilatation, which in turn, increased blood flow and improved
micro-vascular circulation that led to increased supply of nutrients. In
this study, the laser irradiation showed weaker effects or the same
effects with other hair growth stimulants on hair growth of the mice, but
it showed better effects compared with the case control group.
The fact that hair started to grow on the laser-irradiated
area indicated any relevance between low powered laser irradiation and
stimulation of hair growth and suggested the possibility of laser to be
used to treat hair loss. Further researches need to find the effect of
low-powered laser treatment on human hair growth and how the laser
stimulates hair growth.
REFERENCES
1. Babapour R, Glassberg E, Lask GP. Low-energy laser systems. Clin
Dermatol 1995;13:87-90
2. Basford JR. Low intensity laser therapy: still not an established
clinical tool. Lasers Surg Med 1995;16:331-342
3. Vlachos SP, Kontoes PP. Development of terminal hair following skin
lesion treatments with an intense pulsed light source.
Aesth Plast Surg 2002;26:303-307
4. Satino JL, Markou M. Hair regrowth and increased hair tensile strength
using the HairMax LaserComb for low-level laser therapy. Int J Cosm Aesth
Dermatol 2003;5:113-117
5. Yu HS, Wu CS, Yu CL, Kao YH, Chiou MH. Helium-Neon laser irradiation
stimulates migration and proliferation in melanocytes and induces
repigmentation in segmental vitiligo. J Invest Dermatol 2003:120:56-64
6. Mester E, Spiry T, Szende B, Tota JG. Effect of laser rays on wound
healing. Am J Surg 1971;122:532-535
7. Kana JS, Hutschenreiter G, Haina D, Waidelich W. Effect of low-power
density laser radiation on healing of open skin wounds in rats. Arch Surg
1981;116:293-296
8. Mester E, Mester AF, Mester A. The biomedical effects of laser
application. Lasers Surg Med 1985;5:31-39
9. Nemeth AJ. Lasers and wound healing. Dermatol Clin 1993;11:783-789
10. Tadakuma T. Possible application of the laser in immunobiology. Keio J
Med 1993;42:180-182
11. Conlan MJ, Rapley JW, Cobb CM. Biostimulation of wound healing by
low-energy laser irradiation. A review.
J Clin Periodontol 1996;23:492-496
12. Schindl A, Neumann R. Low-intensity laser therapy in an effective
treatment for recurrent herpes simplex infection. Results from a
randomized double-blind placebo-controlled study. J Invest Dermatol
1999;113:221-223
13. Khuller SM, Bordin P, Barkvoll P, Haanaes HR. Preliminary study of
low-level laser for treatment of longstanding sensory alteration in the
inferior alveolar nerve. J Oral Maxillofac Surg 1996;54:2-7
14. Goldman JA, Chiapella J, Casey H, Bass N, Graham J, McClatchey W, et
al. Laser therapy of rheumatoid arthritis. Lasers Surg Med 1980;1:93-101
|
|
Download
Report (pdf 371kb) Journal of the Korean Society Plastic
& Reconstructive Surgeons 2004
