Height Increase with Lasers?

Chondrogenic mRNA expression in prechondrogenic cells after blue laser irradiation.

"For chondrogenic induction, ATDC5 cells were irradiated with a blue laser (405 nm, continuous wave) at 100 mW/cm(2) for 180 s following incubation in chondrogenic differentiation medium. Differentiation after laser irradiation was quantitatively evaluated by the measurement of total collagen contents and chondrogenesis-related mRNAs. The total amount of collagen and mRNA levels of aggrecan, collagen type II, SOX-9, and DEC-1 were increased relative to those of a non-laser irradiated group after 14 days of laser irradiation. On the other hand, Ap-2alpha mRNA, a negative transcription factor of chondrogenesis, was dramatically decreased after laser irradiation.  Intracellular reactive oxygen species (ROS) were generated after laser irradiation."

"Msx1 and 2, retinoic acid receptor, Zfp60, and Ap-2α have been found to suppress or delay chondrocyte differentiation"

"Light is thought to be absorbed by mitochondrial respiratory chain components, resulting in the increase of ROS, and adenosine triphosphate (ATP)/or cyclic AMP, and initiating a signaling cascade which promotes cellular proliferation and cytoprotection"

The effects of low-level laser therapy, 670 nm, on epiphyseal growth in rats.

" the aim of this study was to evaluate the use of LLLT, 670 nm, at three different doses on the epiphyseal growth of the right tibia of rats. Twenty-one Wistar rats, aged four weeks, were subjected to the application of LLLT, with dosage according to the group (G4: were submitted to the application of 4 J/cm(2); G8: were submitted to the application of 8 J/cm(2); G16: were submitted to the application of 16 J/cm(2)). After completion of protocol they were kept until they were 14 weeks of age and then submitted to a radiological examination (evaluation of limb length) and euthanised. The histological analysis of the growth plates (total thickness and hypertrophic and proliferative zones) was then performed. Comparisons were made with the untreated left tibia. No differences were observed in any of the reviews (radiological and histological), when comparing the right sides (treated) to the left (untreated). It was concluded that the treatment with LLLT within the parameters used caused changes neither in areas of the epiphyseal cartilage nor in the final length of limbs."

"Both the thermal, and nonthermal effects of ultrasound can produce changes in epiphyseal growth. Nonthermal effects occur through the alteration of membrane permeability to calcium influx, modulating the nuclear proliferation and also the RNA transduce. These effects are also found in low level laser therapy"

"The effect produced by LLLT irradiation is due to the absorption of energy by specific photoreceptors, such as porphyrin and cytochrome c oxidase. This generates increased production of oxygen, which stimulates the activity of mitochondria in ATP production, increases chemiosmosis, the production of DNA and the influx of calcium into the cytoplasm, which leads to mitosis and cell proliferation. These effects cause increased cell proliferation and migration, increased tissue oxygenation, and the modulation of cytokine levels, growth factors, and inflammatory mediators. As a result of these reactions, the laser produces anti-inflammatory and analgesic effects, promotes healing, the formation of blood vessels, and the stimulation of fibroblasts and bone cells"

"With respect to radiographic analysis, the medical report showed: soft tissue unchanged; bone texture preserved; joint surfaces smooth, and regular and symmetrical epiphyseal nucleus with normal dimensions"

Effect of GaAlAs laser irradiation on the epiphyseal cartilage of rats.

"To study the effect of an 830-nm gallium-aluminum-arsenic (GaAlAs) diode laser at two different energy densities (5 and 15 J/cm(2)) on the epiphyseal cartilage of rats by evaluating bone length and the number of chondrocytes and thickness of each zone of the epiphyseal cartilage.

A total of 30 male Wistar rats with 23 days of age and weighing 90 g on average were randomly divided into 3 groups: control group (CG, no stimulation), G5 group (energy density, 5 J/cm(2)), and G15 group (energy density, 15 J/cm(2)). Laser treatment sessions were administered every other day for a total of 10 sessions. The animals were killed 24 h after the last treatment session. Histological slides of the epiphyseal cartilage were stained with hematoxylin-eosin (HE), photographed with a Zeiss photomicroscope, and subjected to histometric and histological analyses. Statistical analysis was performed using one-way analysis of variance followed by Tukey's post hoc test. All statistical tests were performed at a significance level of 0.05.

Histological analysis and x-ray radiographs revealed an increase in thickness of the epiphyseal cartilage and in the number of chondrocytes in the G5 and G15 groups.

The 830-nm GaAlAs diode laser, within the parameters used in this study, induced changes in the thickness of the epiphyseal cartilage and increased the number of chondrocytes, but this was not sufficient to induce changes in bone length{likely as chondrocyte hypertrophy is the predominant increaser of bone length}."

"the chondrocyte layers that form the epiphyseal cartilage revealed that the resting cells, which are located on the boundary between the epiphyseal growth plate and osseous epiphysis, had a small number of chondrocytes distributed in the extracellular matrix. The general aspect of the cells suggested a small mitotic activity; also, cells were surrounded by reduced lacunar spaces, which is indicative of reduced cell activity."

"a case of a child with tissue damage in two distal phalangeal epiphyseal plates associated with the use of a CO2 laser for wart removal that resulted in deformity and shortening of the digits, requiring corrective osteotomy."


Low-level laser on femoral growth plate in rats.

"Thirty male Wistar rats aged 40 days were divided into two groups, G1 and G2. In G1 the area of the distal growth plate of the right femur was irradiated at one point using GaAlAs laser 830 nm wavelength, output power of 40 mW, at an energy density of 10 J/cm(2). The irradiation was performed daily for a maximum of 21 days. The same procedure was done in G2, but the probe was turned off. Five animals in each group were euthanized on days 7, 14 and 21 and submitted to histomorphometric analysis.

In both groups the growth plate was radiographically visible at all moments from both craniocaudal and mediolateral views. On the 21st day percentage of femoral longitudinal length was higher in G2 than G1 compared to basal value while hypertrophic zone chondrocyte numbers were higher in G1 than G2. Calcified cartilage zone was greater in G1 than in G2 at all evaluation moments. Angiogenesis was higher in G1 than in G2 at 14th and 21st days.

The low-level laser therapy negatively influenced the distal femoral growth plate."

"the rats were approximately 6 weeks of age on the first day of irradiation, a transitional period between a phase of accelerating growth (up to 5 weeks) and a time of decelerating growth (8-16 weeks), indicating that irradiation action occurs despite the longitudinal length rate of the bone."

"elevated angiogenesis may have contributed to early chondrocyte death and formation of calcified cartilage, contributing to reduction of the femoral longitudinal length."

"In another study, irradiation of the rat mandible growth center (Α=904 nm, 2000 Hz, pulse length 200 ns and output power 4 mW) on days 0, 2, 4, 6, 8 and 10, with the protocol repeated after a 50-day interval, produced higher growth than that observed in controls"