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

Abstract

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.

Effects of the combination of low-level laser irradiation and recombinant human bone morphogenetic protein-2 in bone repair

“…The laser irradiation used in this study was in continuous emission mode, but in an in vitro study, it was observed that superpulsed laser irradiation has osteogenic properties, inducing the expression of molecules known to be important mediators of bone formation and, as a consequence, increasing calcium deposition in human cells [23]. Fig.…”

Superpulsed laser therapy on healing process after tooth extraction in patients waiting for liver transplantation

“…It has been demonstrated that laser therapy stimulates cell proliferation and the formation of lymphatic and blood vessels [31,32], and it may improve bone mineralization [10,33,34]. The effect of laser therapy on bone regeneration has been the focus of recent researches, including in dentistry.…”

“…Studies have investigated the ability of this irradiation to stimulate both bone production and boneimplant interaction [10,35].…”

“…In general, low-level laser therapy (LLLT) has been used for several years, and no adverse effects have been demonstrated [5,7]. It is thought to reduce pain [8,9], accelerate wound healing and reduce the inflammatory process, it also enhances bone remodelling and repair [5,10]. A literature review of studies regarding wound healing in general identified 47 relevant studies in rodents.…”

A renaissance in low-level laser (light) therapy – LLLT

“…Many applications of LLLT may require deep penetration of the light energy, such as: lower back, neck, and hip joint pain and inflammation. Therefore, if the power densities needs to be greater than a few mW/cm 2 and is to be delivered safely to target tissues > 5 cm below the skin surface, the effective treatment can only be achieved by using superpulsed lasers [19] . The data indicate that pulsing and particularly superpulsing is playing an important role in LLLT especially for clinical applications where deep tissue penetration is required.…”