Initial effects of low-level laser therapy on growth and differentiation of human osteoblast-like cells

Abstract

Low-level laser therapy is a clinically well established tool for enhancement of wound healing. In vitro studies have also shown that low level laser therapy has a biostimulatory effect on cells of different origin. The aim of this in vitro study was to investigate the initial effect of low-level laser therapy on growth and differentiation of human osteoblast-like cells. SaOS-2 cells were irradiated with laser doses of 1 J/cm2 and 2 J/cm2 using a diode laser with 670 nm wave length and an output power of 400 mW. Untreated cells were used as controls. At 24 h, 48 h and 72 h post irradiation, cells were collected and assayed for viability of attached cells and alkaline phosphatase specific activity. In addition, mRNA expression levels of osteopontin and collagen type I were assessed using semi-quantitative RT-PCR. Over the observation period, cell viability, alkaline phosphatase activity and the expression of osteopontin and collagen type I mRNA were slightly enhanced in cells irradiated with 1 J/cm2 compared with untreated control cells. Increasing the laser dose to 2 J/cm2 reduced cell viability during the first 48 h and resulted in persistently lower alkaline phosphatase activity compared with the other two groups. The expression of osteopontin and collagen type I mRNA slightly decreased with time in untreated controls and cells irradiated with 1 J/cm2, but their expression was increased by treatment with 2 J/cm2 after 72 h. These results indicate that low-level laser therapy has a biostimulatory effect on human osteoblast-like cells during the first 72 h after irradiation. Further studies are needed to determine the potential of low-level laser therapy as new treatment concept in bone regeneration.

Low‐level laser irradiation enhances BMP‐induced osteoblast differentiation by stimulating the BMP/Smad signaling pathway

“…In osteoblast-like cells isolated from fetal rat calvariae, LLLI stimulated proliferation and differentiation, inducing expression of alkaline phosphatase (ALP), osteopontin (OP), and bone sialoprotein [Ueda and Shimizu, 2003]. Similar results were obtained in cultured human SaOS-2 cells, where early induction of ALP, type I collagen (ColI), and OP was observed in cells irradiated with a 670 nm diode laser [Stein et al, 2005[Stein et al, , 2008. Moreover, LLLI treatment of human osteoblast-like cells cultured on titanium induced both proliferation and differentiation in a dosedependent manner through increased osteocalcin and transforming growth factor (TGF)-b1 production [Khadra et al, 2005].…”

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

“…In osteoblast-like cells isolated from fetal rat calvariae, LLLT stimulated proliferation and differentiation, inducing alkaline phosphatase (ALP), osteopontin (OP), and bone sialoprotein expression [8]. Similar results have been obtained in cultured human SaOS-2 cells, where early induction of ALP, type I collagen, and OP was observed in cells irradiated with 670 nm diode laser [9,10]. Moreover, treatment with LLLT of human osteoblast-like cells, cultured on titanium, induced cellular activity in a dose-dependent manner, through increased osteocalcin and TGF-b 1 production [11].…”

Ação da laserterapia no processo de proliferação e diferenciação celular: revisão da literatura

“…Numerosos estudos experimentais in vitro já foram realizados 7,10,12,13,31,26,27,28 concordando com a hipótese de que a laserterapia seja capaz de influenciar os processos metabólicos celulares, ao aumentar a proliferação de várias células, como os fibroblastos, osteoblastos, queratinócitos, células tronco e células oriundas de tumores malignos.…”