Laser Stimulation on Bone Defect Healing: An In Vitro Study

Abstract

The aim of this in vitro study was to evaluate whether low-power laser (LPL) stimulation can accelerate bone healing. Bone defects of a standard area were created in the distal epiphysis of 12 femora explanted from six rats, and they were cultured in BGJb medium for 21 days. Six defects were treated daily with Ga-Al-As, 780 nm LPL for 10 consecutive days (lased group, LG), while the remainder were sham-treated (control group, CG). Alkaline phosphatase/total protein (ALP/TP), calcium (Ca), and nitric oxide (NO) were tested on days 7, 14 and 21 to monitor the metabolism of cultured bone. The percentage of healing of the defect area was determined by histomorphometric analysis. After 21 days significant increases were observed in ALP/TP in LG versus CG (p<0.001), in NO in the LG versus CG ( p<0.0005) and in Ca in CG versus LG ( p<0.001). The healing rate of the defect area in the LG was higher than in the CG ( p=0.007). These in vitro results suggest that Ga-Al-As LPL treatment may play a positive role in bone defect healing.

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

“…3 Newly formed bone in the defects of the treatment groups presented as mean percentages and standard errors (groups connected by bars are not significantly different) seeking to show that this kind of treatment could be feasible and could be standardized in a new faster easily applied protocol. In the present study, when the laser was applied alone, the presence of organizing connective tissue, with blood capillaries and fibroblasts was observed, a result similar to those of others [17,[24][25][26]. Small amounts of trabecular bone were also observed, as found by Gerbi et al [21], indicating acceleration of the tissue repair process, as reported by Ozawa et al [2], who found an increase in cell proliferation and differentiation after laser irradiation.…”

“…Histomorphometric analysis revealed that defects of group 3 (laser and pure rhBMP-2) showed the greatest area of bone formation. The use LLLI for different treatments and indications, such as pain control and tissue recovery, including mineralized tissues, has been reported [17,18]. BMPs, especially the BMP-2, have osteoinductive properties, causing mesenchymal cells to differentiate into osteoblastic cells [19,20].…”

O efeito do laser de baixa energia no crescimento bacteriano "in vitro"

“…Suas possíveis aplicações clínicas, como modalidade terapêutica, em lesões de partes moles e de tecido ósseo, têm sido largamente estudadas. Conquanto não exista consenso com relação aos efeitos biológi-cos do LBE no processo de reparo ósseo, seu uso parece promissor no manejo adjuvante de lesões de tecidos moles, associadas ou não à fratura (1)(2)(3)(4)(5)(6)(7)(16)(17) . Seu efeito bioestimulante, que ocorre localmente, por aumento do metabolismo celular e por redução da resposta inflamatória, está diretamente associado ao estímulo da função mitocondrial e das células do sistema fagocítico mononuclear (3,6) .…”

Biological Function of Low Reactive Level Laser Therapy (LLLT)

“…Although the specific mechanism remains unknown, laser-induced intracellular generation of reactive oxygen species probably involves energy transfer from PPIX and other photoacceptors present in the cell. In addition, several groups have described cellular functions mediated by nitric oxide (NO), which is upregulated by laser irradiation, as well as by inducible nitric oxide synthase (iNOS) [79,[81][82][83][84]. The mechanism of laser-induced control of cellular functions is believed to hinge on the regulation of photoacceptor activity and the intracellular levels of reactive oxygen species.…”