The effects of combined low level laser therapy and mesenchymal stem cells on bone regeneration in rabbit calvarial defects

Abstract: This study evaluated the effect of Low Level Laser Therapy (LLLT) and Mesenchymal Stem Cells (MSCs) on bone regeneration. Background data: Although several studies evaluated the effects of MSCs and LLLT, there is little information available regarding in vivo application of LLLT in conjunction with MSCs. Methods: Forty-eight circular bone defects (6 mm in diameter) were prepared in the calvaria of 12 New- Zealand white rabbits. The defects of each animal were randomly assigned to 4 groups: (C) no treatment; (L) applying LLLT; (SC) filled with MSCs; (SCL) application of both MSCs and LLLT. LLL was applied on alternate days at wavelength of 810 nm, power density of 0.2 W/cm2 and a fluency of 4 J/cm2 using a Gallium–Aluminum–Arsenide (GaAlAs) diode laser. The animals were sacrificed after 3 weeks and then histological samples were evaluated to determine the amount of new bone formation and the remaining scaffold and inflammation. Results: The histological evaluation showed a statistically significant increase in new bone formation of LLLT group relative to the control and the other two experimental groups (p < 0.05). There was no significant difference in bone formation of the control group compared to experimental groups filled with MSCs. Laser irradiation had no significant effect on resorption of the scaffold material. In addition, inflammation was significantly reduced in LLLT group compared to the control defects and the other two experimental groups. Conclusion: Low level laser therapy could be effective in bone regeneration but there is no evidence of a synergistic effect when applied in conjunction with MSCs

Comment on: An engineering thermodynamic approach to select the electromagnetic wave effective on cell growth

[No abstract available

Effects of Photobiomodulation and Mesenchymal Stem Cells on Articular Cartilage Defects in a Rabbit Model

Objective: The aim of this study was to evaluate the effectiveness of the application of cultured autologous bone marrow mesenchymal stem cells (BMSCs) with scaffold and low-level laser therapy (LLLT) on the repair of articular cartilage defects in rabbits. Background data: For healing of the articular cartilage defects, although positive effects of BMSCs and LLLT have been demonstrated, their combination effect is still unknown; therefore, we investigated combining these two techniques has a synergistic effect. Materials and methods: After bone marrow aspiration from 10 rabbits, BMSCs were isolated, cultured in monolayer, suspended on a type I collagen scaffold and then implanted onto a full-thickness osteochondral defect (4 mm in diameter), artificially made on the patellar groove of both knees in the same rabbits. Then a knee was selected randomly in each rabbit as the experimental group, and subjected to Ga-Al-As (810 nm) laser irradiation with energy density of 4 J/cm2 every other day for 3 weeks. As the control group, the other knee did not receive LLLT. After this period, animals were euthanized and osteochondral defects were evaluated by histomorphometric methods. Results: No significant difference in new cartilage formation and inflammation was found between the groups (p > 0.05). However, there was significantly more new bone formation in the experimental group (p < 0.05). Conclusions: In terms of our research, although better healing in osteochondral defects was seen when combining BMSCs and LLLT compared with the use of BMSCs alone, this improvement was predominantly caused by new bone formation rather than new cartilage formation. © 2016, Mary Ann Liebert, Inc