Influence of low-level laser irradiation on osteocalcin protein and gene expression in bone tissue1

Abstract

To evaluate osteocalcin gene and protein expression in vitro and in an in vivo model of ostectomy. Methods: Twenty Wistar rats were assigned into two groups A (n=10, laser) and B (n=10, control). Ostectomy was performed in the femur diaphysis; the twenty fragments removed, composed in vitro groups named as in vivo (A and B) and cultivated in CO 2 atmosphere for thirteen days. Low-level laser irradiation was performed in groups A (in vivo and in vitro) by an GaAlAs device (λ=808 nm, dose of 2J/cm 2 , power of 200mW, power density of 0.2W/cm 2 , total energy of 1.25J, spot diameter of 0.02mm) for 5 seconds, at one point, daily. It was performed immunocytochemistry assays in vivo and in vitro groups. In vitro groups were also submitted to RNA extraction, cDNA synthesis and gene expression by quantitative PCR. Statistical analysis was realized with p<0.05. Results: Immunocytochemistry scores showed no significant differences between control and laser groups either in vivo and in vitro. Gene expression also showed no statistical differences. Conclusion: Low-level laser irradiation did not alter osteocalcin protein and gene expression in vivo and in vitro in the studied period but it may have been expressed them in an earlier period.

Laser therapy increases the proliferation of preosteoblastic MC3T3‐E1 cells cultured on poly(lactic acid) films

“…Furthermore, the flow cytometry cell cycle analysis demonstrated that the Laser + PLA group presented a higher percentage of cells in the proliferative cell cycle phases (S and G2/M), when compared with the Control and PLA groups. This lends support to previous literature findings reporting that photobiomodulation applied to bone cells can activate DNA, RNA, and cell cycle regulatory protein syntheses, increasing the speed of the mitotic cycle by intensifying DNA synthesis (Bomfim, Sella, Thomasini, & Plapler, 2018).…”

Evaluation of Aquaporins 1 and 5 Expression in Rat Parotid Glands After Volumetric Modulated Arc Radiotherapy and Use of Low-Level Laser Therapy at Different Times

“…Studies evaluating gene expression by qPCR after the use of LLLT have shown conflicting results regarding its effect. 29 These results may be related to the heterogeneity of sample composition, given that the samples included the entire anatomical structure of the salivary glands rather than only the sites where the proteins were located, and also to the preparation of samples for qPCR, which were ground without separating the acini from the ducts. This may have contributed to the different mean expression values observed among the groups and represented by their respective standard deviations.…”