Valéria R. G. Sella

Effect of low-level laser therapy on bone repair: a randomized controlled experimental study

The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on bone repair in femoral fractures. Sixty adult Wistar rats were randomly assigned into one of two groups: group A (ostectomy + LLLT) or group B (ostectomy + sham laser). An experimental model of complete bone fracture was surgically created by removing a 2-mm fragment from the middle third of the femoral shaft. Data were analyzed on days 8, 13, and 18 after the fracture (subgroups 1, 2, and 3). Samples were assessed for changes in inflammatory infiltration; trabecular bone matrix, periosteal, and new bone formations; and changes in the expression of particular osteogenic-related proteins (osteocalcin, osteopontin, and osteonectin). Microscopic analysis revealed a significant decrease in inflammatory infiltration, intense trabecular bone matrix and periosteal formation, and an increase in newly formed bone after laser irradiation. We also found an increase in the expression of bone matrix proteins with LLLT, with a significant difference measured for osteocalcin in the LLLT group at day 8 (p = 0.007). We show that LLLT plays an important role in augmenting bone tissue formation, which is relevant to fracture healing. LLLT may therefore be indicated as an adjunct therapeutic tool in clinical practice for the treatment or recovery of nonunion injuries.

Dosimetry of a Carbon Dioxide Laser for Black Tattoo Removal in a Rat Model

OBJECTIVE To determine the optimal parameters of power, energy, and time for the application of a carbon dioxide laser for Tribal Black ink tattoo removal. BACKGROUND DATA The use of antiquated techniques to remove tattoos demonstrates the difficulty of making advances in this field. Studies by the American Society for Dermatologic Surgery have shown that 5% of the global population has at least one tattoo on the body, with 10% of them wanting a tattoo to be removed. Laser removal has been studied and improved as a less invasive and safer method of surgical removal; however, the ideal dosimetry is not yet established. MATERIALS AND METHODS Thirty-three male Wistar rats were anesthetized and tattooed in the dorsal region in a quadrangular manner. The rats were distributed under low/null luminosity for 4 months into three equal and random groups for the application of the laser, namely, G1 (P = 0.6 W, Et = 0.9 J), G2 (P = 0.8 W, Et = 1, 2 J), and G3 (P = 1 W, Et = 1.5 J), with the application time standardized to 0.15 sec with 10 passes per application. The procedure was repeated at intervals of 4 weeks until 10 cycles of laser application were completed. The images were studied using the ImageJ program and histological analysis and subjected to the one-way ANOVA test for Tukeys multiple comparison post-test. RESULTS We observed a significant difference between groups 1 and 3 and between groups 2 and 3. CONCLUSIONS The laser with the parameters of P = 1 W, Et = 1.5 J, and t = 0.15 sec yields better Tribal Black ink removal results.

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

PURPOSE 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 CO2 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/cm2, power of 200mW, power density of 0.2W/cm2, 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.

RT-PCR standardization and bone mineralization after low-level laser therapy on adult osteoblast cells

Purpose: Osteoblasts are capable to produce different compounds directly connected to bone mineralization process. This study aims to standardize the reverse transcriptase polymerase chain reaction (RT-PCR) for adult osteoblasts to observe the effect of low level laser therapy on bone mineralization. Methods: Five-millimeter long fragments obtained from the mead femoral region of male Wistar rats were assigned into group A (n=10, laser) and group B (n=10, no laser), submitted to mechanic and enzymatic digestion. After 7 days, cultures of group A were irradiated daily on a single spot with a GaInAs laser, λ=808nm, 200mW/cm2, 2J/cm2, bean diameter of 0,02mm, 5 seconds for 6 days. Group B was manipulated but received no laser irradiation. After 13 days the cells were trypsinized for 15 minute and stabilized with RNA later® for RNA extraction with Trizol®. cDNA synthesis used 10μg of RNA and M-MLV® enzyme. PCR was accomplished using the β-actin gene as a control. Another aliquot was fixed for Hematoxylin-Eosin and Von Kossa staining to visualize bone mineralization areas. Results: Under UV light we observed clearly the amplification of β-actin gene around 400bp. HE and Von Kossa staining showed osteoblast clusters, a higher number of bone cells and well defined mineralization areas in group A. Conclusion: The cell culture, RNA extraction and RT-PCR method for adult osteoblasts was effective, allowing to use these methods for bone mineralization studies. Laser improved bone mineralization and further studies are needed involving osteogenesis, calcium release mechanisms and calcium related channels.

A visão do ortopedista brasileiro sobre a descarga parcial de peso em ortostase nas fraturas expostas da diáfise da tíbia após osteossíntese

BACKGROUND: Tibial shaft fractures are the most frequent among long bone fractures. They are described in the literature according to the device and method of treatment, with recommendations that range from full weight bearing to non-weight bearing restrictions. There are studies comparing osteosynthesis devices and surgical aspects, but no references were found on how or when to allow weight bearing on the affected limb in the standing position. OBJECTIVES: The present study learned from Brazilian orthopedists which methods of osteosynthesis they use to treat open tibial fractures, whether they refer patients to physical therapy, when and why they allow partial weight bearing for both physical activity and therapy. METHODS: Two hundred and thirty-five orthopedists answered a questionnaire during the 14th Brazilian Conference of Orthopedic Trauma. Results: The results showed that, in Brazil, the most widely used osteosynthesis device is the external fixator, but earlier weight bearing while standing occurs when intramedullary nails are used. Most orthopedists refer patients to physical therapy and allow partial weight bearing in the standing position according to the material used for synthesis. CONCLUSIONS: It was concluded that there is a preference for external fixation, that most orthopedists refer patients to physical therapy and that the synthesis material influences restrictions on partial weight bearing.