Expressão de DMP-1, DSPP, VEGF e FGF2 em células derivadas da polpa de dentes decíduos após o uso do laser de baixa intensidade / FGF2, VEGF, DSPP, and DMP-1 expression in cells of the pulp deciduous teeth with a low intensity laser

O objetivo do presente trabalho foi avaliar o efeito de diferentes densidades de energia do Laser de Baixa Intensidade na viabilidade e proliferação celular de fibroblastos derivados da polpa de dentes decíduos humanos e na expressão de RNAm para DMP- 1, DSPP, VEGF e FGF-2. Amostras de fibroblastos pulpares da polpa de dentes decíduos humanos foram obtidas de um Biorrepositório. Foram utilizadas células entre a 4ª e a 7ª passagem, irradiadas com Laser de Baixa Intensidade (InGaAlP) de acordo com os seguintes grupos experimentais: Grupo 1: 1,2 J/cm2 - 05 mW - 10s; Grupo 2: 2,5 J/cm2 - 05 mW - 20s; Grupo 3: 3,7 J/cm2 - 05 mW - 30s; Grupo 4: 5,0 J/cm2 - 05 mW - 40s; Grupo 5: 6,2 J/cm2 - 05 mW - 50s; Grupo 6: 2,5 J/cm2 - 10 mW - 10s; Grupo 7: 3,7 J/cm2 - 15 mW - 10s; Grupo 8: 5,0 J/cm2 - 20 mW - 10s; Grupo 9: 6,2 J/cm2 - 25 mW - 10s; Controle Negativo: DMEM 1% SFB ­ não irradiado; Controle Positivo: DMEM 10% SFB ­ não irradiado. As técnicas utilizadas para as análises de viabilidade e proliferação celular foram MTT e CV. A técnica utilizada para avaliação da expressão de RNAm para os alvos DMP-1, DSPP, VEGF e FGF-2 foi RT-PCR. Os resultados foram analisados pelo método ANOVA a dois critérios, seguido pelo teste de Tukey (p<0,05). Para o teste MTT, na comparação intragrupos observou-se que houve diferença estatisticamente significativa entre os períodos 6h, 12h e 24h, diminuindo a viabilidade com o passar do tempo, exceto para o Grupo 1. Na comparação intergrupos, o MTT mostrou menor viabilidade para o controle negativo em comparação com os outros grupos (p<0,05), exceto com grupo 5 (5mW/50 seg). Observou-se que os grupos com maiores potências (10mW, 15mW, 20mW e 25mW), menores tempos de aplicação (10 segundos) e densidades de energia entre 2,5 J/cm2 e 6,2 J/cm2, apresentaram estatisticamente maior viabilidade que o grupo com menor potência (5mW), maior tempo de aplicação (50 segundos) e densidade de energia de 6,2 J/cm2. Para o teste CV não houve diferença intragrupos, mas houve diferença intergrupos entre os controles positivo e negativo. Para a expressão de RNAm por RTPCR, os fatores de crescimento VEGF e FGF-2 foram expressos em grande quantidade no primeiro período experimental, enquanto que DMP-1 e DSPP não foram expressos de maneira significativa. De acordo com os resultados obtidos, frente as diferentes densidades de energia, sugere-se que a terapia a laser de baixa intensidade manteve os fibroblastos viáveis e aumentou a expressão de RNAm para VEGF e FGF-2.(AU)

This study aimed to evaluate the effect of different energy densities of Low Level Laser (LLL) on cell viability and proliferation of fibroblasts from the pulp of human primary teeth (DHPF) and on the RNAm expression of DMP-1, DSPP, VEGF and FGF-2. DHPF were obtained from a biorepository and used at passages 4th to 7th. The cells were irradiated with LLL (InGaAlP) according to the following experimental groups: Group 1: 1.2 J/cm2 - 05 mW - 10s; Group 2: 2.5 J/cm2 - 05 mW - 20s; Group 3: 3.7 J/cm2 - 05 mW - 30s; Group 4: 5.0 J/cm2 - 05 mW - 40s; Group 5: 6.2 J/cm2 - 05 mW - 50s; Group 6: 2.5 J/cm2 - 10 mW - 10s; Group 7: 3,7 J/cm2 - 15 mW - 10s; Group 8: 5.0 J/cm2 - 20 mW - 10s; Group 9: 6.2 J/cm2 - 25 mW - 10s; Negative Control: DMEM 1% SFB ­ not irradiated; Positive Control: DMEM 10% SFB ­ not irradiated. The techniques used to evaluate the cell viability/proliferation were MTT and Crystal Violet (CV) assays. RT-PCR was used to verify the RNAm expression of DMP-1, DSPP, VEGF, and FGF-2. Two-way ANOVA, followed by Tukey test (p<0.05) was used to analyze the results. In the intragroup comparison, MTT assay revealed statistically significant differences among the periods of 6h, 12h, and 24h, with viability reduction as time went by, except for Group 1. In the intergroup comparison, the MTT assay showed that the negative control had statistically lower viability than that of the other groups (p<0.05), except for Group 5 (5mW/50 s). The groups with higher powers (10mW, 15mW, 20mW, and 25mW), shortest application periods (10 s), and energy densities between 2.5 J/cm2 and 6.2 J/cm2 exhibited statistically higher viability than that of the group with small power (5mW), longer application period (50 s), and energy density of 6.2 J/cm2 . CV assay did not show intergroup statistically differences. In the intragroup comparison, CV assay revealed statistically significant differences between positive and negative controls (p<0.05). RT-PCR revealed increased RNAm expression of the growth factors VEGF and FGF-2 at the first experimental period, while DMP-1 and DSPP was not significant. Based on the results and different energy densities used, LLL maintained DHPF viability and increased the RNAm expression of VEGF and FGF-2.(AU)

Phototherapy up-regulates dentin matrix proteins expression and synthesis by stem cells from human-exfoliated deciduous teeth.

OBJECTIVES: The aim of this study was to evaluate the effects of infrared LED (850nm) irradiation on dentin matrix proteins expression and synthesis by cultured stem cells from human exfoliated deciduous teeth (SHED). METHODS: Near-exfoliation primary teeth were extracted (n=3), and SHED cultures were characterized by immunofluorescence using STRO-1, CD44, CD146, Nanog and OCT3/4 antibodies, before experimental protocol. The SHEDs were seeded (3×10(4) cells/cm(2)) with DMEM containing 10% FBS. After 24-h incubation, the culture medium was replaced by osteogenic differentiation medium, and the cells were irradiated with LED light at energy densities (EDs) of 0 (control), 2, or 4J/cm(2) (n=8). The irradiated SHEDs were then evaluated for alkaline phosphatase (ALP) activity, total protein (TP) production, and collagen synthesis (SIRCOL™ Assay), as well as ALP, collagen type I (Col I), dentin sialophosphoprotein (DSPP), and dentin matrix acidic phosphoprotein (DMP-1) gene expression (qPCR). Data were analyzed by Kruskal-Wallis and Mann-Whitney tests (α=0.05). RESULTS: Increased ALP activity and collagen synthesis, as well as gene expression of DSPP and ALP, were observed for both EDs compared with non-irradiated cells. The ED of 4J/cm(2) also increased gene expression of COL I and DMP-1. CONCLUSIONS: In conclusion, infrared LED irradiation was capable of biostimulating SHEDs by increasing the expression and synthesis of proteins related with mineralized tissue formation, with overall better results for the energy dose of 4J/cm(2). CLINICAL SIGNIFICANCE: Phototherapy is an additional approach for the clinical application of LED in Restorative Dentistry. Infrared LED irradiation of the cavity's floor could biostimulate subjacent pulp cells, improving local tissue healing.

The effect of irradiation and hyperbaric oxygenation (HBO) on extracellular matrix of the condylar cartilage after mandibular distraction osteogenesis in the rabbit.

The effects of irradiation and hyperbaric oxygenation (HBO) on the extracellular matrix of condylar cartilage after mandibular distraction were evaluated. Unilateral distraction was performed on 19 rabbits. Five study groups were included: control, low- and high-dose irradiation, and low- and high-dose irradiation groups with HBO. Additionally, four temporomandibular joints (TMJ) were used as control material. The high-dose irradiated animals were given in the TMJ 22.4 Gy/4 fractions irradiation (equivalent to 50 Gy/25 fractions). Low-dose irradiation group received a 2.2 Gy dosage. Two groups were also given preoperatively HBO 18 x 2.5ATA x 90 min. After a two-week distraction period (14 mm lengthening) and four-week consolidation period the TMJs were removed. Proteoglycan (PG) distribution of the extracellular matrix was evaluated using safranin O staining and collagen I and II using immunohistochemistry. The organization of fibrillar network was studied by polarized light microscopy. On the operated side of the control group and on the unoperated side in all, except for high-dose irradiated group, PG distribution and fibrillar network were normal appearing. In the irradiated groups, with or without HBO, the cartilaginous layer was partially or totally devoid of PG and the network structure was severely damaged. In conclusion, irradiation in conjunction with the pressure applied by distraction causes severe damage to extracellular matrix of condylar cartilage.