RESUMO
The objective of this study was to evaluate, in vitro, the bactericidal effect of AmPDT on Staphylococcus aureus (ATCC 25923) using different concentrations (100, 50, 25, 12.5 and 6.25µg/mL) of phenothiazine compound combined with LED light (λ632±2nm) using varied energy densities (12, 9.6, 7.2, 4.8 and 2.4J/cm2). The experiments were carried out in triplicate and the samples were divided into groups: Control, Irradiated (treated only with light at different energy densities), Photosensitizer (treated only in the presence of the dye), AmPDT (treatment with light associated with dye). Counts of the colony forming units and the data obtained were statistically analyzed (ANOVA, Tukey's test, p<0.05). The results showed no difference between irradiated and Control groups. However, using the photosensitizer alone caused significant increased cytotoxicity and consequent reduction on the CFU counts (12.5µg/mL (p<0.001), 25µg/mL, 50µg/mL and 100µg/mL (p<0.0001). When AmPDT was used significant inhibition above 70% were detected for all concentrations of the photosensitize (p<0.0001) except for 6.25µg/mL. The results indicate a dose-response dependent when the photosensitizer is used alone but not for the sole use of the light is used. It is concluded that, a single application of AmPDT, using energy density of 12J/cm2 associated either to 12.5 (81.52%) or 25µg/mL (91.57%) resulted in higher in vitro inhibition of S. aureus.
Assuntos
Anti-Infecciosos/farmacologia , Luz , Fenotiazinas/química , Fármacos Fotossensibilizantes/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Anti-Infecciosos/química , Corantes/química , Corantes/farmacologia , Testes de Sensibilidade Microbiana , Fenotiazinas/farmacologia , Fármacos Fotossensibilizantes/química , Staphylococcus aureus/efeitos da radiação , TermodinâmicaRESUMO
The treatment of bone loss due to different etiologic factors is difficult and many techniques aim to improve the repair, including a wide range of biomaterials and recently, photobioengineering. This work aimed to assess by histological analysis the repair of bone defects grafted with biphasic synthetic micro-granular HA + ß-TCP associated with LED phototherapy. Forty rats were divided into 4 groups (Clot, LED, Biomaterial and LED + Biomaterial) each subdivided into 2 subgroups according to the time of animal death (15 and 30 days). Surgical bone defects were prepared on the femur of each animal with a trephine drill. In animals of the Clot group the defect was filled only by blood clot, in the LED group the defect filled with the clot was further irradiated. In the animals of Biomaterial and LED + Biomaterial groups the defect was filled by biomaterial and the last one was further irradiated (λ = 850 ± 10 nm, 150 mW, Φ ~ 0.5 cm2, 20 J/cm2 - session, 140 J/cm2- treatment) at 48-h intervals for 2 weeks. Following animal death, samples were taken and analyzed by light microscopy. Using the degree of maturation of the bone by assessment of the deposition/organization of the basophilic lines in the newly formed bone tissue, the LED + Biomaterial group was the one in a more advanced stage of bone repair process at the end of the experiment. It may be concluded that the use of LED phototherapy was effective in positively modulating the process of bone repair of bone defects in the femur of rats submitted or not to biomaterial grafting.
Assuntos
Fosfatos de Cálcio/farmacologia , Durapatita/farmacologia , Terapia com Luz de Baixa Intensidade/métodos , Tíbia/cirurgia , Animais , Materiais Biocompatíveis/farmacologia , Substitutos Ósseos/farmacologia , Masculino , Ratos , Ratos Wistar , Tíbia/efeitos da radiação , Cicatrização/efeitos da radiaçãoRESUMO
The treatment of bone loss due to different etiologic factors is difficult and many techniques aim to improve the repair, including a wide range of biomaterials and recently, photobioengineering. This work aimed to assess by histological analysis the repair of bone defects grafted with biphasic synthetic micro-granular HA + β-TCP associated with LED phototherapy. Forty rats were divided into 4 groups (Clot, LED, Biomaterial and LED + Biomaterial) each subdivided into 2 subgroups according to the time of animal death (15 and 30 days). Surgical bone defects were prepared on the femur of each animal with a trephine drill. In animals of the Clot group the defect was filled only by blood clot, in the LED group the defect filled with the clot was further irradiated. In the animals of Biomaterial and LED + Biomaterial groups the defect was filled by biomaterial and the last one was further irradiated (λ=850±10 nm, 150 mW, Φ ~ 0.5 cm2, 20 J/cm2 - session, 140 J/cm2- treatment) at 48-h intervals for 2 weeks. Following animal death, samples were taken and analyzed by light microscopy. Using the degree of maturation of the bone by assessment of the deposition/organization of the basophilic lines in the newly formed bone tissue, the LED + Biomaterial group was the one in a more advanced stage of bone repair process at the end of the experiment. It may be concluded that the use of LED phototherapy was effective in positively modulating the process of bone repair of bone defects in the femur of rats submitted or not to biomaterial grafting.
O tratamento de perdas ósseas devido a diferentes fatores etiológicos é difícil e muitas técnicas têm por objetivo melhorar o reparo incluindo o uso de uma ampla gama de biomateriais e, recentemente, a fotobioengenharia. Este trabalho teve como objetivo avaliar, por meio de análise histológica, o reparo de defeitos ósseos enxertados com HA bifásica micro-granular sintética + β -TCP associada à fototerapia LED. Quarenta ratos foram divididos em quatro grupos (Clot, LED, Biomaterial e LED + Biomaterial), subdivididos no dois subgrupos de acordo com o momento da morte (15 e 30 dias). Defeitos ósseos cirúrgicos foram criados em um fêmur de cada animal com uma broca trefina. Em animais do grupo coágulo, o defeito foi preenchido apenas pelo coágulo sanguíneo, no grupo de LED o defeito foi preenchido pelo coágulo e irradiado. Nos animais dos grupos do biomaterial e LED + biomaterial, os defeitos foram preenchidos com biomaterial e o último foi adicionalmente irradiado (λ=850±10 nm, 150 mW, Φ ~ 0.5 cm2, 20 J/cm2 - session, 140 J/cm2 -tratamento) a cada 48 h por duas semanas. Após a morte dos animais, amostras foram colhidas e analisadas por microscopia de luz, usando o grau de maturação do osso como marcador (deposição/organização das linhas basofílicas) no tecido ósseo neoformado. O grupo de LED + biomaterial apresentou processo de reparação mais avançado ao fim do experimento. Pode-se concluir que o uso da fototerapia LED foi eficaz na modulação positiva do processo de reparo ósseo de defeitos ósseos no fêmur de ratos submetidos ou não a enxerto com biomaterial.
Assuntos
Animais , Masculino , Ratos , Fosfatos de Cálcio/farmacologia , Durapatita/farmacologia , Terapia com Luz de Baixa Intensidade/métodos , Tíbia/cirurgia , Materiais Biocompatíveis/farmacologia , Substitutos Ósseos/farmacologia , Ratos Wistar , Tíbia/efeitos da radiação , Cicatrização/efeitos da radiaçãoRESUMO
Use of biomaterials and light on bone grafts has been widely reported. This work assessed the influence of low-level laser therapy (LLLT) on bone volume (BV) and bone implant contact (BIC) interface around implants inserted in blocks of bovine or autologous bone grafts (autografts), irradiated or not, in rabbit femurs. Twenty-four adult rabbits were divided in 8 groups: AG: autograft; XG: xenograft; AG/L: autograft + laser; XG/L: xenograft + laser; AG/I: autograft + titanium (Ti) implant; XG/I: xenograft + Ti implant; AG/I/L: autograft + Ti implant + laser; and XG/I/L: xenograft + Ti implant + laser. The animals received the Ti implant after incorporation of the grafts. The laser parameters in the groups AG/L and XG/L were λ=780 nm, 70 mW, CW, 21.5 J/cm 2 , while in the groups AG/I/L and XG/I/L the following parameters were used: λ=780 nm, 70 mW, 0.5 cm 2 (spot), 4 J/cm 2 per point (4), 16 J/cm 2 per session, 48 h interval × 12 sessions, CW, contact mode. LLLT was repeated every other day during 2 weeks. To avoid systemic effect, only one limb of each rabbit was double grafted. All animals were sacrificed 9 weeks after implantation. Specimens were routinely stained and histomorphometry carried out. Comparison of non-irradiated and irradiated grafts (AG/L versus AG and XG/L versus XG) showed that irradiation increased significantly BV on both grafts (p=0.05, p=0.001). Comparison between irradiated and non-irradiated grafts (AG/I/L versus AG/I and XG/I/L versus XG/I) showed a significant (p=0.02) increase of the BIC in autografts. The same was seen when xenografts were used, without significant difference. The results of this investigation suggest that the use of LLLT is effective for enhancing new bone formation with consequent increase of bone-implant interface in both autologous grafts and xenografts.
Assuntos
Autoenxertos/transplante , Transplante Ósseo/métodos , Implantes Dentários , Xenoenxertos/transplante , Terapia com Luz de Baixa Intensidade/métodos , Osteogênese/fisiologia , Animais , Autoenxertos/patologia , Autoenxertos/efeitos da radiação , Bovinos , Materiais Dentários/química , Planejamento de Prótese Dentária , Feminino , Fêmur/patologia , Fêmur/cirurgia , Xenoenxertos/patologia , Xenoenxertos/efeitos da radiação , Tamanho do Órgão , Osseointegração/fisiologia , Osseointegração/efeitos da radiação , Osteogênese/efeitos da radiação , Coelhos , Dosagem Radioterapêutica , Titânio/químicaRESUMO
Use of biomaterials and light on bone grafts has been widely reported. This work assessed the influence of low-level laser therapy (LLLT) on bone volume (BV) and bone implant contact (BIC) interface around implants inserted in blocks of bovine or autologous bone grafts (autografts), irradiated or not, in rabbit femurs. Twenty-four adult rabbits were divided in 8 groups: AG: autograft; XG: xenograft; AG/L: autograft + laser; XG/L: xenograft + laser; AG/I: autograft + titanium (Ti) implant; XG/I: xenograft + Ti implant; AG/I/L: autograft + Ti implant + laser; and XG/I/L: xenograft + Ti implant + laser. The animals received the Ti implant after incorporation of the grafts. The laser parameters in the groups AG/L and XG/L were λ=780 nm, 70 mW, CW, 21.5 J/cm 2 , while in the groups AG/I/L and XG/I/L the following parameters were used: λ=780 nm, 70 mW, 0.5 cm 2 (spot), 4 J/cm 2 per point (4), 16 J/cm 2 per session, 48 h interval × 12 sessions, CW, contact mode. LLLT was repeated every other day during 2 weeks. To avoid systemic effect, only one limb of each rabbit was double grafted. All animals were sacrificed 9 weeks after implantation. Specimens were routinely stained and histomorphometry carried out. Comparison of non-irradiated and irradiated grafts (AG/L versus AG and XG/L versus XG) showed that irradiation increased significantly BV on both grafts (p=0.05, p=0.001). Comparison between irradiated and non-irradiated grafts (AG/I/L versus AG/I and XG/I/L versus XG/I) showed a significant (p=0.02) increase of the BIC in autografts. The same was seen when xenografts were used, without significant difference. The results of this investigation suggest that the use of LLLT is effective for enhancing new bone formation with consequent increase of bone-implant interface in both autologous grafts and xenografts.
O uso de biomateriais e luz em enxertos ósseos têm sido relatados. Esse trabalho avaliou a influência do laser baixa potência - LBP no volume ósseo (VO) e superfície de contato osso-implante (COI) ao redor de implantes dentários inseridos em blocos de enxerto bovino ou autólogos incorporados, irradiados ou não, em fêmures de coelho. Vinte e quatro coelhos adultos foram divididos em 8 grupos: EA: enxerto autólogo; EX: enxerto xenógeno; EA/L: enxerto autólogo + laser; EX/L: enxerto xenógeno + laser; EA/I: enxerto autólogo + implante; EX/I: enxerto xenógeno + implante; EA/I/L: enxerto autólogo + implante de titânio + laser; EX/I/L: enxerto xenógeno + implante de titânio + laser. Os animais receberam um implante de titânio após a incorporação dos enxertos. Os parâmetros de laser nos grupos EA/L e EX/L foram λ =780 nm, 70 mW, CW, 21,5 J/cm 2 ), enquanto que nos grupos EA/I/L e EX/I/L os seguintes parâmetros de laser foram utilizados: λ =780 nm, 70 mW, 0,5 cm 2 (spot), 4 J/cm 2 por ponto (4), 16 J/cm 2 por sessão, intervalo de 48 h × 12 sessões, CW, modo contato. O LBP foi repetido a cada 48 h (2 semanas). Para evitar efeito sistêmico apenas um membro de cada coelho foi duplamente enxertado. Todos os animais foram sacrificados 9 semanas após o implante. Os espécimes foram corados rotineiramente e histomorfometria foi realizada. A comparação dos enxertos não-irradiados e irradiados (EA/L versus EA e EX/L versus EX) mostrou que a irradiação aumentou significantemente (p=0,02) o VO para ambos os tipos de enxertos (p=0,05, p=0,001). A comparação dos enxertos não-irradiados e irradiados (EA/I/L versus EA/I e EX/I/L versus EX/I) mostrou um aumento significante (p=0,02) do COI nos enxertos autólogos e xenógenos sem diferença estatística. Os resultados desta investigação sugerem que o uso de LBP é efetivo para aumentar a neoformação óssea com consequente aumento do COI em enxertos autólogos e xenógenos.