Comparison of two different biomaterials in the bone regeneration (15, 30 and 60 days) of critical defects in rats

ABSTRACT Purpose To evaluate and compare two types of different scaffolds in critical bone defects in rats. Methods Seventy male Wistar rats (280 ± 20 grams) divided into three groups: control group (CG), untreated animals; biomaterial group 1 (BG1), animals that received the scaffold implanted hydroxyapatite (HA)/poly(lactic-co-glycolic) acid (PLGA); and biomaterial group 2 (BG2), animals that received the scaffolds HA/PLGA/Bleed. The critical bone defect was induced in the medial region of the skull calotte with the aid of an 8-mm-diameter trephine drill. The biomaterial was implanted in the form of 1.5 mm thick scaffolds, and samples were collected after 15, 30 and 60 days. Non-parametric Mann-Whitney test was used, with the significance level of 5% (p ≤ 0.05). Results Histology revealed morphological and structural differences of the neoformed tissue between the experimental groups. Collagen-1 (Col-1) findings are consistent with the histological ones, in which BG2 presented the highest amount of fibers in its tissue matrix in all evaluated periods. In contrast, the results of receptor activator of nuclear factor kappa-Β ligand (Rank-L) immunoexpression were higher in BG2 in the periods of 30 and 60 days, indicating an increase of the degradation of the biomaterial and the remodeling activity of the bone. Conclusions The properties of the HA/PLGA/Bleed scaffold were superior when compared to the scaffold composed only by HA/PLGA.

Eficácia da terapia a laser de baixa intensidade no controle da dor neuropática em camundongos / Eficacia de la terapia láser de baja potencia en el control del dolor neuropático en ratones / Low intensity laser therapy effectiveness in controlling neuropathic pain in mice

RESUMO A terapia a laser de baixa intensidade (LLLT) vem sendo amplamente discutida na literatura como forma alternativa de tratamento para diversos tipos de dor, com destaque para a neuropática. Essa terapia sobressai pelo fato de não ser invasiva, raramente causar efeitos colaterais e ser de baixo custo. Em contrapartida, para sua eficácia, é necessário o detalhamento dos parâmetros, que ainda são muito discrepantes na literatura. Assim, este trabalho tem como objetivo investigar o efeito da LLLT, na faixa do infravermelho, com fluência de 30J/cm², no controle da dor neuropática em modelo animal. Foram utilizados 24 camundongos da cepa suíço albino, machos, pesando 25­30 gramas, divididos em três grupos: Grupo Placebo (GP), Grupo Laser (GL30) e Grupo Sham (GS). A indução da neuropatia foi feita através do modelo de constrição crônica do nervo isquiático (CCI), e o tratamento da LLLT realizou-se da seguinte maneira: GP com o laser com fluência de 0J/cm2, GL30 tratado com fluência de 30J/cm2, e GS com simulação de cirurgia sem intervenção. Executaram-se as irradiações 3 vezes por semana, durante 90 dias, no ponto de compressão do nervo, utilizando-se a técnica de contato. A fins de avaliação, foram utilizados o teste da placa quente, para hiperalgesia térmica, e o Teste de Randall-Selitto para hiperalgesia mecânica. Nos resultados do GP, observamos que não houve melhora significativa nos dias após a cirurgia em nenhum dos testes realizados e, no GL30, observou-se uma melhora expressiva em ambos os testes a partir do 30º dia de tratamento para o teste de Placa Quente e a partir do 45º para o Randall-Selitto, em que os camundongos apresentaram restauração total da sensibilidade. Concluímos, pois, que a utilização de LLLT com fluência de 30J/cm2 no tratamento da dor neuropática em modelo animal é eficaz.

RESUMEN La terapia láser de baja potencia (LLLT) ha sido ampliamente discutida en la literatura como forma alternativa de tratamiento para muchos tipos de dolor, especialmente para el neuropático. Esa terapia se destaca por el hecho de no ser invasiva, raramente causar efectos secundarios y ser de bajo costo. En cambio, para su eficacia, es necesario que se presenten los detalles de los parámetros, que todavía son muy discordantes en la literatura. Así, este trabajo tiene como objetivo investigar el efecto de la LLLT, en el rango del infrarrojo, con fluidez de 30 J/cm², en el control del dolor neuropático en modelos animales. Se utilizaron 24 ratones de la cepa suizo-albino, machos, con peso de 2530 gramos, divididos en tres grupos: Grupo Placebo (GP), Grupo Láser (GL30) y Grupo Sham (GS). Se llevó a cabo la inducción de la neuropatía por medio del modelo de constricción crónica del nervio isquiático y se realizó el tratamiento de la LLLT como sigue: GP con el láser con fluidez de 0 J/cm2, GL30 con fluidez de 30 J/cm2, y GS con simulación de cirugía sin intervención. Se realizaron las irradiaciones tres veces por semana, durante 90 días, en el punto de compresión del nervio, utilizándose la técnica de contacto. A efectos de evaluación, se utilizaron la prueba de placa caliente para hiperalgesia térmica y la prueba de Randall y Selitto para hiperalgesia mecánica. En los resultados del GP, observamos que no hubo mejora significativa en los días después de la cirugía en ninguna de las pruebas realizadas y, en el GP30, se verificó mejora significativa en ambas pruebas: desde el 30.º día de tratamiento para la prueba de placa caliente y desde el 45.º día para la prueba de Randall y Selitto, en que los ratones presentaron restauración total de la sensibilidad. Concluimos, por lo tanto, que el uso de la LLLT con fluidez de 30 J/cm2 en el tratamiento del dolor neuropático en modelos animales es efectivo.

ABSTRACT Low-level laser therapy (LLLT) has been widely discussed in the literature as an alternative form of treatment for several types of pain, especially neuropathic pain. This kind of therapy stands out for not being invasive, rarely causing side effects and being cost effective. However, for its effectiveness, it is necessary more detailed parameters, which are still very discrepant in the literature. Thus, this study aims to investigate the effect of LLLT, in the infrared range, with 30J/cm² fluency, on the control of neuropathic pain in animal models. A total of 24 male Swiss albino mice, weighing 25.30 grams, were divided into three groups: the Control Group (CG), the Laser Group (L30G) and the Sham Group (SG). The induction of neuropathy was held through the model of chronic constriction of the sciatic nerve (CCI), and the LLLT treatment was conducted as follows: The CG was treated with 0 J/cm2 fluency, whereas the L30G was treated with 30 J/cm2 fluency, and the SG with simulation of surgery without intervention. The irradiations were performed 3 times a week, for 90 days, at the nerve's point of compression, using the contact technique. For the evaluation, the Hot Plate Test was used for thermal hyperalgesia, and the Randall-Selitto test was used for mechanical hyperalgesia. In the CG's results, we observed no significant improvement in the days after surgery in any of the tests conducted, and, in the GL30, a significant improvement in both tests was observed: from the 30th day of treatment for the Hot Plate Test, and from the 45th for the Randall-Selitto Test, in which the mice showed total restoration of sensitivity. We thus conclude that the use of LLLT with 30 J/cm2 fluency in the treatment of neuropathic pain in animal models is effective.

Alternative animal model for studies of total skin thickness burns

Abstract Purpose: To present an alternative experimental model of third degree burn of easy reproducibility. Methods: Eighteen male Wister rats were randomly divided into three groups, 6 of which were allocated to each group. A soldering iron coupled to an aluminum plate was used to produce burn, at a temperature of 150ºC, with different exposure times per group. Group 5 (G5) animals were burned at 150°C with exposure time of 5 seconds; Group 10 (G10) the animals were burned at 150°C with exposure time of 10 seconds and group 15 (G15) the animals were burned at 150°C with exposure time of 15 seconds. Results: Histopathological analyzes showed that all three groups had similar morphological characteristics, with total thickness involvement. Conclusion: The technique is effective to reproduce a third degree burn and suggests the temperature of 150ºC with 5 seconds of exposure in order to minimize the risks to the animals.