RESUMEN

Phototherapy has demonstrated positive effects in the treatment of peripheral nerve injury, but there is a need to investigate the dosimetric parameters. Thus, the aim of the present study was to conduct a literature review on the effects of photobiomodulation with the use of low-level laser therapy (LLLT) on the treatment of peripheral nerve injury in experimental models. The databases of PubMed/MEDLINE, SCOPUS, and SPIE Digital Library were searched for articles on the use of LLLT in experimental models of peripheral nerve injury published in English between January 2007 and March 2016. The laser parameter variability was wavelength (632.8 to 980 nm), power (10 to 190 mW), and total energy (0.15 to 90 J) in pulsed or continuous wave and single or multiple points. Eighteen original articles demonstrating the effects of LLLT on the acceleration of functional recovery, morphological aspects as well as the modulation of the expression inflammatory cytokines, and growth factors were selected. LLLT is a viable phototherapeutic modality for the treatment of peripheral nerve injury, demonstrating positive effects on the neuromuscular repair process using either red or infrared light. The majority of studies used a power of up to 50 mW and total energy of up to 15 J administered to multiple points. The determination of these parameters is important to the standardization of a LLLT protocol to enhance the regeneration process following a peripheral nerve injury.

Asunto(s)

Terapia por Luz de Baja Intensidad/métodos , Traumatismos de los Nervios Periféricos/radioterapia , Animales , Modelos Animales de Enfermedad , Regeneración Nerviosa/efectos de la radiación , Recuperación de la Función

RESUMEN

Bioactive glasses (BGs) are known for their ability to bond to living bone and cartilage. In general, they are readily available in powder and monolithic forms, which are not ideal for the optimal filling of bone defects with irregular shapes. In this context, the development of BG-based scaffolds containing flexible fibres is a relevant approach to improve the performance of BGs. This study is aimed at characterizing a new, highly porous, fibrous glassy scaffold and evaluating its in vitro and in vivo biocompatibility. The developed scaffolds were characterized in terms of porosity, mineralization and morphological features. Additionally, fibroblast and osteoblast cells were seeded in contact with extracts of the scaffolds to assess cell proliferation and genotoxicity after 24, 72 and 144 h. Finally, scaffolds were placed subcutaneously in rats for 15, 30 and 60 days. The scaffolds presented interconnected porous structures, and the precursor bioglass could mineralize a hydroxyapatite (HCA) layer in simulated body fluid (SBF) after only 12 h. The biomaterial elicited increased fibroblast and osteoblast cell proliferation, and no DNA damage was observed. The in vivo experiment showed degradation of the biomaterial over time, with soft tissue ingrowth into the degraded area and the presence of multinucleated giant cells around the implant. At day 60, the scaffolds were almost completely degraded and an organized granulation tissue filled the area. The results highlight the potential of this fibrous, glassy material for bone regeneration, due to its bioactive properties, non-cytotoxicity and biocompatibility. Future investigations should focus on translating these findings to orthotopic applications. Copyright © 2015 John Wiley & Sons, Ltd.

Asunto(s)

Materiales Biocompatibles/farmacología , Vidrio/química , Ensayo de Materiales/métodos , Andamios del Tejido/química , Animales , Calcificación Fisiológica/efectos de los fármacos , Muerte Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Concentración de Iones de Hidrógeno , Masculino , Ratones , Pruebas de Mutagenicidad , Osteoblastos/citología , Osteoblastos/efectos de los fármacos , Porosidad , Ratas Wistar , Espectroscopía Infrarroja por Transformada de Fourier , Tejido Subcutáneo/patología

RESUMEN

The aims of this study were to characterize different BS/PLGA composites for their physicochemical and morphological characteristics and evaluate the in vitro and in vivo biological performance. The physicochemical and morphological modifications were analyzed by pH, mass loss, XRD, setting time, and SEM. For in vitro analysis, the osteoblast and fibroblast viability was evaluated. For in vivo evaluations, histopathology and immunohistochemistry were performed in a tibial defect in rats. After incubation, all composites presented lower values in pH and mass loss over time. Moreover, XRD and SEM analysis confirmed that the composites degraded over time. Additionally, pore formation was observed by SEM analysis after incubation mainly in BS/PLGA groups. BS/PLGA showed significantly increased in osteoblast viability 24 h. Moreover, BS/PLGA composites demonstrated an increase in fibroblast viability in all periods analyzed when compared to BS. In the in vivo study, after 2 and 6 weeks of implantation of biomaterials, histopathological findings revealed that the BS/PLGA composites degrades over time, mainly at periphery. Moreover, can be observed the presence of granulation tissue, bone formation, Runx-2, and RANKL immunoexpression in all groups. In conclusion, BS/PLGA composites present appropriate physicochemical characteristics, stimulate the cellular viability, and enhance the bone repair in vivo. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1063-1074, 2017.

Asunto(s)

Ácido Láctico , Ensayo de Materiales , Osteoblastos/metabolismo , Ácido Poliglicólico , Silicatos , Tibia/metabolismo , Fracturas de la Tibia/terapia , Animales , Línea Celular , Supervivencia Celular/efectos de los fármacos , Fibroblastos/citología , Fibroblastos/patología , Concentración de Iones de Hidrógeno , Ácido Láctico/química , Ácido Láctico/farmacología , Ratones , Osteoblastos/patología , Osteogénesis/efectos de los fármacos , Ácido Poliglicólico/química , Ácido Poliglicólico/farmacología , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Ratas , Silicatos/química , Silicatos/farmacología , Tibia/patología , Fracturas de la Tibia/metabolismo , Fracturas de la Tibia/patología

RESUMEN

Oxidative stress is present in severe asthma and contributes to the low response to corticoids through the downregulation of histone deacetylase (HDAC) and the increase of cytokines. Low-level laser therapy (LLLT) has been proven to be an anti-inflammatory. Thus, we investigated the laser effect on lipopolysaccharide (LPS)-induced cytokine secretion and HDAC activity in U937 cells under oxidative stress. U937 cells activated with oxidative stress were treated with dexamethasone (dexa) or laser. Cytokines and phosphoinositide 3-kinase (PI3K) were measured by ELISA whilst the HDAC was detected through colorimetric assay. LPS activated- U937 cells cytokines secretion increased with H2O2 (hydrogen peroxide) as well as with TSA (trichostatin). The HDAC activity in activated U937 cells was decreased. LLLT and dexa inhibited the LPS-stimulated U937 cells cytokines, but dexa effect disappeared with H2O2. With TSA, the LLLT was less effective on H2O2/LPS stimulated- U937 cells cytokines. Dexa failed on H2O2/LPS- induced HDAC, while LLLT restored the HDAC and the dexa effect. LLLT plus prostaglandin E2 (PGE2) increased cyclic adenosine monophosphate (cAMP) and potentiated the laser action on oxidative stress-induced cytokine. LLLT reduced the PI3K and its effects on cytokine and HDAC was suppressed with LY294002. In situations of corticoid resistance, LLLT acts decreasing the cytokines and HDAC through the activation of the protein kinase A via the inhibition of PI3K.

Asunto(s)

Resistencia a Medicamentos , Glucocorticoides , Terapia por Luz de Baja Intensidad , Estrés Oxidativo , AMP Cíclico/metabolismo , Proteínas Quinasas Dependientes de AMP Cíclico/metabolismo , Dexametasona/farmacología , Glucocorticoides/farmacología , Histona Desacetilasas/metabolismo , Humanos , Interleucina-8/metabolismo , Lipopolisacáridos , Macrófagos Alveolares/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Células U937

RESUMEN

The treatment of muscle injuries is a common practice at rehabilitation centers. Low-level laser therapy (LLLT) has demonstrated positive effects regarding the modulation of the inflammatory response, the enhancement of the tissue repair process and the prevention of fibrosis. The aim of the present study was to evaluate the effects of LLLT on morphological aspects of muscle tissue, collagen remodeling and activity of matrix metalloproteinase 2 (MMP-2) in rat skeletal muscle following acute injury. Wistar rats were divided into five groups: (1) control group (n = 10), (2) sham group (n = 10), (3) LLLT group (n = 30), (4) non-treated injury group (n = 30) and (5) injury + LLLT group (n = 30). Cryoinjury was performed on the belly of the tibialis anterior (TA) muscle. LLLT was performed daily with an AlGaAs laser (780 nm; beam spot of 0.04 cm(2), output power of 40 mW, power density of 1 W/cm(2), energy density of 10 J/cm(2) and 10-s exposure time). Animals were euthanized at 1, 3 and 7 days. The TA muscles were removed and weighed. Morphological aspects were evaluated using H & E staining. The amount and distribution of collagen fibers were evaluated by picrosirius staining. Characterization and activity of MMP-2 were evaluated by zymography and Western blot techniques, respectively. The results revealed that LLLT induced a reduction in inflammatory infiltrate and myonecrosis after 1 day, an increase in the number of blood vessels after 3 and 7 days as well as an increase in the number of immature muscle fibers and MMP-2 gelatinase activity after 7 days. In conclusion, LLLT has a positive effect on the inflammatory process, MMP2 activity and collagen organization and distribution in the repair process of rat skeletal muscle.

Asunto(s)

Terapia por Luz de Baja Intensidad/métodos , Músculo Esquelético/lesiones , Tibia/patología , Animales , Colágeno/metabolismo , Fibrosis/radioterapia , Masculino , Metaloproteinasa 2 de la Matriz/metabolismo , Músculo Esquelético/patología , Ratas Wistar

RESUMEN

This study analyzed the effect of nandrolone decanoate (ND) on muscle repair and the expression of myogenic regulatory factors following cryoinjury in rat skeletal muscle. Adult male Wistar rats were randomly divided into 4 groups: control group, sham group, cryoinjured group treated with ND and non-injured group treated with ND. Treatment consisted of subcutaneous injections of ND (5 mg/kg) twice a week. After sacrifice, the tibialis anterior muscle was removed for the isolation of total RNA and analysis of myogenic regulatory factors using real-time PCR as well as morphological analysis using the hematoxylin-eosin assay. There was a significant increase in MyoD mRNA after 7 days and in myogenin mRNA after 21 days in the cryoinjured ND group in comparison to other groups in the same period. The morphological analysis revealed no edema or myonecrosis after 7 days as well as no edema or inflammatory infiltrate after 14 days in the cryoinjured ND group. In conclusion the anabolic steroid nandrolone decanoate can modulate the muscle repair process in rats following cryoinjury by influencing the expression of regulatory myogenic factors and phases of muscle repair.

Asunto(s)

Anabolizantes/farmacología , Músculo Esquelético/efectos de los fármacos , Nandrolona/análogos & derivados , Anabolizantes/administración & dosificación , Animales , Modelos Animales de Enfermedad , Regulación de la Expresión Génica/efectos de los fármacos , Inyecciones Subcutáneas , Masculino , Músculo Esquelético/lesiones , Músculo Esquelético/patología , Proteína MioD/genética , Factores Reguladores Miogénicos/genética , Nandrolona/administración & dosificación , Nandrolona/farmacología , Nandrolona Decanoato , ARN/metabolismo , Distribución Aleatoria , Ratas , Ratas Wistar , Reacción en Cadena en Tiempo Real de la Polimerasa , Factores de Tiempo

RESUMEN

AIM: The aim of the present study was to perform a comparative analysis of occlusal contact points in children with and without signs and symptoms of Temporomandibular Disorders (TMD). STUDY DESIGN: Cross-sectional study. One hundred fifty children between 6 and 14 years of age were evaluated using the Helkimo questionnaire and a clinical exam. The occlusal contact points in each child were recorded during maximal intercuspation with the aid of carbon strips. Digital photographs were taken of the upper and lower arches before and after recording the occlusal contacts. The number of contact points between sides were compared and recorded on individual charts (occlusograms). STATISTICS: Student's t-test and Pearson's chi-square test were used for the statistical analysis, with the level of significance set at 0.05, which revealed no statistically significant differences between genders. The Student's t-test revealed a statistically significant difference in the mean number of occlusal contact points between the participants with and without TMD, with a higher number of contact points among those without TMD. There was no significant difference between sides. RESULTS The results of this study show a difference in the number of occlusal contact points in centric occlusion between children with and without TMD. CONCLUSION Regardless of the degree of severity, the number of occlusal contact points is lower among children with TMD.

Asunto(s)

Oclusión Dental Céntrica , Registro de la Relación Maxilomandibular , Trastornos de la Articulación Temporomandibular/patología , Adolescente , Niño , Estudios Transversales , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Registro de la Relación Maxilomandibular/instrumentación , Masculino , Músculos Masticadores/patología , Músculos del Cuello/patología , Palpación , Fotografía Dental/métodos , Proyectos Piloto , Rango del Movimiento Articular/fisiología , Articulación Temporomandibular/patología , Trastornos de la Articulación Temporomandibular/diagnóstico

RESUMEN

ALT-C, an ECD motif (glutamic acid, cysteine, aspartic acid) disintegrin from Bothrops alternatus snake venom, induces alfa2beta1 integrin-mediated signaling and neutrophil chemotaxis. In vitro, in human umbilical vein endothelial cells (HUVEC), ALT-C induces cell proliferation, thus showing an interesting potential for tissue regeneration studies. This work aimed to evaluate the influence of ALT-C in myoblast viability and differentiation. Myoblasts were obtained from hind limb muscles of 3 to 4-day old Wistar rats. The cells were incubated with ALT-C at different concentrations and incubation periods were followed by total RNA isolation. cDNA synthesis and real time polymerase chain reaction (PCR) were performed with primers of myoD as well as of both (slow and fast) myosin heavy chain isoforms (MHC). ECD-disintegrin increased myoblast viability in a dose-dependent way, mostly with 50 to 100 nM concentrations, and such effect was more prevalent after 48 hours. No changes in gene expression of both MHC isoforms were observed in ALT-C-treated cells. MyoD expression was not detected, which suggests that myoblasts were in mature stages. Protease activity and cytokine array tested in a medium of 50 nM ALT-C-treated cells after 48 hours were not different from controls. In conclusion, it was shown that myoblats are sensitive to ALT-C indicating an integrin-mediated intracellular signaling that increases cell viability.

Asunto(s)

Bothrops , Venenos de Crotálidos , Ácido Glutámico , Mioblastos Esqueléticos