Effects of photobiomodulation on experimental models of peripheral nerve injury.

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.

Biosilicate/PLGA osteogenic effects modulated by laser therapy: In vitro and in vivo studies.

The main purpose of the present work was to evaluate if low laser level therapy (LLLT) can improve the effects of Biosilicate®/PLGA (BS/PLGA) composites on cell viability and bone consolidation using a tibial defects of rats. The composites were characterized by scanning electron microscope (SEM) and reflection Fourier transform infrared spectrometer (FTIR). For the in vitro study, fibroblast and osteoblast cells were seeded in the extract of the composites irradiated or not with LLLT (Ga-Al-As, 808nm, 10J/cm2) to assess cell viability after 24, 48 and 72h. For the in vivo study, 80 Wistar rats with tibial bone defects were distributed into 4 groups (BS; BS+LLLT; BS/PLGA and BS/PLGA+LLLT) and euthanized after 2 and 6weeks. Laser irradiation Ga-Al-As (808nm, 30J/cm2) in the rats was performed 3 times a week. The SEM and FTIR results revealed that PLGA were successfully inserted into BS and the microparticles degraded over time. The in vitro findings demonstrated higher fibroblast viability in both BS/PLGA groups after 24h and higher osteoblast viability in BS/PLGA+LLLT in all periods. As a conclusion, animals treated with BS/PLGA+LLLT demonstrated an improved material degradation and an increased amount of granulation tissue and newly formed bone.

Characterization and biological evaluation of the introduction of PLGA into biosilicate®.

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.

Characterization and biocompatibility of a fibrous glassy scaffold.

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.

Nandrolone decanoate is able to modulate proliferation and adhesion of myoblasts.

The search for a more efficient repair process of muscle injuries has become evident in clinical practice. The aim of the present study was to evaluate the effect of nandrolone decanoate (ND) on the proliferation, adhesion, and expression of myogenic regulatory factors (MRFs) in C2C12 cells.Methods. Cell proliferation and adhesion were assessed using an MTT assay. The expression of MRFs was assessed by real-time PCR.Results. ND applied at 10 or 25 µM concentration induced after 60 min an increase in adhesion, at 5 µM concentration induced after 5 days an increase in cell proliferation, and ND at 50 µM concentration led after 5 days to a decrease in cell proliferation in comparison with other groups. The steroid did not alter the expression of MRFs.Conclusions. The positive effects of ND regarding the proliferation and adhesion of C2C12 cells suggest that this steroid may have positive effects following a muscle injury.

Low-level laser therapy suppresses the oxidative stress-induced glucocorticoids resistance in U937 cells: relevance to cytokine secretion and histone deacetylase in alveolar macrophages.

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.

Modulating effect of low level-laser therapy on fibrosis in the repair process of the tibialis anterior muscle in rats.

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.

Effect of nandrolone decanoate on skeletal muscle repair.

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.

Occlusal contact in children with Temporomandibular Disorders. A pilot study.

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.

ALT-C, a disintegrin-like Cys-rich protein from Bothrops alternatus, increases skeletal myoblast viability

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.