Anti-inflammatory Effects of Compounds Extracted from Marine Sponge s: A Systematic Review.

BACKGROUND: Previous studies have experimentally validated and reported that chemical constituents of marine sponges are a source of natural anti-inflammatory substances with the biotechnological potential to develop novel drugs. AIMS: Therefore, the aim of this study was to perform a systematic review to provide an overview of the anti-inflammatory substances isolated from marine sponges with therapeutic potential. METHODS: This systematic review was performed on the Embase, PubMed, Scopus and Web of Science electronic databases. In total, 613 were found, but 340 duplicate studies were excluded, only 100 manuscripts were eligible, and 83 were included. RESULTS: The results were based on in vivo and in vitro assays, and the anti-inflammatory effects of 251 bioactive compounds extracted from marine sponges were investigated. Their anti-inflammatory activities include inhibition of pro-inflammatory mediators, such as tumor necrosis factor- α (TNF-α), interleukin-6 (IL-6), nitrite or nitric oxide (NO), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin 1ß (IL-1ß), prostaglandin E2 (PGE2), phospholipase A2 (PLA2), nuclear transcription factor-kappa B (NF-κB), leukotriene B4 (LTB4), cyclooxygenase- 1 (COX-1), and superoxide radicals. CONCLUSION: In conclusion, data suggest (approximately 98% of articles) that substances obtained from marine sponges may be promising for the development of novel anti-inflammatory drugs for the treatment of different pathological conditions.

In vitro and in vivo biological performance of hydroxyapatite from fish waste.

The aim of this study was to evaluate biocompatibility of hydroxyapatite (HAP) from fish waste using in vitro and in vivo assays. Fish samples (whitemouth croaker - Micropogonias furnieri) from the biowaste was used as HAP source. Pre-osteoblastic MC3T3-E1 cells were used in vitro study. In addition, bone defects were artificially created in rat calvaria and filled with HAP in vivo. The results demonstrated that HAP reduced cytotoxicity in pre-osteoblast cells after 3 and 6 days following HAP exposure. DNA concentration was lower in the HAP group after 6 days. Quantitative RT-PCR did not show any significant differences (p > 0.05) between groups. In vivo study revealed that bone defects filled with HAP pointed out moderate chronic inflammatory cells with slight proliferation of blood vessels after 7 and 15 days. Chronic inflammatory infiltrate was absent after 30 days of HAP exposure. There was also a decrease in the amount of biomaterial, being followed by newly formed bone tissue. All experimental groups also demonstrated strong RUNX-2 immoexpression in the granulation tissue as well as in cells in close contact with biomaterial. The number of osteoblasts inside the defect area was lower in the HAP group when compared to control group after 7 days post-implantation. Similarly, the osteoblast surface as well as the percentage of bone surface was higher in control group when compared with HAP group after 7 days post-implantation. Taken together, HAP from fish waste is a promising possibility that should be explored more carefully by tissue-engineering or biotechnology.

Bone substitutes and photobiomodulation in bone regeneration: A systematic review in animal experimental studies.

In general, bone fractures are able of healing by itself. However, in critical situations such as large bone defects, poor blood supply or even infections, the biological capacity of repair can be impaired, resulting in a delay of the consolidation process or even in non-union fractures. Thus, technologies able of improving the process of bone regeneration are of high demand. In this context, ceramic biomaterials-based bone substitutes and photobiomodulation (PBM) have been emerging as promising alternatives. Thus, the present study performed a systematic review targeting to analyze studies in the literature which investigated the effects of the association of ceramic based bone substitutes and PBM in the process of bone healing using animal models of bone defects. The search was conducted from March and April of 2019 in PubMed, Web of Science and Scopus databases. After the eligibility analyses, 16 studies were included in this review. The results showed that the most common material used was hydroxyapatite (HA) followed by Biosilicate associated with infrared PBM. Furthermore, 75% of the studies demonstrated positive effects to stimulate bone regeneration from association of ceramic biomaterials and PBM. All studies used low-level laser therapy (LLLT) device and the most studies used LLLT infrared. The evidence synthesis was moderate for all experimental studies for the variable histological analysis demonstrating the efficacy of techniques on the process of bone repair stimulation. In conclusion, this review demonstrates that the association of ceramic biomaterials and PBM presented positive effects for bone repair in experimental models of bone defects.

Bioglass/PLGA associated to photobiomodulation: effects on the healing process in an experimental model of calvarial bone defect.

Bioactive glasses (BG) are known for their ability to bond to bone tissue. However, in critical situations, even the osteogenic properties of BG may be not enough to induce bone consolidation. Thus, the enrichment of BG with polymers such as Poly (D, L-lactic-co-glycolic) acid (PLGA) and associated to photobiomodulation (PBM) may be a promising strategy to promote bone tissue healing. The aim of the present study was to investigate the in vivo performance of PLGA supplemented BG, associated to PBM therapy, using an experimental model of cranial bone defect in rats. Rats were distributed in 4 different groups (Bioglass, Bioglass/PBM, Bioglas/PLGA and BG/PLGA/PBM). After the surgical procedure to induce cranial bone defects, the pre-set samples were implanted and PBM treatment (low-level laser therapy) started (808 nm, 100 mW, 30 J/cm2). After 2 and 6 weeks, animals were euthanized, and the samples were retrieved for the histopathological, histomorphometric, picrosirius red staining and immunohistochemistry analysis. At 2 weeks post-surgery, it was observed granulation tissue and areas of newly formed bone in all experimental groups. At 6 weeks post-surgery, BG/PLGA (with or without PBM) more mature tissue around the biomaterial particles. Furthermore, there was a higher deposition of collagen for BG/PLGA in comparison with BG/PLGA/PBM, at second time-point. Histomorphometric analysis demonstrated higher values of BM.V/TV for BG compared to BG/PLGA (2 weeks post-surgery) and N.Ob/T.Ar for BG/PLGA compared to BG and BG/PBM (6 weeks post-surgery). This current study concluded that the use of BG/PLGA composites, associated or not to PBM, is a promising strategy for bone tissue engineering.

Incorporation of collagen and PLGA in bioactive glass: in vivo biological evaluation.

Bioactive glasses (BG) are known for their unique ability to bond to bone tissue. However, in critical situations, even the osteogenic properties of BG may be not sufficient to produce bone consolidation. The use of composite materials may constitute an optimized therapeutical intervention for bone stimulation. The aim of this study was to characterize BG/collagen/poly (d,l-lactic-co-glycolic) acid (BG/COL/PLGA) composites, in vitro biocompatibility and in vivo biological properties. MC3T3-E1 cells were evaluated by cell proliferation, ALP activity, cell adhesion and morphology. Qualitative histology and immunohistochemistry were performed in a calvarial bone defect model in rats. The in vitro study demonstrated, after 3 and 6 days of culture, a significant increase of proliferation was observed for BG/PLGA compared to BG/COL and BG/COL/PLGA. BG/COL/PLGA presented a higher value for ALP activity after 3 days of culture compared to BG/PLGA. For in vivo analysis, 6 weeks post-surgery, BG/PLGA showed a more mature neoformed bone tissue. As a conclusion, the in vitro and in vivo studies pointed out that BG/PLGA samples improved biological properties in calvarial bone defects, highlighting the potential of BG/PLGA composites to be used as a bone graft for bone regeneration applications.

Photobiomodulation guided healing in a sub-critical bone defect in calvarias of rats.

BACKGROUND: Photobiomodulation presents stimulatory effects on tissue metabolism, constituting a promising strategy to produce bone tissue healing. OBJECTIVE: the aim of the present study was to investigate the in vivo performance of PBM using an experimental model of cranial bone defect in rats. MATERIAL AND METHODS: rats were distributed in 2 different groups (control group and PBM group). After the surgical procedure to induce cranial bone defects, PBM treatment initiated using a 808 nm laser (100 mW, 30 J/cm2, 3 times/week). After 2 and 6 weeks, animals were euthanized and the samples were retrieved for the histopathological, histomorphometric, picrosirius red staining and immunohistochemistry analysis. RESULTS: Histology analysis demonstrated that for PBM most of the bone defect was filled with newly formed bone (with a more mature aspect when compared to CG). Histomorphomeric analysis also demonstrated a higher amount of newly formed bone deposition in the irradiated animals, 2 weeks post-surgery. Furthermore, there was a more intense deposition of collagen for PBM, with ticker fibers. Results from Runx-2 immunohistochemistry demonstrated that a higher immunostaining for CG 2 week's post-surgery and no other difference was observed for Rank-L immunostaining. CONCLUSION: This current study concluded that the use of PBM was effective in stimulating newly formed bone and collagen fiber deposition in the sub-critical bone defect, being a promising strategy for bone tissue engineering.

Low-level laser therapy modulates demyelination in mice.

There are no effective therapies for remyelination. Low-level laser therapy (LLLT) has been found advantageous in neurogenesis promotion, cell death prevention, and modulation of inflammation in central and peripheral nervous system models. The purpose of this study was to analyse LLLT effects on cuprizone-induced demyelination. Mice were randomly distributed into three groups: Control Laser (CTL), Cuprizone (CPZ), and Cuprizone Laser (CPZL). Mice from CPZ and CPZL groups were exposed to a 0.2% cuprizone oral diet for four complete weeks. Six sessions of transcranial laser irradiation were applied on three consecutive days, during the third and fourth weeks, with parameters of 36 J/cm2, 50 mW, 0.028 cm2 spot area, continuous wave, 1 J, 20 s, 1.78 W/cm2 in a single point equidistant between the eyes and ears of CTL and CPZL mice. Motor coordination was assessed by the rotarod test. Twenty-four hours after the last laser session, all animals were euthanized, and brains were extracted. Serum was obtained for lactate dehydrogenase toxicity testing. Histomorphological analyses consisted of Luxol Fast Blue staining and immunohistochemistry. The results showed that laser-treated animals presented motor performance improvement, attenuation of demyelination, increased number of oligodendrocyte precursor cells, modulated microglial and astrocytes activation, and a milder toxicity by cuprizone. Although further studies are required, it is suggested that LLLT represents a feasible therapy for demyelinating diseases.

Efficacy of intraoperatively prepared cell-based constructs for bone regeneration.

BACKGROUND: Conventional cell-based bone regeneration suffers from the major disadvantage of limited cell supply, time-consuming in vitro expansion cultures, and limited patient-friendliness related to cell isolation and multiple visits to the clinic. Here, we utilized an alternative concept using "easy access cells" that can be obtained in an intraoperative manner to prepare cell-based constructs. METHODS: We used stromal vascular fraction (SVF) from human adipose tissue and human monocytes for intraoperative preparation of bone constructs. Conventional constructs grafted with expanded human adipose tissue mesenchymal stem cells (ADMSCs) derived from the same donor were set as positive controls. Additionally, we combined both cell types either or not with monocytes. The cellular interaction of human SVF and ADMSCs with human monocytes was evaluated in vitro. The feasibility and bone-regenerative capacity of intraoperative constructs were determined histologically and histomorphometrically in a rat femoral condyle bone defect model. RESULTS: SVF displayed equal in vitro osteogenic differentiation compared to donor-matched expanded ADMSCs, which for both was significantly enhanced upon co-culture with monocytes. Moreover, SVF and ADMSCs displayed different immunoregulatory effects on monocytes/macrophages. Upon implantation in rat femoral bone defects, SVF constructs demonstrated superior bone formation compared to ADMSC constructs and cell-free controls; no effects of monocyte addition were observed. CONCLUSION: In conclusion, we here demonstrate the feasibility of intraoperative SVF construct preparation and superior bone-regenerative capacity thereof compared to donor-matched ADMSC constructs. The superiority of SVF constructs was found to be linked to the distinct differences between immunoregulatory effects of SVF and ADMSCs.

Interleukin-10 and collagen type II immunoexpression are modulated by photobiomodulation associated to aerobic and aquatic exercises in an experimental model of osteoarthritis.

The aim of this study was to compare the effects of photobiomodulation (PBM) associated with an aerobic and an aquatic exercise training on the degenerative process related to osteoarthritis (OA) in the articular cartilage in rats. Fifty male Wistar rats were randomly divided into 5 groups: OA control group (CG), OA plus aerobic training group (AET), OA plus aquatic training group (AQT), OA plus aerobic training associated with PBM group (AETL), OA plus aquatic training associated with PBM group (AQTL). The aerobic training (treadmill; 16 m/min; 50 min/day) and the aquatic training (water jumping; 50-80% of their body mass) started 4 weeks after the surgery and they were performed 3 days/week for 8 weeks. Moreover, PBM was performed after the physical exercise trainings on the left joint. Morphological characteristics and immunoexpression of IL-10, TGF-ß, and collagen type I (Col I) and II (Col II) of the articular cartilage were evaluated. The results showed that all the treated groups (exercise and PBM) presented less intense signs of degradation (measured by histopathological analysis and OARSI grade system). Additionally, aerobic and aquatic exercise training rats (associated or not with PBM) showed increased IL-10 (AET p = 0.0452; AETL p = 0.03; AQTL p = 0.0193) and Col II (AET p = 0.012; AQT p = 0.0437; AETL p = 0.0001; AQTL p = 0.0001) protein expression compared to CG. Furthermore, a statistically higher TGF-ß expression was observed in AET (p = 0.0084) and AETL (p = 0.0076) compared to CG. These results suggest that PBM associated with aerobic and aquatic exercise training were effective in mediating chondroprotective effects and maintaining the integrity of the articular tissue in the knees of OA rats.

Biomaterial Property Effects on Platelets and Macrophages: An in Vitro Study.

The purpose of this study was to evaluate the effects of surface properties of bone implants coated with hydroxyapatite (HA) and ß-tricalcium phosphate (ß-TCP) on platelets and macrophages upon implant installation and compare them to grit-blasted Ti and Thermanox used as a control. Surface properties were characterized using scanning electron microscopy, profilometry, crystallography, Fourier transform infrared spectroscopy, and coating stability. For platelets, platelet adherence and morphology were assessed. For macrophages, morphology, proliferation, and polarization were evaluated. Surface characterization showed similar roughness of ∼2.5 µm for grit-blasted Ti discs, both with and without coating. Coating stability assessment showed substantial dissolution of HA and ß-TCP coatings. Platelet adherence was significantly higher for grit-blasted Ti, Ti-HA, and Ti-ß-TCP coatings compared to that of cell culture control Thermanox. Macrophage cultures revealed a decreased proliferation on both HA and ß-TCP coated discs compared to both Thermanox and grit-blasted Ti. In contrast, secretion of pro-inflammatory cytokine TNF-α and anti-inflammatory cytokine TGF-ß were marginal for grit-blasted Ti and Thermanox, while a coating-dependent increased secretion of pro- and anti-inflammatory cytokines was observed for HA and ß-TCP coatings. The results demonstrated a significantly upregulated pro-inflammatory and anti-inflammatory cytokine secretion and marker gene expression of macrophages on HA and ß-TCP coatings. Furthermore, HA induced an earlier M1 macrophage polarization but more M2 phenotype potency than ß-TCP. In conclusion, our data showed that material surface affects the behaviors of first cell types attached to implants. Due to the demonstrated crucial roles of platelets and macrophages in bone healing and implant integration, this information will greatly aid the design of metallic implants for a higher rate of success in patients.

Putty-like bone fillers based on CaP ceramics or Biosilicate® combined with carboxymethylcellulose: Characterization, optimization, and evaluation.

Calcium phosphates and bioactive glass ceramics have been considered promising biomaterials for use in surgeries. However, their moldability should be further enhanced. We here thereby report the handling, physicochemical features, and morphological characteristics of formulations consisting of carboxymethylcellulose-glycerol and hydroxyapatite-tricalcium phosphate or Biosilicate® particles. We hypothesized that combining either material with carboxymethylcellulose-glycerol would improve handling properties, retaining their bioactivity. In addition to scanning electron microscopy, cohesion, mineralization, pH, and viscoelastic properties of the novel formulations, cell culture experiments were performed to evaluate the cytotoxicity and cell proliferation. Putty-like formulations were obtained with improved cohesion and moldability. Remarkably, mineralization in simulated body fluid of hydroxyapatite-tricalcium phosphate/carboxymethylcellulose-glycerol formulations was enhanced compared to pure hydroxyapatite-tricalcium phosphate. Cell experiments showed that all formulations were noncytotoxic and that HA-TCP60 and BGC50 extracts led to an increased cell proliferation. We conclude that combining carboxymethylcellulose-glycerol with either hydroxyapatite-tricalcium phosphate or Biosilicate® allows for the generation of moldable putties, improves handling properties, and retains the ceramic bioactivity.

Porous poly (D,L-lactide-co-glycolide) acid/biosilicate® composite scaffolds for bone tissue engineering.

This study evaluated the effects of the Biosilicate® and poly (D,L-lactic-co-glycolic) acid composites on bone repair in a tibial bone defect model in rats by means of using histological evaluation (histopathological and morphometric analysis) and gene expression analysis. Eighty male Wistar rats (12 weeks old, weighing ±300 g) were randomly divided into two groups: Biosilicate® group (BG) and Biosilicate® /PLGA group (BG/PLGA). Each group was euthanized at 3, 7, 14, and 21 days after surgery (n = 10 animals per time point). The main findings showed that the incorporation of PLGA into BG had a significant effect on the morphological structure of the material, accelerating mass loss, decreasing the pH and increasing the calcium release. Furthermore, histologic analysis revealed that the BG/PLGA showed increased material degradation, accompanied by higher bone formation compared to BG, after 21 days of implantation. In addition, qRT-PCR analysis showed that BG/PLGA induced an upregulation of the osteogenic genes related to BMP4, Runx2, ALP, and OC. These results show that the present BG/PLGA composite may be used as a bone graft for inducing bone repair. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 63-71, 2017.

Low-level laser therapy associated to a resistance training protocol on bone tissue in diabetic rats.

OBJECTIVE: The present study aimed to evaluate the in vivo response of a resistance training and low-level laser therapy (LLLT) on tibias and femurs of rats with diabetes mellitus (DM). MATERIALS AND METHODS: Forty male Wistar rats were randomly distributed into four experimental groups: control group (CG), diabetic group (DG), diabetic trained group (TG) and diabetic trained and laser irradiated group (TLG). DM was induced by streptozotocin (STZ) and after two weeks laser and resistance training started, performed for 24 sessions, during eight weeks. At the end of the experiment, animals were euthanized and tibias and femurs were removed for analysis. Histological, histomorphometrical, immunohistochemistry and mechanical analyses were performed. RESULTS: Trained groups, with or without laser irradiation, showed increased cortical area, bone density and biomechanical properties. The immunohistochemical analysis revealed that TG and TLG demonstrated an increased RUNX2 expression. RANK-L immunoexpression was similar for all experimental groups. CONCLUSION: In conclusion, it can be suggested that the resistance exercise program stimulated bone metabolism, culminating in increased cortical tibial area, bone mineral content, bone mineral density and biomechanical properties. Furthermore, the association of physical exercises and LLLT produced higher values for bone mineral content and stiffness. Consequently, these data highlight the potential of physical exercise in the management of bone loss due to DM and the possible extra osteogenic stimulus offered by lasertherapy. Further long-term studies should be carried out to provide additional information.

Low-level laser therapy associated to a resistance training protocol on bone tissue in diabetic rats

ABSTRACT Objective The present study aimed to evaluate the in vivo response of a resistance training and low-level laser therapy (LLLT) on tibias and femurs of rats with diabetes mellitus (DM). Materials and methods Forty male Wistar rats were randomly distributed into four experimental groups: control group (CG), diabetic group (DG), diabetic trained group (TG) and diabetic trained and laser irradiated group (TLG). DM was induced by streptozotocin (STZ) and after two weeks laser and resistance training started, performed for 24 sessions, during eight weeks. At the end of the experiment, animals were euthanized and tibias and femurs were removed for analysis. Histological, histomorphometrical, immunohistochemistry and mechanical analyses were performed. Results Trained groups, with or without laser irradiation, showed increased cortical area, bone density and biomechanical properties. The immunohistochemical analysis revealed that TG and TLG demonstrated an increased RUNX2 expression. RANK-L immunoexpression was similar for all experimental groups. Conclusion In conclusion, it can be suggested that the resistance exercise program stimulated bone metabolism, culminating in increased cortical tibial area, bone mineral content, bone mineral density and biomechanical properties. Furthermore, the association of physical exercises and LLLT produced higher values for bone mineral content and stiffness. Consequently, these data highlight the potential of physical exercise in the management of bone loss due to DM and the possible extra osteogenic stimulus offered by lasertherapy. Further long-term studies should be carried out to provide additional information.

Calcium phosphate fibers coated with collagen: In vivo evaluation of the effects on bone repair.

The aim of this study was to assess the characteristics of the CaP/Col composites, in powder and fiber form, via scanning electron microscopy (SEM), pH and calcium release evaluation after immersion in SBF and to evaluate the performance of these materials on the bone repair process in a tibial bone defect model. For this, four different formulations (CaP powder - CaPp, CaP powder with collagen - CaPp/Col, CaP fibers - CaPf and CaP fibers with collagen - CaPf/Col) were developed. SEM images indicated that both material forms were successfully coated with collagen and that CaPp and CaPf presented HCA precursor crystals on their surface. Although presenting different forms, FTIR analysis indicated that CaPp and CaPf maintained the characteristic peaks for this class of material. Additionally, the calcium assay study demonstrated a higher Ca uptake for CaPp compared to CaPf for up to 5 days. Furthermore, pH measurements revealed that the collagen coating prevented the acidification of the medium, leading to higher pH values for CaPp/Col and CaPf/Col. The histological analysis showed that CaPf/Col demonstrated a higher amount of newly formed bone in the region of the defect and a reduced presence of material. In summary, the results indicated that the fibrous CaP enriched with the organic part (collagen) glassy scaffold presented good degradability and bone-forming properties and also supported Runx2 and RANKL expression. These results show that the present CaP/Col fibrous composite may be used as a bone graft for inducing bone repair.

Low level laser therapy accelerates bone healing in spinal cord injured rats.

Bone loss occurs rapidly and consistently after the occurrence of a spinal cord injury (SCI), leading to a decrease in bone mineral density (BMD) and a higher risk of fractures. In this context, the stimulatory effects of low level laser therapy (LLLT) also known as photobiomodulation (PBM) have been highlighted, mainly due to its osteogenic potential. The aim of the present study was to evaluate the effects of LLLT on bone healing using an experimental model of tibial bone defect in SCI rats. Twenty-four female Wistar rats were randomly divided into 3 groups: Sham group (SG), SCI control group (SC) and SCI laser treated group (SL). Two weeks after the induction of the SCI, animals were submitted to surgery to induce a tibial bone defect. Treatment was performed 3days a week, for 2weeks, at a single point over the area of the injury, using an 808nm laser (30mW, 100J/cm(2); 0.028cm(2), 1.7W/cm², 2.8J). The results of the histological and morphometric evaluation demonstrated that the SL group showed a larger amount of newly formed bone compared to the SC group. Moreover, a significant immunoexpression of runt-related transcription factor 2 (RUNX2) was observed in the SL group. There was no statistical difference in the biomechanical evaluation. In conclusion, the results suggest that LLLT accelerated the process of bone repair in rats with complete SCI.

Investigation of the Comparative Effects of Red and Infrared Laser Therapy on Skeletal Muscle Repair in Diabetic Rats.

OBJECTIVE: The aim of this study was to evaluate the in vivo response of 2 different laser wavelengths (red and infrared) on skeletal muscle repair process in diabetic rats. DESIGN: Forty Wistar rats were randomly divided into 4 experimental groups: basal control-nondiabetic and muscle-injured animals without treatment (BC); diabetic muscle-injured without treatment (DC); diabetic muscle-injured, treated with red laser (DCR) and infrared laser (DCIR). The injured region was irradiated daily for 7 consecutive days, starting immediately after the injury using a red (660 nm) and an infrared (808 nm) laser. RESULTS: The histological results demonstrated in both treated groups (red and infrared wavelengths) a modulation of the inflammatory process and a better tissue organization located in the site of the injury. However, only infrared light significantly reduced the injured area and increased MyoD and myogenin protein expression. Moreover, both red and infrared light increased the expression of the proangiogenic vascular endothelial growth factor and reduced the cyclooxygenase 2 protein expression. CONCLUSION: These results suggest that low-level laser therapy was efficient in promoting skeletal muscle repair in diabetic rats. However, the effect of infrared wavelength was more pronounced by reducing the area of the injury and modulating the expression proteins related to the repair.

Effect of low-level laser therapy (808 nm) on skeletal muscle after endurance exercise training in rats.

BACKGROUND: Low-level laser therapy (LLLT) has been demonstrated to be effective in optimizing skeletal muscle performance in animal experiments and in clinical trials. However, little is known about the effects of LLLT on muscle recovery after endurance training. OBJECTIVE: This study evaluates the effects of low-level laser therapy (LLLT) applied after an endurance training protocol on biochemical markers and morphology of skeletal muscle in rats. METHOD: Wistar rats were divided into control group (CG), trained group (TG), and trained and laser irradiated group (TLG). The endurance training was performed on a treadmill, 1 h/day, 5 days/wk, for 8 wk at 60% of the maximal speed reached during the maximal effort test (Tmax) and laser irradiation was applied after training. RESULTS: Both trained groups showed significant increase in speed compared to the CG. The TLG demonstrated a significantly reduced lactate level, increased tibialis anterior (TA) fiber cross-section area, and decreased TA fiber density. Myogenin expression was higher in soleus and TA muscles in both trained groups. In addition, LLLT produced myogenin downregulation in the TA muscle of trained animals. CONCLUSION: These results suggest that LLLT could be an effective therapeutic approach for stimulating recovery during an endurance exercise protocol.

Effect of low-level laser therapy (808 nm) on skeletal muscle after endurance exercise training in rats

BACKGROUND: Low-level laser therapy (LLLT) has been demonstrated to be effective in optimizing skeletal muscle performance in animal experiments and in clinical trials. However, little is known about the effects of LLLT on muscle recovery after endurance training. OBJECTIVE: This study evaluates the effects of low-level laser therapy (LLLT) applied after an endurance training protocol on biochemical markers and morphology of skeletal muscle in rats. METHOD: Wistar rats were divided into control group (CG), trained group (TG), and trained and laser irradiated group (TLG). The endurance training was performed on a treadmill, 1 h/day, 5 days/wk, for 8 wk at 60% of the maximal speed reached during the maximal effort test (Tmax) and laser irradiation was applied after training. RESULTS: Both trained groups showed significant increase in speed compared to the CG. The TLG demonstrated a significantly reduced lactate level, increased tibialis anterior (TA) fiber cross-section area, and decreased TA fiber density. Myogenin expression was higher in soleus and TA muscles in both trained groups. In addition, LLLT produced myogenin downregulation in the TA muscle of trained animals. CONCLUSION: These results suggest that LLLT could be an effective therapeutic approach for stimulating recovery during an endurance exercise protocol.

Photobiomodulation and bone healing in diabetic rats: evaluation of bone response using a tibial defect experimental model.

Diabetes mellitus (DM) leads to a delay in bone healing. Thus, some therapeutic approaches have been used to accelerate the process of bone repair such as photobiomodulation (PBM). Therefore, the present study aimed to evaluate the effects of PBM, in different fluences, in bone repair in an experimental model of tibial bone defects in diabetic rats. Sixty-four Wistar rats were submitted to a surgical procedure to perform bone defect and distributed in four groups: diabetic control group (DCG), diabetic laser group 30 J/cm(2) (L30), diabetic laser group 60 J/cm(2) (L60), and diabetic laser group 120 J/cm(2) (L120). A 808 nm Ga-Al-As (DMC Equipment, São Carlos, SP, Brazil) laser, 100 mW; 0.028 cm(2); 3.57 W/cm(2); 30, 60, and 120 J/cm(2); 0.84, 1.68, and 3.36 J; 8, 16, and 33 s was used. Animals were euthanized 15 and 30 days after the surgery. Histological, morphometric, immunohistochemistry, and biomechanical analyses were performed. In the histological and morphometric evaluation, all laser-treated groups showed a better histological pattern and a higher amount of newly formed bone compared to DCG. An intense RUNX2 immunoexpression was observed in the laser-treated groups, 15 days after the surgery. Receptor activator of nuclear factor κ-ß ligand (RANK-L) immunohistochemistry analysis showed a significant decrease in the immunoreactivity for L30 and L120, 30 days after surgery. There was no statistical difference in the biomechanical analysis among the groups. In conclusion, PBM, in all fluences used, showed an osteogenic potential in bone healing of diabetic rats.