Evaluation of the comparative effects of infrared and red laser photobiomodulation therapy on skeletal muscle atrophy in an immobilization model in rats

Introduction: Skeletal muscle atrophy leads to a reduction in muscle strength, functionality, and the quality of life of individuals. Objective: To explore the effects of two different wavelengths (red and infrared) of laser PBMT on muscle atrophy and its active ingredients on skeletal muscle atrophy using an in vivo model of muscle atrophy. Methods: Thirty-two Wistar rats were randomly divided into four experimental groups: control (CG) animals were not immobilized and did not receive any type of treatment; immobilized animals with no treatment (ImC); immobilized animals submitted to red laser with wavelength of 660 nm (ImR) and near-infrared laser with wavelength of 808 nm (ImIR) treatments. The treatments were applied daily, at 2 points in the right gastrocnemius muscle (cranial and caudal), through the punctual contact technique, for 9 sessions, with the first application immediately after removing the cast. Results: The histological results demonstrated that in both treated groups (red and infrared wavelengths) a reduction of the inflammatory infiltrate and less connective tissue thickening when compared to the ImC. However, only infrared light was observed regenerating muscle fibers and an increase in the number of oxidative fibers (type I). Conclusion: These results suggest that red and infrared wavelength laser PBMT were able to promote changes in the morphology of the gastrocnemius muscle submitted to atrophy in an experimental immobilization model, reducing the inflammatory infiltrate and the formation of intramuscular connective tissue. However, infrared laser PBMT promoted more evident positive effects by increasing regenerating muscle fibers and the number of oxidative fibers.

Red LED light therapy associated with epidermal growth factor on wound repair process in rats.

Epidermal growth factor (EGF) and light-emitting diode (LED) are currently deployed as promissory treatments for skin repair; however, the mechanisms of their association are not yet evidenced. Thus, the present study aimed to evaluate the effects of combined treatment with EGF and red LED on the wound healing processes in rats. Adult Wistar rats were randomized in control group (CG) wounds without treatment; wounds submitted to EGF treatment (EGF); wounds submitted to LED treatment (LED); wounds submitted to EGF associated with LED treatments (EGF/LED). Treatments were performed immediately after the surgical procedure and each 24 h, totaling 8 sessions. Moreover, LED was applied before EGF treatment at a single point in the center of the wound. Morphological characteristics and the immunoexpression of COX-2, VEGF, and TGF-ß were measured. The results demonstrated that EGF/LED group presented a higher wound healing index. Additionally, all experimental groups presented similar findings in the histological evaluation, the degree of inflammation, and the area of dermis-like tissue. However, for EGF-treated animals (with or without LED), neoepithelial length was higher. Furthermore, all the treated groups decreased COX-2 and increased VEGF immunoexpression, and only EGF/LED group enhanced the TGF-ß protein expression when compared to the untreated group. This research shows that EGF and LED modulate inflammatory process and increase the vascularity. In addition, treatment of EGF associated with LED promoted a more evident positive effect for increasing TGF-ß expression and may be promising resources in the clinical treatment of cutaneous wounds.

Duchenne muscular dystrophy progression induced by downhill running is accompanied by increased endomysial fibrosis and oxidative damage DNA in muscle of mdx mice.

Duchenne muscular dystrophy (DMD) is characterized by progressive muscle necrosis. One of the major challenges for prescribing physical rehabilitation exercises for DMD patients is associated with the lack of a thorough knowledge of dystrophic muscle responsiveness to exercise. This study aims to understand the relationship between myogenic regulation, inflammation and oxidative stress parameters, and disease progression induced by downhill running in the skeletal muscle of an experimental model of DMD. Six-month-old C57BL/10 and C57BL/10-DMDmdx male mice were distributed into three groups: Control (C), mdx, and mdx + Exercise (mdx + Ex). Animals were trained in a downhill running protocol for seven weeks. The gastrocnemius muscle was subjected to histopathology, muscle regeneration (myoD and myogenin), inflammation (COX-2), oxidative stress (8-OHdG) immunohistochemistry markers, and gene expression (qPCR) of NF-kB and NADP(H)Oxidase 2 (NOX-2) analysis. In the mdx + Ex group, the gastrocnemius muscle showed a higher incidence of endomysial fibrosis and a lower myonecrosis percentage area. Immunohistochemical analysis revealed decreased myogenin immunoexpression in the mdx group, as well as accentuated immunoexpression of nuclear 8-OHdG in both mdx groups and increase in cytoplasmic 8-OHdG only in the mdx + Ex. COX-2 immunoexpression was related to areas of regeneration process and inflammatory infiltrate in the mdx group, while associated with areas of muscle fibrosis in the mdx + Ex. Moreover, the NF-kB gene expression was not influenced by exercise; however, a NAD(P)HOxidase 2 increase was observed. Oxidative stress and oxidative DNA damage play a significant role in the DMD phenotype progression induced by exercise, compromising cellular patterns resulting in increased endomysial fibrosis.

Cytotoxicity, Inflammatory Activity, and Angiogenesis Are Induced by Different Silicone Implants.

BACKGROUND/AIM: The aim of this study was to investigate cytotoxicity, inflammatory response, and angiogenesis induced by silicone gel breast implants with different textured surfaces in vitro and in vivo. MATERIALS AND METHODS: In the in vitro study, murine fibroblast cells (L929) were cultured for 1, 3, and 5 days with silicone membranes of three different textures: nanotextured, microtextured, and silicone foam. In the in vivo study, a total of 30 male rats (Rattus, norvegicus, albinos, Wistar) were distributed into three groups (10 animals per group), with 2 implants in each rat: nanotextured silicone gel breast implants group, microtextured silicone gel breast implants group, and silicone gel breast foam implants group. RESULTS: The Alamar Blue assay detected higher viability of cells cultured in the presence of nanotextured silicone surface for 1 and 3 days. The MTT assay showed higher cytotoxicity of silicone foam after 1 and 3 days of exposure. Nanotextured silicone breast implants induced a more prolonged inflammatory response, denoting a delay in the healing process and subsequent organization of the fibrous capsule as depicted by the collagen fiber types found. VEGF expression did not differ between experimental groups. CONCLUSION: Gel foam breast implants are more biocompatible when compared to micro- or nano-textured silicone breast implants.

Effects of photobiomodulation on glucose homeostasis and morphometric parameters in pancreatic islets of diabetic mice.

High-fat diets lead to accumulation of body fat that is associated with the onset of insulin resistance and type II diabetes mellitus. On the other hand, photobiomodulation (PBM) is an electrophysical resource that interacts with cells, stimulating mitochondrial respiration, increasing ATP production, reducing key inflammatory mediators, inhibiting apoptosis, and stimulating angiogenesis. However, little is known about its therapeutic effectiveness on the development of diabetes in diet-induced obese mice. Thus, our aim was to evaluate the effect of PBM applied single point over the pancreas area on glucose homeostasis, insulin expression, and pancreatic morphometric parameters of mice submitted to high-fat diet for 12 weeks. Male mice C57BL6/J were divided into three groups: control group (C), diabetic group (D), and diabetic + PBM (D + PBM). The treatment with PBM started at 9th week and ended in the 12th week, applied 3 × /week. Body mass, fast blood glucose, and glucose and insulin tolerance were evaluated. Immunohistochemistry to detect insulin expression and pancreatic morphometry were also performed. At the end of 12th week, both groups submitted to high-fat diet showed an increase in body mass, adiposity, disturbances on glucose homeostasis, and high insulin expression when compared to the control group. However, mice treated with PBM had more discrete impairments on glucose homeostasis during the glucose tolerance test when compared to untreated D animals. Despite modest, the results were positive and encourage future investigations to explore different doses and duration of PBM to better elucidate its role in obesity-associated type 2 diabetes development.

Articular cartilage degeneration and bone adaptation due to lack of dystrophin in mice.

INTRODUCTION: Duchenne muscular dystrophy is caused by the absence of dystrophin. This study aimed to investigate femoral morphological characteristics of lack of dystrophin in MDX mice, considering that this model, different from DMD patient, is not influenced by corticosteroids administration and limited ambulation. MATERIALS AND METHODS: Proximal femur of male 16-week-old Control and MDX mice were submitted to histological, morphometric (volume density of articular cartilage, compact bone, trabecular bone and bone marrow; articular cartilage layers area; articular cartilage cell area), and immunohistochemistry analysis for RUNX-2, RANK-L, MMP-2, MMP-9, Caspase-3 and KI-67. RESULTS: MDX showed loss of linearity of articular cartilage with subchondral bone transition and elevation of this subchondral bone to the articular surface when compared with control. In addition, MDX presented morphological difference in the pantographic network of collagen fibers. Volume density of trabecular bone tissue was higher in the MDX than Control, but volume density of articular cartilage was lower in MDX (p < 0.05). The articular cartilage layers and chondrocytes area were significantly smaller in MDX than Control. These results associated to MMPs and osteogenic markers of proximal femur revealed an adaptation process as a consequence of lack of dystrophin. CONCLUSIONS: The morphological changes observed in the bone tissue of the MDX may be not only secondary to muscle weakness or chronic use of corticosteroids but also our results indicate connections between decrease of cartilage thickness, collagen network alteration and consequent subchondral changes that may lead to articular cartilage degeneration and bone adaptation mechanism in MDX mice.

Sleep Deprivation Interferes with JAK/STAT Signaling Pathway and Myogenesis in the Masseter Muscle of Rats.

OBJECTIVES: The aim of the study was to study the Janus kinase/tyrosine kinase-activated transduction factor (JAK/STAT) signaling pathway and myogenesis on the masseter muscle after sleep deprivation and to investigate the role of stress in this scenario. SUBJECTS AND METHODS: A total of 18 male Wistar rats were divided into the following groups: control (n = 6): animals were not submitted to any procedures, and paradoxical sleep deprivation and vehicle (PSD + V; n = 6): animals were subjected to PSD for 96 h and (PSD + MET; n = 6): animals were subjected to PSD for 96 h with administration of metyrapone. Paradoxical sleep deprivation was performed by the modified multiple platforms method. Histopathological analysis, histomorphometry, and immunohistochemistry were performed. RESULTS: The results showed the presence of inflammatory infiltrate in the PSD + V and PSD + MET groups and atrophy. Histomorphometry showed that the cellular profile area decreased, while cellular density increased in both experimental groups. Expression of p-STAT 3, MyoD, and MyoG increased in the PSD + V group, while the PSD + MET group showed increased expression of IL-6 and p-STAT 3. CONCLUSION: Our results suggest that sleep deprivation induces an inflammatory response and atrophy in the masseter muscle of rats.

Insulin Modulates Myogenesis and Muscle Atrophy Resulting From Skin Scald Burn in Young Male Rats.

BACKGROUND: Burn injuries (BIs) due to scalding are one of the most common accidents among children. BIs greater than 40% of total body surface area are considered extensive and result in local and systemic response. We sought to assess morphological and myogenic mechanisms through both short- and long-term intensive insulin therapies that affect the skeletal muscle after extensive skin BI in young rats. MATERIALS AND METHODS: Wistar rats aged 21 d were distributed into four groups: control (C), control with insulin (C + I), scald burn injury (SI), and SI with insulin (SI + I). The SI groups were submitted to a 45% total body surface area burn, and the C + I and SI + I groups received insulin (5 UI/Kg/d) for 4 or 14 d. Glucose tolerance and the homeostatic model assessment of insulin resistance index were determined. Gastrocnemius muscles were analyzed for histopathological, morphometric, and immunohistochemical myogenic parameters (Pax7, MyoD, and MyoG); in addition, the expression of genes related to muscle atrophy (MuRF1 and MAFbx) and its regulation (IGF-1) were also assessed. RESULTS: Short-term treatment with insulin favored muscle regeneration by primary myogenesis and decreased muscle atrophy in animals with BIs, whereas the long-term treatment modulated myogenesis by increasing the MyoD protein. Both treatments improved histopathological parameters and secondary myogenesis by increasing the MyoG protein. CONCLUSIONS: Treatment with insulin benefits myogenic parameters during regeneration and modulates MuRF1, an important mediator of muscle atrophy.

Extensive burn injury causes bone collagen network alteration and growth delay related to RANK-L immunoexpression change.

PURPOSE: Extensive burn injury mainly affects children, and hypermetabolic state can lead to growth delay. This study aimed to investigate bone histopathological and morphometric aspects, collagen fibers network and the immunoexpression of biological markers related to bone development in a young experimental model for extensive burn. MATERIALS AND METHODS: A total of 28 male Wistar rats were distributed into Control (C) and subjected to scald burn injury (SBI) groups. Sham or injured animals were euthanized 4 or 14 days post-lesion and proximal epiphyses of the femur were submitted to histological, morphometric (thickness epiphyseal plate), and RUNX-2 and receptor activator of nuclear factor kappa- ß ligand (RANK-L) immunoexpression methods. RESULTS: Histopathological femoral findings showed delayed appearance of the secondary ossification center in SBI, 14 days post-injury. Collagen fibers 4 days after injury were observed in articular cartilage as a pantographic network with a transversally oriented lozenge-shaped mesh, but this network was thinner in SBI. Fourteen days after the injury, the pantographic network of collagen presented square-shaped mesh in C, but this aspect was changed to a wider mesh in SBI. Morphometric analysis of epiphyseal plate revealed that the SBI group had less thickness than the respective controls (p<0.05). RUNX-2 showed no difference between groups, but RANK-L score was higher in all SBI groups. CONCLUSIONS: Extensive burn injury causes delayed bone growth and morphological changes. Alterations in collagen network and enhancement in immunoreactivity of RANK-L result in increased osteoclastogenesis.

Presence of metalloproteinases 2 and 9 and 8-OHdG in the fibrotic process in skeletal muscle of Mdx mice.

Inflammation and oxidative stress occurs in muscle of Duchenne muscular dystrophy (DMD). The relationship between a panel of biomarkers and the DMD outcome is necessary to indicate of disease progression and response to rehabilitation programs. The aim was to analyze the connective tissue of muscle of Mdx mice and immunoexpression of MMP-2, MMP-9, and 8-OHdG, which signalizes oxidative stress related to DNA damage. Biceps brachii of male C57BL/10 and C57BL/10-Dmdmdx mice was submitted to Hematoxylin-Eosin, Sirius red and immunohistochemistry (MMP-2, MMP-9 and 8-OHdG) analysis. Mdx showed focal lesions with intense inflammation and fibrosis related to immunoexpression of MMP-2 and MMP-9, proving the hypothesis that these MMPs are linked to muscular tissue degeneration, which can be regenerated by their inhibition, improving the treatment of DMD carriers. Histopathological findings related to centralized nuclei increase were related to higher 8-OHdG immunomarked nuclei in Mdx, which signalizes oxidative stress associated with DNA damage provoked by DMD. Such result shows that the evaluation of 8-OHdG during the evolution of the disease could be a method to evaluate DMD disease progression.

Paradoxical sleep deprivation induces differential biological response in rat masticatory muscles: Inflammation, autophagy and myogenesis.

BACKGROUND: The aim of this study was to evaluate whether sleep deprivation (SD) induces inflammation, autophagy and myogenesis in the following masticatory muscles: masseter and temporal. METHODS: In this study, 18 animals were randomly distributed into three groups: control group (CTL, n = 6), SD for 96 hours (SD96, n = 6), and SD for 96 hours and more 96 hours of sleep recovery (SD96 + R, n = 6). RESULTS: In the histopathological analysis, SD 96 was able to induce inflammation in masseter and temporal. Nevertheless, the lack of inflammatory process was evidenced to the masseter in the group SD96 + R. Upregulation of TNF-alpha production was detected in the SD96 group, while SD96 + R decreased TNF immunoexpression for both skeletal muscles evaluated. MyoD and myogenin increased in rats submitted to SD96. By contrast, the levels of MyoD decreased in the group SD96 + R. Myogenin pointed out high immunoexpression in SD96 + R groups. In temporal, pAkt decreased in animals submitted to SD96, but it increased in the group SD96 + R. The levels of LC3 protein increased in both skeletal muscles studied, and masseter decreased LC3 protein expression in the SD96 + R. CONCLUSION: In summary, our results demonstrate that SD is able to induce inflammation, atrophy and myogenesis in rat masticatory muscles, being more intense in temporal when compared to masseter.

Evaluation of Collagen Fibers, MMP2, MMP9, 8-OHdG and Apoptosis in the Aorta of Ovariectomized LDL Knockout Mice Submitted to Aerobic Exercise / Avaliação de Fibras de Colágeno, MMP2, MMP9, 8-OH-Dg e Apoptose na Aorta de Ratas LDL Nocaute Ovariectomizadas Submetidas a Exercício Aeróbico

Abstract Background: In menopause, there is greater cellular exposure to oxidative stress, related to the decreased antioxidative effects of estrogen. These metabolic changes favor the progression of cardiovascular diseases, such as atherosclerosis. Abnormal function of the aorta - the most important artery - is associated with many cardiovascular diseases. Collagen, especially types I and III, is one of the most important aortic wall components and it can be affected by many factors, including menopause. The 8-OHdG is one of the main markers of DNA oxidative damage induced by reactive oxygen species (ROS). Objective: We aimed to investigate effects of moderate aerobic training on the ascending aorta of LDL-knockout (LDL-KO) and ovariectomized female mice. Methods: A total of 15 C57BL/6 mice and 15 LDL-KO mice were divided into experimental groups. The thickness and volume density of types I and III collagen fibers were performed by morphoquantitative analysis, whereas the MMP-2 and MMP-9 and 8-OHdG were detected by immunohistochemistry and apoptosis was detected by the TUNEL assay. The significance level for all tests was p < 0.05. Results: Exercise causes an increase in the thickness of the aorta in LDL-KO groups, particularly accentuated in the ovariectomized groups. The type I collagen fibers showed an increase in volume density influenced by training in both Control groups and in the LDL-KO group. Type III collagen density decreased in both groups. The MMP-2 showed moderade immunostaining in the tunica media in LDL-KO groups, which did not occur in the control groups and the MMP-9 stained irregularly in all tissues. The marker 8-OhdG was stronger in the exercise training groups. Additionally, the ovariectomy, the exercise training and the LDL-KO treatments increased apoptosis. Conclusion: These results suggest that moderate-intensity aerobic exercise in ovariectomized mice associated to an increase in LDL rate possibly increases oxidative stress and apoptosis induction.

Resumo Fundamento: Na menopausa, há maior exposição celular ao estresse oxidativo, relacionada à diminuição dos efeitos antioxidantes do estrogênio. Essas alterações metabólicas favorecem a progressão das doenças cardiovasculares, como a aterosclerose. A função anormal da aorta - a artéria mais importante - está associada a muitas doenças cardiovasculares. O colágeno, especialmente os tipos I e III, é um dos mais importantes componentes da parede da aorta e pode ser afetado por muitos fatores, incluindo a menopausa. Por sua vez, 8-OHdG é um dos principais marcadores de danos oxidativos do DNA induzidos por espécies reativas de oxigênio (EROS). Objetivo: Investigar os efeitos do treinamento aeróbico moderado na aorta ascendente de camundongos fêmeas, nocaute para LDL (LDL-KO) e ovariectomizadas. Métodos: Um total de 15 animais C57BL/6 e 15 animais LDL-KO foram divididos em grupos experimentais. A espessura e a densidade de volume das fibras de colágeno tipos I e III foram realizadas por análise morfoquantitativa; MMP-2 e MMP-9 e 8-OHdG foram detectadas por imunohistoquímica; e a apoptose foi detectada pelo ensaio TUNEL. O nível de significância adotado para todos os testes realizados foi p < 0,05. Resultados: o exercício causa aumento da espessura da aorta em grupos LDL-KO, particularmente acentuada em grupos ovariectomizados. As fibras de colágeno de tipo I mostraram aumento da densidade de volume influenciado pelo treinamento em animais controle e LDL-KO. A densidade do colágeno tipo III diminuiu em ambos os grupos. A MMP-2 mostrou imunomarcação moderada na túnica média em animais LDL-KO; em grupos controle, a MMP-9 marcou irregularmente em todos os tecidos. O marcador 8-OHdG foi mais forte nos grupos de treinamento de exercícios. Além disso, a ovariectomia, o treinamento físico e os tratamentos de LDL-KO aumentaram a apoptose. Conclusão: Esses resultados sugerem que exercícios aeróbicos de intensidade moderada em camundongos ovariectomizados associados ao aumento da taxa de LDL, possivelmente, aumentam o estresse oxidativo e a indução da apoptose.

Short time insulin treatment post burn improves elastic-collagen rearrangement and reepithelization.

Extensive burn may cause acute resistance to insulin, which accentuates hypermetabolism, impairs glucose metabolism, immune dysfunction and risks of sepsis. To minimize these effects, insulin is used as a treatment. The purpose was to analyze the collagen-elastic arrangement effects of insulin on the burned skin. Wistar rats were assigned in groups: control (C); control with insulin (C + I); scald burn injury (SBI); and SBI with insulin (SBI+ I). SBI were submitted to 45% total body surface area burn and the insulin-treated groups received insulin (5 UI/Kg/day) for 4 or 14 days (d). Insulin levels, glucose tolerance test and HOMA index were determined. The skin sections were analyzed for histophatological and morphoquantitative data. Histopathological findings showed increased reepithelization of SBI+ I and formation of a new muscle layer after 14 days. In the collagen-elastic arrangement, insulin for 4 days increased the volume fraction (Vv) of thin collagen and elastic fibers. After 14 days, independently of injury, insulin decreased the elastic fibers. Insulin was able to reverse damages in the collagen-elastic rearrangement and stimulate reepithelization after 4 days. Untreated scald-burned animals showed higher Vv of thick collagen after 4 days, while those treated had a higher Vv of thin collagen. The Vv of elastic fibers was increased in SBI+ I for 4 days. In conclusion, insulin treatment was able to stimulate reepithelization. It also reversed the damages to the collagen-elastic arrangement in the scald-burned group, improving the organization of thin collagen and increasing the Vv of elastic fibers in the injured group treated with insulin for a short time, that is, for 4 days.

Evaluation of Collagen Fibers, MMP2, MMP9, 8-OHdG and Apoptosis in the Aorta of Ovariectomized LDL Knockout Mice Submitted to Aerobic Exercise.

BACKGROUND: In menopause, there is greater cellular exposure to oxidative stress, related to the decreased antioxidative effects of estrogen. These metabolic changes favor the progression of cardiovascular diseases, such as atherosclerosis. Abnormal function of the aorta - the most important artery - is associated with many cardiovascular diseases. Collagen, especially types I and III, is one of the most important aortic wall components and it can be affected by many factors, including menopause. The 8-OHdG is one of the main markers of DNA oxidative damage induced by reactive oxygen species (ROS). OBJECTIVE: We aimed to investigate effects of moderate aerobic training on the ascending aorta of LDL-knockout (LDL-KO) and ovariectomized female mice. METHODS: A total of 15 C57BL/6 mice and 15 LDL-KO mice were divided into experimental groups. The thickness and volume density of types I and III collagen fibers were performed by morphoquantitative analysis, whereas the MMP-2 and MMP-9 and 8-OHdG were detected by immunohistochemistry and apoptosis was detected by the TUNEL assay. The significance level for all tests was p < 0.05. RESULTS: Exercise causes an increase in the thickness of the aorta in LDL-KO groups, particularly accentuated in the ovariectomized groups. The type I collagen fibers showed an increase in volume density influenced by training in both Control groups and in the LDL-KO group. Type III collagen density decreased in both groups. The MMP-2 showed moderade immunostaining in the tunica media in LDL-KO groups, which did not occur in the control groups and the MMP-9 stained irregularly in all tissues. The marker 8-OhdG was stronger in the exercise training groups. Additionally, the ovariectomy, the exercise training and the LDL-KO treatments increased apoptosis. CONCLUSION: These results suggest that moderate-intensity aerobic exercise in ovariectomized mice associated to an increase in LDL rate possibly increases oxidative stress and apoptosis induction.

Importância clínica do músculo esternal e suas variações anatômicas: uma revisão sistemática da literatura / Clinical importance of sternalis muscle and anatomical variations: a systematic review of literature

A presença do músculo esternal é uma variação anatômica que está situada anteriormente ao osso esterno e suas estruturas adjacentes e não tem função totalmente definida. Há na literatura mais relatos de estudos anatômicos sobre o músculo esternal do que sobre as implicações clínicas da sua presença. O objetivo deste estudo foi analisar as descrições existentes das variações anatômicas do músculo esternal, compreendendo, assim, a importância clínica desse conhecimento. Foram avaliados artigos nas línguas portuguesa e inglesa, indexados nas bases de dados PubMed e SciELO, publicados entre 1867 e 2016. Buscou-se verificar os tipos de variações anatômicas do músculo esternal descritas, suas origens e inserções, inervação e irrigação sanguínea. Em seguida, foi relatada a importância clínica do conhecimento dessa variação. O músculo esternal apresenta diversas dimensões e inserções, o que dificulta a determinação de sua função. Devido à localização paraesternal, em exames de imagem o referido músculo pode ser visto como uma nodulação anormal na região da mama e ser confundido com um tumor. O reconhecimento dessa variação antes de procedimentos cirúrgicos na parede torácica evita possíveis complicações e possibilita o uso do tecido como retalho muscular em cirurgias reconstrutivas da mama; também pode ser usado na melhora de resultados estéticos em mamoplastia de aumento ou fornecer cobertura extra para próteses. O conhecimento sobre essa variação anatômica é bastante relevante, pois a percepção da existência do músculo esternal e de suas variações relaciona-se a importantes implicações clínicas em cirurgias de mama e tórax.

The presence of sternal muscle is an anatomical variation, located above the sternum and adjacent structures, and its function is not fully defined. In the literature, there are more reports of anatomical studies of the sternal muscle than clinical implications of its presence. The objective of this study was to analyze descriptions about anatomical variations of the sternal muscle and understand the clinical importance of this knowledge. Articles in Portuguese and English, indexed in the databases PubMed and SciELO, from 1867 to 2016, were evaluated. The types of anatomical variants of sternal muscle its origins and insertions, innervation and blood supply were observed. After that, was brought the clinical importance of knowledge of this variation. The sternal muscle has several dimensions and inserts, making difficult to determine its function. Due to its parasternal location in imaging studies it may be seen as an abnormal bulge in the breast region and confused with a tumor. The discovery of this variation before thoracic surgical procedures avoids possible complications,enabling its use as a muscle flap in reconstructive surgery after mastectomy or improving the aesthetic result of breast augmentation providing extra covering for the prosthesis. The knowledge about this anatomical variation is quite relevant, because the perception of the existence of the sternum muscle and its variations is related to important clinical implications in breast and chest surgeries.

Protein Malnutrition Pre- and Postnatal and Nutritional Rehabilitation Modulates the Morphology of Muscle Fibers in Wistar Rats.

This study investigated the effects of pre- and postnatal conditions of protein deficiency followed to nutritional rehabilitation in the morphology of skeletal muscle. Twelve Wistar male rats were distributed in two groups: nourished (N), with normal protein diet and undernourished (U), with low protein diet. The respective diet was maintained until animals completed 21 days of life. After that, part of group U (n = 4) received normal protein diet, forming a third group, renourished group (R). Forty-two-day-old animals were euthanized and we performed histopathological and morphometric analysis of the soleus muscle. Analysis stained in hematoxylin and eosin (H&E) of the group N revealed polygonal and equidistant muscle fibers, with normal distribution in muscle fascicles. However, D group had rounded and disorganized fibers with different distances between them in muscle fascicles. R group presented muscle fibers with several formats, polygonal and rounded, and some muscle fascicles starting the reorganization process. In N group, analysis of the connective tissue showed predominance of type I collagen and a lower amount collagen type III, both well organized. Whereas U group had a predominance of disorganized type III collagen, in R group, there was return of type I collagen, but partially organized. Muscle fiber area of U (163.18 ± 52.55 µm2) and R (381.79 ± 26.62 µm2) groups was smaller than N (1229.2 µm2 ± 61.12 µm2). Muscle fibers density of groups U (3369 ± 1226 fibers/mm2) and R (1979 ± 28 fibers/mm2) was larger than N (830 ± 113 fibers/mm2). The nutritional rehabilitation in the present study showed an attempt of reorganization of the muscle tissue.

Burn injury induces histopathological changes and cell proliferation in liver of rats.

AIM: To investigate effects of severe burn injury (BI) in rat liver through the histopathological and inflammatory markers analysis. METHODS: Forty-two male Wistar rats were distributed into two groups, control (C) and subjected to scald BI (SBI). The animals were euthanized one, four and 14 d post sham or 45% of the total body surface BI. Liver fragments were submitted to histopathological, morphoquantitative (hepatocyte area and cell density), ciclooxigenase-2 (COX-2) immunoexpression, and gene expression [real-time polymerase chain reaction for tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS) and caspase-3] methods. RESULTS: Histopathological findings showed inflammatory process in all periods investigated and hepatocyte degeneration added to increased amount of connective tissue 14 d post injury. Hepatocyte area, the density of binucleated hepatocytes and density of sinusoidal cells of SBI groups were increased when compared with control. COX-2 immunoexpression was stronger in SBI groups. No differences were found in TNF-α, iNOS and caspase-3 gene expression. CONCLUSION: BI induces histopathological changes, upregulation of COX-2 immunoexpression, and cell proliferation in liver of rats.

Burn injury induces skeletal muscle degeneration, inflammatory host response, and oxidative stress in wistar rats.

Burn injuries (BIs) result in both local and systemic responses distant from the site of thermal injury, such as skeletal muscle. The purpose of this study was to investigate the expression of cyclooxygenase-2 (COX-2) and hydroxy-2'-deoxyguanosine (8-OHdG) as a result of inflammation and reactive oxygen species production, respectively. A total of 16 male rats were distributed into two groups: control (C) and submitted to BI. The medial part of gastrocnemius muscle formed the specimens, which were stained with hematoxylin and eosin and were evaluated. COX-2 and 8-OHdG expressions were assessed by immunohistochemistry, and cell profile area and density of muscle fibers (number of fibers per square millimeter) were evaluated by morphometric methods. The results revealed inflammatory infiltrate associated with COX-2 immunoexpression in BI-gastrocnemius muscle. Furthermore, a substantial decrease in the muscle cell profile area of BI group was noticed when compared with the control group, whereas the density of muscle fibers was higher in the BI group. 8-OHdG expression in numerous skeletal muscle nuclei was detected in the BI group. In conclusion, the BI group is able to induce skeletal muscle degeneration as a result of systemic host response closely related to reactive oxygen species production and inflammatory process.

Low-level laser therapy modulates musculoskeletal loss in a skin burn model in rats.

PURPOSE: To investigate the effectiveness of low-level laser therapy (LLLT) on gastrocnemius muscle morphology and Myod immunoexpression in a model of dorsal burn in rats. METHODS: Sixteen male Wistar rats were distributed into two groups: control group (CG): rats submitted to scald burn injury without treatment and laser treated group (LG): rats submitted to scald burn injury and treated with laser therapy. Fourteen days post-surgery, gastrocnemius muscle was evaluated being the specimens stained with HE and morphometric data was evaluated. MyoD expression was assessed by immunohistochemistry. RESULTS: The results showed that laser treated animals presented more organized tissue morphology compared to the non-treated animals, with a higher number of nucleus in the fibers. Also, the cross sectional area of the fibers and the MyoD immunoexpression in the laser treated groups was higher. CONCLUSION: Low-level laser therapy had positive effects on gastrocnemius muscle, improving tissue muscle morphology, increasing cross sectional area and MyoD immunoexpression.

Low-level laser therapy modulates musculoskeletal loss in a skin burn model in rats

PURPOSE: To investigate the effectiveness of low-level laser therapy (LLLT) on gastrocnemius muscle morphology and Myod imunoexpression in a model of dorsal burn in rats. METHODS: Sixteen male Wistar rats were distributed into two groups: control group (CG): rats submitted to scald burn injury without treatment and laser treated group (LG): rats submitted to scald burn injury and treated with laser therapy. Fourteen days post-surgery, gastrocnemius muscle was evaluated being the specimens stained with HE and morphometric data was evaluated. MyoD expression was assessed by immunohistochemistry. RESULTS: The results showed that laser treated animals presented more organized tissue morphology compared to the non-treated animals, with a higher number of nucleus in the fibers. Also, the cross sectional area of the fibers and the MyoD immunoexpression in the laser treated groups was higher. CONCLUSION: Low-level laser therapy had positive effects on gastrocnemius muscle, improving tissue muscle morphology, increasing cross sectional area and MyoD immunoexpression. .