Smoking Intensity Increases Diaphragm Muscle Injury: A Clinicopathologic Study.

BACKGROUND: Studying the effects of smoking intensity is important to evaluate the risk of tobacco use on a range of illnesses, such as as sarcopenia among the elderly. Thus, this study aimed to analyze the effects of pack-years of cigarette smoking on the diaphragm muscle (DIAm) histopathology of postmortem samples. METHODS: Subjects were divided into three groups: never-smoker (n = 46); less than 30 pack-years of smoking (n = 12); and more than 30 pack-years of smoking (n = 30). Diaphragm samples were stained with Picrosirius red and hematoxylin and eosin stain for general structure. RESULTS: Participants with more than 30 pack-years of cigarette smoking had a significant increase in adipocytes, blood vessels and collagen deposit, as well as an increase in histopathological alterations. CONCLUSIONS: Pack-years of smoking was associated with DIAm injury. However, further clinicopathological studies are needed to confirm our findings.

Smoking intensity increases diaphragm muscle injury: a clinicopathologic study

BACKGROUND: Studying the effects of smoking intensity is important to evaluate the risk of tobacco use on a range of illnesses, such as sarcopenia among the elderly. Thus, this study aimed to analyze the effects of pack-years of cigarette smoking on the diaphragm muscle (DIAm) histopathology of postmortem samples. METHODS: Subjects were divided into three groups: never-smoker (n = 46); less than 30 pack-years of smoking (n = 12); and more than 30 pack-years of smoking (n = 30). Diaphragm samples were stained with Picrosirius red and hematoxylin and eosin stain for general structure. RESULTS: Participants with more than 30 pack-years of cigarette smoking had a significant increase in adipocytes, blood vessels and collagen deposit, as well as an increase in histopathological alterations. CONCLUSIONS: Pack-years of smoking was associated with DIAm injury. However, further clinicopathological studies are needed to confirm our findings.

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.

Previous short-term use of testosterone propionate enhances muscle hypertrophy in Wistar rats submitted to ladder-based resistance training.

To investigate the effects of the previous administration of testosterone propionate (TP) on the morphology of the gastrocnemius muscle of Wistar rats submitted to ladder-based resistance training (LRT). Twenty-eight rats were divided equally into groups: initial control (CI), 4-week TP (CT4), 4-week TP + LRT (TRT), and placebo + LRT (RT). The rats from the CT4 and TRT groups were treated with TP for four weeks (10 mg/kg/week). TRT and RT trained for ten weeks. The rodents were euthanized at the end of the experiment, and gastrocnemius muscle, prostate, and left and right testicles were collected. There was no statistical difference between the RT and TRT for final volume load. The prostate mass of the TRT and RT groups was statistically heavier than the CT4 group (P < 0.01). The TRT group's prostate/body mass ratio was statistically different from the CT4 group (P < 0.05). The TRT group was shown to have larger type I, type II, and mean fCSA fibers than all other groups (P < 0.001). Regarding the nuclei/fiber ratio (N/f), the CT4, RT, and TRT groups had higher values than CI (P < 0.01). In addition, the RT group showed a higher N/f ratio than CT4 (P < 0.001) but lower than TRT (P < 0.001). In conclusion, short-term TP administration before resistance training can elicit a greater N/f ratio and size of the mean fCSA of the Gastrocnemius muscle of young adult Wistar rats than resistance training alone.

The sciatic and radial nerves seem to adapt similarly to different ladder-based resistance training protocols.

The present study aimed to compare the morphological response induced by different ladder-based resistance training (LRT) protocols on the peripheral nerve ultrastructure of young adult Wistar rats. Twenty-nine rodents were distributed into groups: control (CON), submaximal (SUBMAX [6 climbs/session, moderate intensity, 3x/week]) and maximum (MAX [> 4 climbs/session, maximum intensity, 3x/week]) LRT. After 8 weeks, the radial and sciatic nerves were removed and prepared for transmission electron microscopy. In the radial nerve, the myelinated fibers and axons, myelin sheath thickness, and unmyelinated axons were statistically greater in the SUBMAX and MAX. The MAX group had greater unmyelinated fibers than SUBMAX. The Schwann cell (SC) nuclei diameter was statistically larger in the SUBMAX than the CON. The number of microtubules and neurofilaments was statistically higher in the SUBMAX and MAX. In the sciatic nerve, the myelinated fibers, myelinated and unmyelinated axons, and myelin sheath thickness were statistically greater in the SUBMAX and MAX. The SUBMAX and MAX had more SC at the nuclei level than CON. The SC nuclei were statistically larger in the SUBMAX and MAX. The number of microtubules and neurofilaments was statistically higher in the SUBMAX and MAX. Total training load and total load per climb were not different between groups. The SUBMAX and MAX statistically increased maximum carried load (ML). In conclusion, the different LRT protocols induced similar morphological responses in radial and sciatic nerves, probably due to load progression and equal total load volume.

Muscle hypertrophy is correlated with load progression delta, climb volume, and total load volume in rodents undergoing different ladder-based resistance training protocols.

We compared the effects of two ladder-based resistance training (LRT) protocols on the skeletal muscle morphology (biceps brachialis and plantaris) of Wistar rats. Also, we correlated the training parameters with the muscle fiber cross-sectional area (fCSA). After maximum load tests (ML), twenty-nine young adult Wistar rats were divided into: CONTROL (n = 9), LIMITED (n = 10, 6-8 climb [2 × 50 %ML, 2 × 75 %ML, 2 × 100 %ML, and 2 × 100 %ML+30 g]) and UNLIMITED (n = 10, ≥4 climbs [50 %ML, 75 %ML, 90 %ML, 100 %ML + 30 g until failure) LRT. After eight weeks, the main results were: 1) For biceps brachialis, the type I, IIa, and mean fCSA was statistically larger in the LIMITED than CONTROL. The nuclei/fiber ratio was statistically higher in the LIMITED and UNLIMITED. The correlations found between total load, absolute delta load, and relative load and fCSA were moderate. 2) For plantaris, the type I, IIa, IIx/b, and mean fCSA was statistically larger in the LIMITED than CONTROL. The type IIa, IIx/b, and mean fCSA was statistically larger in the UNLIMITED than CONTROL. The nuclei/fiber ratio was statistically higher in both trained groups than CONTROL. The correlation between the climbing number, total load, and the fCSA was moderate. The correlation between delta absolute load and fCSA was strong. We concluded that rodents submitted to high-intensity, high-volume LRT, but limited climbing volume per session, presented more significant type I, IIa, IIx/b, and mean fCSA, higher nuclei/fiber ratio, and greater maximum carrying capacity. Also, muscle hypertrophy correlated positively with the load progression, training volume, and total load.

Ladder-based resistance training elicited similar ultrastructural adjustments in forelimb and hindlimb peripheral nerves of young adult Wistar rats.

To analyze the morphological response induced by high-volume, high-intensity ladder-based resistance training (LRT) on the ultrastructure of the radial (forelimb) and sciatic (hindlimb) nerves of adults Wistar rats. Twenty rats were equally distributed into groups: sedentary (SED) and LRT. After the rodents were subjected to the maximum load (ML) carrying test, the LRT group performed 6-8 progressive climbs (2 × 50% ML, 2 × 75% ML, 2 × 100% ML, and 2 × 100% ML + 30 g) three times per week. After 8 weeks, the radial and sciatic nerves were removed and prepared for transmission electron microscopy. In the radial nerve, myelinated axons cross-sectional area (CSA), unmyelinated axons CSA, myelin sheath thickness, and Schwann cells nuclei area were statistically larger in the LRT group than SED (p < 0.05). Also, the number of microtubules and neurofilaments per field were statistically higher in the LRT group than in SED (p < 0.01). For sciatic nerve, myelinated fibers CSA, unmyelinated axons CSA, myelin sheath thickness, Schwann cells nuclei area, and the number of neurofilaments per field were statistically larger in the LRT group compared to the SED group (p < 0.05). LRT with high-volume and high-intensity effectively induce similar changes in adult Wistar rats' radial and sciatic nerves' ultrastructure.

Evaluation of the Diaphragm Muscle Remodeling, Inflammation, Oxidative Stress and Vascularization in Smokers: An Autopsy Study.

BACKGROUND/AIMS: Cigarette smoking is a key factor in systemic inflammation and oxidative stress, and it has also been associated with the loss of muscle strength and an elevated risk of pulmonary diseases. Thus, this study aimed to analyze the effects of cigarette smoking on the diaphragm muscle structure of postmortem samples. METHODS: Immunohistochemical techniques were used for muscle remodeling (metalloproteinases 2 and 9), inflammation (cyclooxygenase-2), oxidative stress (8-hydroxy-2'-deoxyguanosine), and vascularization (vascular endothelial growth factor). Hematoxylin and eosin stain was used for histopathological analysis and Picrosirius stain was used to highlight the collagen fibers. RESULTS: Cigarette smokers had an increase of diaphragm muscle remodeling, oxidative stress, inflammation, and vascularization compared to non-smokers. CONCLUSION: Diaphragm muscle structure may be negatively affected by cigarette smoking.

Diaphragm muscle structure in the elderly: Findings from an autopsy study.

Sarcopenia is characterized as aging-related weakness and atrophy, which decreases the diaphragm force generating capacity leading to a decrease of expulsive non-ventilatory motor behaviors, which are critical for airway clearance. Thus, this study aimed to analyze the histopathology of the diaphragm in postmortem samples. Thirty individuals were included. Diaphragm samples were stained with hematoxylin and eosin for histopathological analysis. Picrosirius stain was used to highlight the collagen fibers. We observed a positive association between advancing age and histopathological findings in the diaphragm structure. We suggest that age is a key factor in increasing diaphragm muscle histopathology. However, further clinicopathological studies are needed to confirm our findings.

Cigarette Smoking Impairs the Diaphragm Muscle Structure of Patients without Respiratory Pathologies: An Autopsy Study.

BACKGROUND/AIMS: Smoking is a major risk factor for several cardiovascular and pulmonary diseases, and it has also been associated with the loss of skeletal muscle mass and strength leading to sarcopenia. The aim of this is study is to analyze the effects of cigarette smoking on the diaphragm muscle histopathology of postmortem samples from patients without respiratory diseases. METHODS: Diaphragm samples were stained with hematoxylin and eosin for histopathological analysis. Picrosirius stain was used to highlight the collagen fibers. RESULTS: Cigarette smokers had an increase of histopathological alterations as abnormal cytoplasm, abnormal fiber size and shape, and central nucleus. Additionally, smokers had an increase of collagen fibers on diaphragm muscle. CONCLUSION: Smoking may influence in a negatively fashion the diaphragm musculature.

Effects of resistance training on liver structure and function of aged rats.

The aging process may cause negative physiological changes. However, exercises as resistance training (RT) have been considered an important intervention to attenuate these changes. Additionally, liver plays an important role in blood glucose homeostasis in exercise. AIM: This study aimed to analyze the effects of RT on the liver components of aged animals. METHODS: Male Wistar rats were divided into two groups: 24 months' group (CONTROL); and group submitted to a progressive RT protocol for 16 weeks (EXERCISE). Both groups were sacrificed at 24 months. RESULTS: We observed a decrease in blood flow due to the practice of resistance exercises. Besides, our results showed that hepatic tissue plays an important role in glycemic homeostasis during RT. In addition, RT increased mitogen capacity of hepatocytes. CONCLUSIONS: Our study showed many implications for the knowledge about the effects of strength training on old animals' liver.

Divergent effects of resistance training and anabolic steroid on the postsynaptic region of different skeletal muscles of aged rats.

This study aimed to analyze the effects of resistance training associated with testosterone administration in the neuromuscular junction (NMJ) postsynaptic region of different skeletal muscle types of aged rats. Wistar rats were divided into: SEI - 20-months-old control, SEF - 24-months-old control, T - 20-months-old with testosterone, S - 20-months-old resistance trained and ST - 20-months-old with resistance training associated with testosterone propionate. All groups were submitted to familiarization and maximum load carrying testing (MLCT). The MLCT was applied before and after the resistance training (RT) period. RT (6-8×/session with progressive loads of 50 to 100%, 3×/week and 120s interval) was performed in ladder climbing for 15weeks. The administration of testosterone propionate was performed 2×/week (10mg/kg/body weight). After euthanize, soleus and plantaris muscles were removed and prepared for histochemistry and cytofluorescence. T, S and ST significantly increased their maximum carrying load capacity compared to SEI and SEF (p<0.05). For soleus postsynaptic region, ST had lower total and stained area than SEF (p<0.05). For plantaris, the postsynaptic component of T was statistically larger than SEI (p<0.05). For soleus histochemistry, T, S and ST groups showed the same magnitude of type I myofibers hypertrophy, thus statistically different from SEI and SEF (p<0.05). The cross-sectional area of the type IIa myofibers of the ST was larger than SEF (p<0.05). The volume density of type I myofibers show to be lower in ST than SEI (p<0.05). As for type IIa myofibers, ST increased Vv [type IIa] compared to SEI and SEF (p<0.05). For plantaris, T significantly hypertrophied type I myofibers compared to SEI and SEF (p<0.05). S and ST demonstrated significant increases of type I myofibers compared to SEI and SEF (p<0.05). As for type IIx myofibers, both S and ST showed myofibers larger than SEI (p<0.05). However, only the ST had significant difference compared to SEF (p<0.05). In conclusion, both therapies, alone or combined, have little effect on the morphology of the NMJ postsynaptic region of distinct muscles. Moreover, the three therapies are potentially stimulating for strength gains and muscle hypertrophy.

Effects of testosterone administration on liver structure and function in aging rats.

Aging males have a decrease in testosterone levels, by which the testosterone treatment may influence in a negatively fashion the liver. AIM: This study aimed to analyze the effects of aging with or without testosterone administration on the liver components of animals. METHODS: Wistar rats were divided into three groups: 20 months' group (G20), 24 months' group (G24), group treated with testosterone for 16 weeks (GT). All groups were sacrificed at 24 months except for G20 that was sacrificed at 20 months. RESULTS: Aging and testosterone treatment alters the body weight (BW), liver weight (LW) and relative liver weight. Besides, testosterone increased the mitogen capacity of hepatocytes. Nonetheless, we reinforce the negative effects of testosterone on old animals' liver as chronic hepatic congestion and/or cholestasis. In addition, we observed that testosterone plays an important role on hepatic glycogen stores. CONCLUSIONS: Our study showed many implications for the knowledge about the effects of aging with or without testosterone administration on old animals' liver.

Effects of exercise on neuromuscular junction components across age: systematic review of animal experimental studies.

BACKGROUND: During almost one-third of our life, maturation of the nervous system promotes strength and muscle mass increase. However, as age advances, the nervous system begins to suffer a slow and continue reduction of its functions. Neuromuscular junction (NMJ) is one of the structures of which change due to aging process. Physical training leads to significant adjustments in NMJs of young and aged animals. Nevertheless, studies that aimed to investigate this effect have, in many cases, methodological variables that may have some influence on the result. Thus, this study aimed to carry out a systematic review about the effects of exercise training on the NMJ compartments of young, adult and aged animals. RESULTS: We searched PubMed, Google Scholar, Science Direct, Scielo and Lilacs databases for animal experimental studies that studied exercise effects on the NMJs components across age. After inclusion and exclusion criteria, we included nine articles in systematic review and two for meta-analysis (young/adult NMJ). CONCLUSIONS: We identified that exercise training cause NMJ hypertrophy on young animals and NMJ compression on aged ones. However, many methodological issues such as age, skeletal muscle and fibers type, and type of exercise and training protocol might influence the results. Graphical abstract: Flow gram is actually to be show at results section as Fig 1.

Morfologia e histoquímica do tecido muscular esquelético de ratos após estiramento / Morphological and histochemical skeletal muscle tissue of rats after stretch

A lesão muscular constitui parte integrante do processo de adaptação a certos tipos de treinamento físico. Em atletas altamente treinados, a lesão muscular, representa uma resposta capaz de acelerar o turnover protéico. O presente trabalho teve por finalidade avaliar a morfologia, e as características metabólicas e contráteis dos tipos de fibras musculares. Foram utilizados 10 ratos Wistar com peso corporal médio de 350g com idade de 70 dias. Os animais foram submetidos a um estímulo elétrico (tetania) e a um estímulo mecânico (estiramento). Após 48h os animais foram eutanasidos mediante uma dose de pentobarbital sódico. Fragmentos da cabeça medial do músculo gastrocnêmio foram imersas em N-Hexana a -70º Cortes (8 µm) obtidos em um micrótomo criostato, (–20ºC), foram corados pela HE e outros submetidos as reações NADH-TR e m ATPase, (pH 4,6 e 10,4). O padrão fascicular mostrou-se desorganizado. Ao lado de várias fibras com diferentes estágios de fagocitose, observou-se um intenso infiltrado plasmolinfocitarios, com elevado numero de macrófagos, células miosatélites e células mesenquimatosas, e áreas com ausência de células musculares. A atividade oxidativa revelou-se levemente aumentada em todos os tipos de fibras normais e muito diminuída nas fibras em fase de fagocitose. Conforme revelado pela reação m-ATPase, após pré-incubação alcalina e ácida, lesões foram observadas nas fibras de contração lenta (Tipo I) e nas de contração rápida (Tipo II). Assim, decorridas 48h após o estímulo de tetania e estiramento mecânico, a lesão de fibras acompanhada de processo de fagocitose e o infiltrado de células miosatélites, macrófagos e células mesenquimatosas, foram os eventos mais evidentes. Em nível do tipo de fibras, as lesões comprometeram ambos os tipos.

Muscular injury constitutes an integral part of the adaptation process to certain types of physical training. In highly trained athletes, muscular injury, or so it seems, represents a response capable of speeding up the protein turnover. The goal of the present work was to evaluate the degree of morphologic alteration, as well as the metabolic and contractile characteristics of types of muscle fibers. Ten Wistar rats were used with an average corporal weight of 350g. The animals were submitted to both an electrical stimulation (tetany) and a mechanical stimulation (stretching). After 48h the animals were euthanized by means of a dose of pentobarbital, followed by the removal of the medial head of the gastrocnemius muscle. The muscular samples were first immersed in N-Hexan at -70°C, and then placed in a microtome cryostat at -20°C, where transversal cuts (8 µm) at the longest axle of staple fibers were obtained. Some cuts were submitted to HE and others to the reactions for NADH-TR and mATPase, (pH 4.6 and 10.4). In addition to some staple fibers in different stages of phagocytosis, an intense infiltration was observed, with a large number of macrophages, mesenchyma and myosatellite type cells, and areas with an absence of muscular cells. The oxidative activity was seen to be slightly augmented in all types of normal fibers but significantly decreased in fibers in the phagocytosis phase. As revealed by the m ATPase reaction after the acid and alkaline pre-incubation phase, lesions were observed in the two types of fibers, slow and fast contraction (Type I e II). Thus, 48 hours after the tetany/stretching, the lesion of fibers followed by the phagocytosis process and the infiltration of myosatellite cells, macrophages and mesenchymal cells were the most observed events. Regarding the types of fibers, the lesion seems to compromise both types.

Morphological changes in distant muscle fibers following thermal injury in Wistar rats.

PURPOSE: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45% of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45% of the body surface.

Morphological changes in distant muscle fibers following thermal injury in Wistar rats / Alterações morfológicas das fibras musculares de um músculo distante da lesão térmica em ratos Wistar

PURPOSE: Thermal injury causes catabolic processes as the body attempts to repair the damaged area. This study evaluated the effects of a scald injury on the morphology of muscle fibers belonging to a muscle distant from the lesion. METHODS: Thirty Wistar rats were divided into control (C) and scalded (S) groups. Group S was scalded over 45 percent of the body surface, standardized by body weight. Rats in both groups were euthanized at four, seven and 14 days following the injury. The middle portions of the medial gastrocnemius muscles were sectioned, stained with hematoxylin and eosin and Picrosirius, and submitted to histological analysis. RESULTS: Control group sections exhibited equidistantly distributed polygonal muscle fibers with peripheral nuclei, characteristic of normal muscle. The injured group sections did not consistently show these characteristics; many fibers in these sections exhibited a rounded contour, variable stain intensities, and greater interfiber distances. A substantially increased amount of connective tissue was also observed on the injured group sections. CONCLUSION: This experimental model found a morphological change in muscle distant from the site of thermal injury covering 45 percent of the body surface.

OBJETIVO: A lesão térmica conduz o organismo a processos catabólicos a fim de reparar a área lesada. O propósito do presente estudo foi avaliar os efeitos da lesão térmica por escaldadura na morfologia das fibras musculares de um músculo distante da lesão. MÉTODOS: Foram utilizados 30 ratos Wistar, divididos em: Grupo submetido à lesão térmica por escaldadura (S) e Grupo Controle (C). A escaldadura foi provocada em 45 por cento da superfície corporal dos animais e padronizada pelo peso corpóreo. A eutanásia ocorreu nos períodos pós-lesão de quatro, sete e 14 dias. Retirou-se a parte média dos músculos gastrocnêmio medial os quais foram submetidos à técnica histológica de Hematoxilina-Eosina e Picrosírius. RESULTADOS: O aspecto poligonal das fibras musculares, com núcleos periféricos, bem como a distribuição eqüidistante das mesmas, característico das descrições da musculatura normal, verificado nos animais do grupo C não foi uma constante nas fibras do músculo dos animais do grupo S. Nestes, muitas fibras exibiram contorno arredondado, diferentes intensidades de marcação bem como maior distanciamento entre as mesmas. Observou-se ainda aumento substancial da quantidade de tecido conjuntivo no grupo S. CONCLUSÃO: Houve alteração da morfologia do músculo distante da lesão como resposta à lesão térmica de 45 por cento em modelo experimental.

Effect of GaAlAs laser irradiation on the epiphyseal cartilage of rats.

OBJECTIVE: To study the effect of an 830-nm gallium-aluminum-arsenic (GaAlAs) diode laser at two different energy densities (5 and 15 J/cm(2)) on the epiphyseal cartilage of rats by evaluating bone length and the number of chondrocytes and thickness of each zone of the epiphyseal cartilage. BACKGROUND DATA: Few studies have been conducted on the effects of low-level laser therapy on the epiphyseal cartilage at different irradiation doses. MATERIALS AND METHODS: A total of 30 male Wistar rats with 23 days of age and weighing 90 g on average were randomly divided into 3 groups: control group (CG, no stimulation), G5 group (energy density, 5 J/cm(2)), and G15 group (energy density, 15 J/cm(2)). Laser treatment sessions were administered every other day for a total of 10 sessions. The animals were killed 24 h after the last treatment session. Histological slides of the epiphyseal cartilage were stained with hematoxylin-eosin (HE), photographed with a Zeiss photomicroscope, and subjected to histometric and histological analyses. Statistical analysis was performed using one-way analysis of variance followed by Tukey's post hoc test. All statistical tests were performed at a significance level of 0.05. RESULTS: Histological analysis and x-ray radiographs revealed an increase in thickness of the epiphyseal cartilage and in the number of chondrocytes in the G5 and G15 groups. CONCLUSION: The 830-nm GaAlAs diode laser, within the parameters used in this study, induced changes in the thickness of the epiphyseal cartilage and increased the number of chondrocytes, but this was not sufficient to induce changes in bone length.

The effects of a 785-nm AlGaInP laser on the regeneration of rat anterior tibialis muscle after surgically-induced injury.

OBJECTIVE: This study aims to investigate the effects of low-level laser therapy (LLLT) on muscle regeneration. For this purpose, the anterior tibialis muscle of 48 male Wistar rats received AlGaInP laser treatment (785 nm) after surgically-induced injury. BACKGROUND DATA: Few studies have been conducted on the effects of LLLT on muscle regeneration at different irradiation doses. MATERIALS AND METHODS: The animals were randomized into four groups: uninjured rats (UN); uninjured and laser-irradiated rats (ULI); injured rats (IN); and injured and laser-irradiated rats (ILI). The direct contact laser treatment was started 24 h after surgery. An AlGaInP diode laser emitting 75 mW of continuous power at 785 nm was used for irradiation. The laser probe was placed at three treatment points to deliver 0.9 J per point, for a total dose of 2.7 J per treatment session. The animals were euthanized after treatment sessions 1, 2, and 4. Mounted sections were stained with hematoxylin and eosin and used for quantitative morphological analysis, in which the number of leukocytes and fibroblasts were counted over an area of 4480 mum(2). The data were statistically analyzed by analysis of variance (ANOVA) and the Bonferroni t-test. RESULTS: Quantitative data showed that the number of both polymorphonuclear and mononuclear leukocytes in the inflammatory infiltrate at the injury site was smaller in the ILI(1), ILI(2), and ILI(4) subgroups compared with their respective control subgroups (IN(1), IN(2), and IN(4)) for sessions 1, 2, and 4, respectively (p < 0.05). On the other hand, the number of fibroblasts increased after the fourth treatment session (p < 0.05). With regard to the regeneration of muscle fibers following injury, only after the fourth treatment session was it possible to find muscle precursor cells such as myoblasts and some myotubes in the ILI(4) subgroup. CONCLUSION: During the acute inflammatory phase, the AlGaInP laser treatment was found to have anti-inflammatory effects, reducing the number of leukocytes at the injury site and accelerating the regeneration of connective tissue.

Análise qualitativa dos efeitos da fonoforese com Arnica montana sobre o processo inflamatório agudo do músculo esquelético de ratos / Qualitative analysis of effects of phonophorese with Arnica montana onto acute inflammatory process in rat skeletal muscles

Este estudo visou verificar o efeito da fonoforese com Arnica montana sobre a fase inflamatoria aguda de uma lesão muscular. Para isso, 40 ratos Wistar machos, lesados cirurgicamente, foram divididos em 4 grupos: controle (C), 10 ratos lesados e não tratados grupo ultra-som (US), 10 lesados tratados com fonoforese de gel de arnica; grupo arnica (A), 10 ratos lesados, tratados com massagem de gel de arnica...

This study aimed at verifying the effects of phonophoresis associated to Arnica montana on the acute phase of an inflammatory muscle injury. Forty Wistar male rats of which the Tibialis. Anterior muscle was surgically lesioned, were divided into 4 groups (n+10 each); control group received no treatment the ultrasound group (US), treat with US; the US+A group was treat with arnica phonophoresis...