Elisangela Lourdes Artifon

Low-level laser therapy, at 830 nm, for pain reduction in experimental model of rats with sciatica

Chronic pain, resulting from nerve compression, is a common clinical presentation. One means of conservative treatment is low-level laser therapy, although controversial. The aim of this study was to evaluate the effects of two doses of low-level laser, at 830 nm, on pain reduction in animals subjected to sciatica. Eighteen rats were used, divided into three groups: GS (n=6), sciatica and simulated treatment; G4J (n=6), sciatica and treatment with 4 J/cm²; and G8J (n=6), sciatica and irradiation with 8 J/cm². The right sciatic nerve was exposed and compressed using catgut thread. Five days of treatment were started on the third postoperative day. Pain was assessed by means of the paw elevation time during gait: before sciatica, before and after the first and second therapies, and the end of the fifth therapy. Low-level laser was effective in reducing the painful condition.

Avaliação do exercício físico como fator de analgesia em um modelo experimental de ciatalgia

OBJECTIVE: To evaluate the efficacy of physical exercise (swimming and jumping), with and without overload, working in reducing the pain of rats undergone to an experimental model of sciatica. METHODS: 24 rats were divided into four groups: Placebo (GP), Swimming Group (NG) Swimming 10% Group (GN10) and Leap Group (GS). All groups were submitted to the experimental sciatica model and assessed for pain post-exercise for the Functional Disability Test and the Von Frey filament. RESULTS: In comparison within groups there were significant differences in the moments after injury with the pre-injury, for both assessment instruments. With Von Frey filament was observed a significant difference in group GN10 and GS in the final moments of evaluation. In comparisons between groups were not statistically significant differences obtained with any assessment instrument. CONCLUSION: Treatment with physical exercise was not effective in reducing pain in rats subjected to experimental sciatica model.

Treinamento aeróbico prévio à compressão nervosa: análise da morfometria muscular de ratos

INTRODUCTION: Sciatica stems from compression of the sciatic nerve and results in pain, paresthesia, decreased muscle strength and hypertrophy. Exercise is recognized in the prevention and rehabilitation of injuries, but when performed in overload, it may increase the risk of injury and subsequent functional deficit. OBJECTIVE: To evaluate effects of aerobic training prior to an experimental model of sciatic pain concerning morphometric parameters of soleus muscles of rats. MATERIALS AND METHODS: 18 rats were divided into three groups: sham (dip, 30 seconds), regular exercise (swimming, 10 minutes daily) and progressive aerobic training (swimming, progressive time from 10 to 60 minutes daily). After six weeks of exercise, rats were subjected to the experimental model of sciatic pain. On the third day after injury, they were killed and their soleus muscles were dissected, weighed and processed for histological analysis. The analyzed variables were: muscle weight, cross-sectional muscle area and mean diameter of muscle fibers. RESULTS: Statistically significant difference was observed for all groups when compared to control muscle and that submitted to sciatic injury. Intergroup analysis showed no statistically significant difference for any of the variables. CONCLUSION: Both regular physical exercise and aerobic training had no preventive or aggravating effects on the consequences of functional inactivity after sciatica.

The Effects of Low-Level Laser Therapy, 670 nm, on Epiphyseal Growth in Rats

The longitudinal growth of long bones is attributed to epiphyseal growth. However, the effects of low-level laser therapy (LLLT) in such structures has still not been studied extensively in the literature. Therefore, the aim of this study was to evaluate the use of LLLT, 670 nm, at three different doses on the epiphyseal growth of the right tibia of rats. Twenty-one Wistar rats, aged four weeks, were subjected to the application of LLLT, with dosage according to the group (G4: were submitted to the application of 4 J/cm2; G8: were submitted to the application of 8 J/cm2; G16: were submitted to the application of 16 J/cm2). After completion of protocol they were kept until they were 14 weeks of age and then submitted to a radiological examination (evaluation of limb length) and euthanised. The histological analysis of the growth plates (total thickness and hypertrophic and proliferative zones) was then performed. Comparisons were made with the untreated left tibia. No differences were observed in any of the reviews (radiological and histological), when comparing the right sides (treated) to the left (untreated). It was concluded that the treatment with LLLT within the parameters used caused changes neither in areas of the epiphyseal cartilage nor in the final length of limbs.

Swimming training and functional assessment of sciatic nociception in rats

INTRODUCTION The protective effect of exercise on individuals with peripheral neuropathy is controversial. OBJECTIVE To assess the influence of physical training of moderate and progressive intensity on nociception of rats in an experimental sciatica model. MATERIALS AND METHODS The study assessed 18 rats divided into the following three groups: control group (CG); low-intensity swimming group (LISG); progressive-time swimming group (PTSG). To meet the physical training protocol, the animals were placed in a water tank for six weeks, three alternate days per week. In LISG group, the animals swam ten minutes per session, and, in PTSG group, the animals began swimming for ten minutes, and had a ten-minute increase per week. In CG group, the animals swam less than one minute per day, only to get used to the water environment. After finishing the swimming training, the experimental sciatica model protocol was started with constrictive ligature of the sciatic nerve with chromic catgut. Nociception was assessed using the functional disability test, which measures, in a one-minute interval, the time during which the animal holds its hind paw (THHP) in a guarded position. Assessments were performed preoperatively, and on the third, sixth, and tenth post-operative (PO) days. RESULTS All groups showed a significant increase in THHP on third, sixth, and tenth PO days, as compared to preoperative values. In CG, no significant change was observed in PO assessments, unlike what happened in LISG and PTSG groups. CONCLUSION Exercise produced greater hyperalgesia.

Efeitos do ultrassom terapêutico associados ao alongamento estático sobre parâmetros histomorfométricos longitudinais de sóleos imobilizados de ratos

The muscle tissue is endowed with plasticity that adapts to different stimuli. Immobilization causes damage to the musculature including atrophy, loss of muscle strength and extensibility. The stretching and ultrasound treatment modalities are used to speed up muscle repair process as they can increase protein synthesis and improve extensibility. OBJECTIVE: To compare the use of therapeutic thermal and non thermal ultrasound, associated with stretching, in the remobilization of the soleus muscle of rats subjected to position of muscle shortening on aspects histomorphometric longitudinal muscle.} METHODS: 28 rats were immobilized for 15 days, later released from the apparatus and divided into four groups: group AG only remobilized by stretching for 10 days and the others were subjected to 10 days of therapeutic intervention 1MHz of ultrasound at 1.0W/cm² (GAUS 1.0), 0.5W/cm² (GAUS 0.5), and 0.2 W/cm² (GAUS 0.2), and further stretching to the soleus. At the end of treatment, the animals were sacrificed and their soleus muscles were removed for later histological analysis of longitudinal parameters (count of sarcomeres). RESULTS: At intragroup analysis on the muscle length, only the group GAUS 0.5 did not present significant difference. The count of sarcomeres in the groups GA and GAUS 0.2 was statistically different. The size of the sarcomeres in both groups had no statistically significant difference. In inter-group analysis both groups had no statistically significant difference for any of the variables. CONCLUSION: The stretching was insufficient to reverse the effects of immobilization. When associated with therapeutic ultrasound, the dose 0.5 W/cm² recovered muscle length significantly, and the doses 1.0 and 0.5 W/cm² contributed to the significant increase of the number of sarcomeres in immobilized muscles.

Evaluación del tropismo del músculo sóleo de ratas wistar después de la compresión del nervio y tratamiento con corriente de alto voltaje

OBJETIVO: Evaluar la corriente de alto voltaje en el tropismo del soleo de ratas con la compresion del nervio ciatico. Dieciocho ratas se dividieron en: GS - compresion del nervio y la falsa; GP+ - compresion y tratados con corriente anodica; GP- - compresion y el catodo. Por ultimo, fueron los soleos disecados y pesados ​​en una balanza analitica. Luego diapositivas de secciones transversales fueron montadas para la observacion al microscopio de luz comun y digitalizadas para el analisis de menor diametro de 100 fibras por musculo. RESULTADOS: Todos los grupos mostraron menor tropismo, las dos formas de evaluacion (p 0,05). CONCLUSION: La corriente de alto voltaje no inhibe la atrofia en el musculo soleo se sometieron a la compresion del nervio.Objetivo: avaliar a corrente de alta voltagem sobre o trofismo de soleos de ratos com compres- sao de nervo isquiatico. Dezoito ratos distribuidos em: GS – compressao nervosa e simulacro; GP+ – compressao e tratado com corrente anodica; GP- – compressao e catodica. Ao final, os soleos foram dissecados e pesados em balanca analitica. Em seguida foram montadas lâminas de cortes transversais, observadas em microscopio optico de luz comum e digitalizadas, para analise do menor diâmetro de 100 fibras por musculo. Resultados: todos os grupos apresentaram menor trofismo pelas duas formas de avaliacao (p 0,05). Conclusao: a corrente de alta voltagem nao inibiu a hipotrofia em soleos submetidos a compressao nervosa.

Avaliação do trofismo muscular de sóleos de ratos wistar após compressão nervosa e tratamento com corrente de alta voltagem

OBJETIVO: Evaluar la corriente de alto voltaje en el tropismo del soleo de ratas con la compresion del nervio ciatico. Dieciocho ratas se dividieron en: GS - compresion del nervio y la falsa; GP+ - compresion y tratados con corriente anodica; GP- - compresion y el catodo. Por ultimo, fueron los soleos disecados y pesados ​​en una balanza analitica. Luego diapositivas de secciones transversales fueron montadas para la observacion al microscopio de luz comun y digitalizadas para el analisis de menor diametro de 100 fibras por musculo. RESULTADOS: Todos los grupos mostraron menor tropismo, las dos formas de evaluacion (p 0,05). CONCLUSION: La corriente de alto voltaje no inhibe la atrofia en el musculo soleo se sometieron a la compresion del nervio.Objetivo: avaliar a corrente de alta voltagem sobre o trofismo de soleos de ratos com compres- sao de nervo isquiatico. Dezoito ratos distribuidos em: GS – compressao nervosa e simulacro; GP+ – compressao e tratado com corrente anodica; GP- – compressao e catodica. Ao final, os soleos foram dissecados e pesados em balanca analitica. Em seguida foram montadas lâminas de cortes transversais, observadas em microscopio optico de luz comum e digitalizadas, para analise do menor diâmetro de 100 fibras por musculo. Resultados: todos os grupos apresentaram menor trofismo pelas duas formas de avaliacao (p 0,05). Conclusao: a corrente de alta voltagem nao inibiu a hipotrofia em soleos submetidos a compressao nervosa.

Assessment of wistar rats' soleus muscle trophism after nerve compression and treatment with high-voltage current

OBJETIVO: Evaluar la corriente de alto voltaje en el tropismo del soleo de ratas con la compresion del nervio ciatico. Dieciocho ratas se dividieron en: GS - compresion del nervio y la falsa; GP+ - compresion y tratados con corriente anodica; GP- - compresion y el catodo. Por ultimo, fueron los soleos disecados y pesados ​​en una balanza analitica. Luego diapositivas de secciones transversales fueron montadas para la observacion al microscopio de luz comun y digitalizadas para el analisis de menor diametro de 100 fibras por musculo. RESULTADOS: Todos los grupos mostraron menor tropismo, las dos formas de evaluacion (p 0,05). CONCLUSION: La corriente de alto voltaje no inhibe la atrofia en el musculo soleo se sometieron a la compresion del nervio.Objetivo: avaliar a corrente de alta voltagem sobre o trofismo de soleos de ratos com compres- sao de nervo isquiatico. Dezoito ratos distribuidos em: GS – compressao nervosa e simulacro; GP+ – compressao e tratado com corrente anodica; GP- – compressao e catodica. Ao final, os soleos foram dissecados e pesados em balanca analitica. Em seguida foram montadas lâminas de cortes transversais, observadas em microscopio optico de luz comum e digitalizadas, para analise do menor diâmetro de 100 fibras por musculo. Resultados: todos os grupos apresentaram menor trofismo pelas duas formas de avaliacao (p 0,05). Conclusao: a corrente de alta voltagem nao inibiu a hipotrofia em soleos submetidos a compressao nervosa.

Use of high-voltage cathodic current for pain in experimental nerve compression

OBJECTIVE To assess the effect of high-voltage cathodic current on pain from a sciatica experimental model. METHODS A total of 16 male Wistar rats were submitted to the sciatica experimental model in the right hind paw. They were divided into sham group (GS) and group treated with cathodic current (GP-) for 20 min/daily, for 10 days). The model of sciatic compression was performed with a 4.0-chromic catgut thread tie in four points of the sciatic nerve. Assessment of nociception was performed by measuring the time during which the animal held its hind paw in a guarded position (THHP) and the pressure withdrawal threshold, by use of a digital electronic analgesymeter. Data collection was carried out before the sciatica experimental model (AS1), three days after compression (before, AS2, and after treatment, AS3), and five and 10 days after treatment (AS4 and AS5, respectively). RESULTS According to the functional disability test, both groups showed an increase in nociception, with no reduction at any assessment time. Submitted to pressure, however, GS showed a reduction in the hind paw withdrawal threshold at all assessment times, while GP- showed a reduction in the hind paw withdrawal threshold only initially - at AS5, the threshold was restored. CONCLUSION No change in nociception was observed on functional assessment; however, on pressure hind paw withdrawal assessment, the treatment with cathodic current showed to be effective with the summation of therapies.