RESUMO
OBJECTIVE: Traumatic injuries are common and may promote disruption of neuromuscular communication, triggering phenomena that lead to nerve degeneration and affect muscle function. A laser accelerates tissue recovery; however, the parameters used are varied, making it difficult to compare studies. The purpose of this study was to evaluate the effect of low-level laser therapy, at 660- and 830-nm wavelengths, on the tibialis anterior muscle of Wistar rats after sciatic nerve compression. METHODS: Twenty animals were separated into 4 groups: control, sciatic nerve injury, lesionâ¯+â¯660-nm laser, and lesionâ¯+â¯830-nm laser. In the lesion groups, the right sciatic nerve was surgically exposed and compressed with hemostatic forceps for 30 seconds. After the third postoperative day, the groups with laser therapy were submitted to treatment for 2 weeks totaling 10 applications, performed directly on the surgical scar of the nerve injury. Grip strength was analyzed before and after the nerve injury and during the treatment period. The tibialis anterior muscle was processed for light microscopy, area measurement, smaller diameter, number of fibers, nuclei, and connective tissue. RESULTS: The animals submitted to the injury experienced muscular atrophy and morphological changes in the number of muscle fibers and nuclei. In the connective tissue morphometry, there was a decrease in the treated groups compared with the untreated groups. CONCLUSION: The laser treatment at different wavelengths showed no improvement in the tibialis anterior muscle of Wistar rats within the morphological and functional aspects evaluated.
Assuntos
Terapia com Luz de Baixa Intensidade/métodos , Músculo Esquelético/efeitos da radiação , Traumatismos dos Nervos Periféricos/radioterapia , Neuropatia Ciática/radioterapia , Animais , Tecido Conjuntivo/patologia , Ratos , Ratos Wistar , Nervo Isquiático/efeitos da radiação , Neuropatia Ciática/fisiopatologiaRESUMO
OBJECTIVE: The purpose of this study was to analyze the morphometric effects of mechanical vibration with a duration of 4 or 8 weeks on the femur of oophorectomized Wistar rats. METHODS: Sixty-four female rats were submitted to oophorectomy or a sham operation, and each of those 2 groups were randomized into 4 groups: untreated and euthanized at week 12, untreated and euthanized at week 16, treated for 4 weeks and euthanized at week 12, and treated for 8 weeks and euthanized at week 16. The vibration treatment was performed for 10 min/d, with a frequency of 60 Hz, 3 d/wk. The rats were then euthanized and the right femur dissected. Subsequently, histomorphometric analysis was performed on the proximal epiphysis and diaphysis of the spongy and cortical bone, respectively. RESULTS: As expected, the oophorectomy groups presented reduction of spongy and cortical bone tissue. Further, the vibration therapy of 4 and 8 weeks' duration in the oophorectomized groups led to increased bone mass, observed as an increased percentage of spongy tissue, and increased thickness and percentage of cortical tissue. However, the variables of femoral neck diameter, mean area of the shaft, and number of osteocytes were not altered by oophorectomy and vibration. CONCLUSION: The mechanical vibration was effective in increasing the bone mass of the femur of oophorectomized Wistar rats, observed by increasing the percentage of spongy bone and increasing the percentage and thickness of cortical bone.