Analysis of the muscle tissue of Wistar rats submitted to the sciatic nerve compression model and cryotherapy

Analysis of Wistar Rats Submitted to a Gout Model, Treated with Double Cryotherapy Protocol

Gout arthritis commonly affects joint regions by deposition of crystals, promoting functional damage mainly during periods of exacerbation. Cryotherapy is a commonly used resource to contain inflammatory processes, however, its use during a gout crisis is not yet well understood. Therefore, the objective was to evaluate the parameters of Wistar rats submitted to an experimental gout model and treated with dual cryotherapy protocol. Twenty-one male Wistar rats were used, separated into three groups: control group (CG), lesion group (LG), and lesion + cryotherapy group (LCG). Gout model induction was through intra-articular injection, with urate crystal solution, in the right knee and cryoimmersion treatment was performed for 20 minutes at a temperature of 5° ± 2°C. Seven evaluations and two treatment moments were performed, and the following parameters were analyzed: joint edema, grip strength, joint disability, motor function, and leukocyte migration through synovial lavage. In the statistical analysis we used SPSS 20.0 with Generalized Linear Models, with least significant difference posttest, always with 5% significance level. The treatment reduced edema, promoted strength recovery, and was effective in reducing total leukocytes in the synovial fluid. No difference was observed between the injured groups for joint disability and motor function. Cryotherapy promoted edema reduction and increased pelvic limb grip strength in Wistar rats during the acute period.

Low-Level Laser Therapy in Different Wavelengths on the Tibialis Anterior Muscle of Wistar Rats After Nerve Compression Injury

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, lesion + 660-nm laser, and lesion + 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.