Efeito do laser de baixa intensidade (660 nm) na regeneração do nervo isquiático lesado em ratos

Photobiomodulation promotes neural regeneration when compared to simvastatin treatment in a sciatic nerve crush model

To determine whether the effects of photobiomodulation (PBM) were associated with the use of Simvastatin in the functional recovery from sciatic nerve in mice submitted to crush injury. Fifty Swiss mice (approximately 3 months old; average weight 40 g) were randomly divided into six groups: naive, sham, control, PBM (660 nm, 10 J/cm2; 30 mW; 0.6 J per day for 28 days; 0.06 cm2; 16.8 J total and 20 s), Simvastatin (20 mg/kg), and PBM/Simv (association of the two protocols). The sciatic functional index (SFI), thermal heat hyperalgesia, mechanical hyperalgesia, and thermographic evaluation were used as analyses. The evaluations were performed preoperatively and 7, 14, 21, and 28 days after the initial injury analyzed by two-way analysis of variance (ANOVA) for mixed models followed by the Bonferroni post-test. All groups except sham and naive presented an SFI compatible with severe peripheral nerve injury on the 7th day of evaluation. The PBM group presented better results in the SFI analysis (p < 0.001) on the 21st postoperative day compared to the control group. This benefit was maintained when compared to the Simvastatin (p < 0.001) and PBM/Simv groups (p < 0.01). The results of the thermal and mechanical hyperalgesia and thermography analyses were not significant (p > 0.05). The obtained results showed that PBM alone was more effective compared to Simvastatin alone or PBM combined with Simvastatin for sciatic nerve injury in mice.

Comparação de diferentes comprimentos de onda do laser de baixa potência no sóleo de ratos Wistar após lesão nervosa

RESUMO Os músculos esqueléticos podem ser afetados por lesões do sistema nervoso periférico, levando a fraqueza e atrofia muscular. Na tentativa de recuperar a funcionalidade dos músculos, existem vários recursos terapêuticos utilizados, dentre os quais o laser de baixa potência (LBP). Este estudo comparou o efeito do LBP em dois comprimentos de onda (660 nm e 830 nm), em características morfológicas do tecido muscular após axonotmese de nervos isquiáticos de ratos Wistar. Para tanto, foram utilizados 32 ratos Wistar, divididos em quatro grupos, sendo G1 (controle), G2 (lesão), G3 (lesão e tratamento com LBP de 660 nm) e G4 (lesão e tratamento com LBP de 830 nm). Os animais de G2, G3 e G4 foram submetidos à lesão do nervo isquiático e, três dias após a lesão, G3 e G4 realizaram tratamento com LBP de 660 nm e 830 nm, respectivamente. Após o tratamento, todos os animais foram eutanasiados e os músculos sóleos coletados para confecção das lâminas histológicas, visando a realização de análises morfológicas do tecido. Constatou-se que os animais submetidos à lesão sofreram alterações morfológicas na fibra, resultando em sua atrofia. Foi percebido também que o LBP com comprimento de onda de 830 nm apresentou ligeiros sinais de recuperação das características morfométricas analisadas.

Effect of Low-Level Laser Therapy and Strength Training Protocol on Hand Grip by Dynamometry

Introduction: The purpose of this study was to investigate the effect of low-level laser therapy (LLLT) - 660 nm and 904 nm - before grip strength protocol in healthy subjects. Methods: The study included 45 healthy volunteers with an average age of 22.7 (±1.4) years, subdivided into the following groups, control group: grip strength training associated with placebo LLLT; 660 nm group: LLLT (660 nm, 20 J/cm², power of 30 mW, and beam area of 0.06 cm², continuous, energy 1.2 J, and exposure time 40 seconds per point) before grip strength training and 904 nm group: LLLT (904 nm, 10 J/cm², peak power of 70 W and 0.13 cm² beam area, with pulsed beam 9.500 Hz and 30 seconds of exposure time per point and emitted energy 1.2 J) before grip strength training. The LLLT was timed to contact 10 points located in the region of the superficial and deep flexor muscles of the fingers, with a total energy of 12.0 J per session. For the strength training protocol, the volunteer exercised their fingers with the dominant hand on a small table, elbow flexed at 90°, forearm in neutral, using a light extension handle. The Oxford protocol was performed during four weeks. The grip strength was assessed using a dynamometer (Jamar™). The data were evaluated by the analysis of variance (ANOVA) statistical method. Results: In the comparison of intragroup evaluation, only the 904 nm group showed a difference compared to the baseline assessment after 4 weeks (P < 0.05), in the final intergroup evaluation, a difference was observed in the comparison between the control and 904 nm groups Conclusion: In conclusion, LLLT (904 nm) applied before resistance training was effective in gaining grip strength when compared to LLLT (660 nm) and isolated strength training after 4 weeks.

Efficacy of low-level laser therapy associated to orthoses for patients with carpal tunnel syndrome: A randomized single-blinded controlled trial

OBJECTIVE

Compare the efficacy of orthoses and patient education with and without the addition to Low-Level Laser Therapy (LLLT - 660 nm, 30 mW, a continuous regime and bean area of 0.06 cm2). The laser irradiation was delivered with the fluency of 10J/cm2 in patients with mild and moderate Carpal Tunnel Syndrome (CTS).

METHODS

48 patients were randomized and 30 finished the protocol (a sample loss of 37.5%), 90% female and 10% males. Randomization was applied to allocate the patients in each one of the groups, with association or not to LLLT (group orthoses or LLLT and orthoses). All of them were submitted to ergonomic home orientations. The short-term symptoms and function outcome were assessed through: Boston Carpal Tunnel Questionnaire (BCTQ) - Severity of Symptoms (SS) Functional Score (FS). Pain (VAS), Semmes-Weinstein monofilaments, 2PD and pinch strength was used for characterization of the sample. Most of the participants were women, over 4th decade enrolled on heavy hand duties occupations, right-handed, 66.7% affected on dominant hand, without alterations in sensory median nerve thresholds or pinch strength.

RESULTS

Both groups showed a reduction of total BCTQ score and its subdomains after six weeks, with significant difference (p< 0.05), comparing to baseline. No significant difference was found between groups. A Minimal clinical change was observed after the intervention in 92.3% of participants for BCTQ subdomain severity of symptoms at individual comparison for LLLT and orthoses group and 76.5% for the orthoses group, demonstrating clinical relevance. Effect size Cohen's index was moderate for the severity of symptoms.

CONCLUSION

LLLT in association to orthoses and ergonomic orientation seems to be effective in short-term symptoms relieve for patients with mild and moderate CTS.

Efeito da associação da laserterapia com a natação no reparo morfológico do nervo isquiático e na recuperação funcional de ratos submetidos à axonotmese

RESUMO As lesões de nervos periféricos ocorrem frequentemente e, de modo geral, causam perda funcional impactando de forma negativa na vida do paciente. O objetivo do estudo foi verificar a eficiência da associação da laserterapia e natação em ratos acometidos por axonotmeses. A amostra foi composta por 50 ratos da linhagem Wistar. Foram divididos em 5 grupos, sendo: grupo controle (GC); grupo controle cirúrgico (GCC); grupo experimental laser (GEL); grupo experimental natação (GEN) e grupo experimental laser associado à natação (GELAN). O nervo foi esmagado em um segmento de 5 mm de comprimento próximo a trifurcação do nervo isquiático, feito com uma pinça durante 60 segundos. Foi utilizado o laser infravermelho AsGa (904 nm) com energia irradiada de 0,4 J na primeira semana, 0,8 J na segunda semana e 1,2 J na terceira e quarta semana. Para avaliação funcional (IFC), os animais foram imobilizados, e a região plantar das patas foram pintadas com tinta de carimbo. Esse procedimento foi repetido duas vezes com cada animal. Foi realizada a morfometria (áreas, diâmetros e espessuras das fibras, axônios e bainha de mielina) dos nervos com mensuração de 220 fibras por animal de cada grupo. Pudemos observar que os grupos GEL e GEN, em todas as variáveis morfométricas estudadas, obtiveram os melhores resultados, quando comparados com os outros grupos (GC, GCC e GELAN), mas não apresentou diferença estatisticamente significante entre eles. Na análise funcional observou-se que o grupo GELAN obteve o melhor resultado quando comparado com os outros grupos (GCC, GEL e GEN) e quando comparados os grupos GEL e GEN entre eles não houve diferença estatisticamente significante. A conclusão foi que os grupos GEL e GEN obtiveram os melhores resultados morfométricos, enquanto o GELAN apresentou o melhor resultado funcional. Portanto, pode-se concluir que a associação destes recursos favoreceu a recuperação funcional desses animais.