Histological analysis of low-intensity laser therapy effects in peripheral nerve regeneration in Wistar rats

Cibele Nazaré Da Silva Câmara,Edvaldo Lima Silveira,Roberto Waldesmand Farias Pontes,Marcus Vinicius Henriques Brito,Diego Sá Guimarães Da Silva,Vivian Roberta Ferreira Simões

doi:10.1590/s0102-86502011000100004

Cibele Nazaré Da Silva Câmara, Edvaldo Lima Silveira + Show 4 more

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https://doi.org/10.1590/s0102-86502011000100004

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Abstract

Analyze the influence of low-intensity laser therapy in the sciatic nerve regeneration of rats submitted to controlled crush through histological analysis. Were used 20 Wistar rats, to analyze the influence of low-intensity laser therapy in the sciatic nerve regeneration, where the injury of the type axonotmesis was induced by a haemostatic clamp Crile (2nd level of the rack). The animals were randomly distributed in 2 groups. Control group (CG n = 10) and Laser group (LG n = 10). These were subdivided in 2 subgroups each, according to the euthanasia period: (CG14 - n = 5 and CG21 - n = 5) and (LG14 - n = 5 and LG21 - n = 5). At the end of treatment, the samples were removed and prepared for histological analysis, where were analyzed and quantified the following findings: Schwann cells, myelinic axons with large diameter and neurons. In the groups submitted to low-intensity laser therapy, were observed an increase in the number of all analyzed aspects with significance level. The irradiation with low intensity laser (904nm) influenced positively the regeneration of the sciatic nerve in Wistar rats after being injured by crush (axonotmesis), becoming the nerve recovery more rapid and efficient.

Highlights

IntroductionPeripheral nerves are structures frequently affected by traumatic lesions, as total or partial crush, compression, stretch, avulsion and section that cause the interruption of the transmission of nerve impulses, the reduction or lost of sensitivity and motility in the innerved area[1].According to Pachioni et al.[2] this type of lesion if not adequately treated may provoke a significant deficit, with damages in the quality of life of patients, and to the state system in cases of premature retirement due to functional incapacity.numerous studies have searched for the optimization of the regeneration of peripheral nerves utilizing different techniques, always aiming to abbreviate the period of recovery of the injured nerve[3,4].the model of crush lesion has been adopted by several authors that emphasize the fact that the crush preserves, at least in part, the nerve structure, facilitating its regeneration, and for not demonstrating the necessity of realizing a suture, what implicates in previous training in microsurgical techniques and the availability of adequate instrumental and material, in general, with high cost[1].Studies on molecular biology have sustained that the laser therapy increases the rates of nerve regeneration, reinnervation and neuronal survival after the rupture of axons[5].The molecular base that would justify the effectiveness of the laser therapy on the nerve regeneration has not been clear yet
Among several generators of laser therapy, we may highlight Arsenate-Gallium Laser (As-Ga), which is already known to accelerate the recovery of peripheral nerves[7]
The objective of this study was to analyze the influence of Low-intensity laser therapy in the sciatic nerve regeneration of rats submitted to controlled crush through histological analysis

Summary

Introduction

Peripheral nerves are structures frequently affected by traumatic lesions, as total or partial crush, compression, stretch, avulsion and section that cause the interruption of the transmission of nerve impulses, the reduction or lost of sensitivity and motility in the innerved area[1].According to Pachioni et al.[2] this type of lesion if not adequately treated may provoke a significant deficit, with damages in the quality of life of patients, and to the state system in cases of premature retirement due to functional incapacity.numerous studies have searched for the optimization of the regeneration of peripheral nerves utilizing different techniques, always aiming to abbreviate the period of recovery of the injured nerve[3,4].the model of crush lesion has been adopted by several authors that emphasize the fact that the crush preserves, at least in part, the nerve structure, facilitating its regeneration, and for not demonstrating the necessity of realizing a suture, what implicates in previous training in microsurgical techniques and the availability of adequate instrumental and material, in general, with high cost[1].Studies on molecular biology have sustained that the laser therapy increases the rates of nerve regeneration, reinnervation and neuronal survival after the rupture of axons[5].The molecular base that would justify the effectiveness of the laser therapy on the nerve regeneration has not been clear yet. The model of crush lesion has been adopted by several authors that emphasize the fact that the crush preserves, at least in part, the nerve structure, facilitating its regeneration, and for not demonstrating the necessity of realizing a suture, what implicates in previous training in microsurgical techniques and the availability of adequate instrumental and material, in general, with high cost[1]. Studies suggest that low-intensity laser therapy improves function, accelerates regenerative process, and decreases inflammatory response in the nerve. It can promote a higher metabolism in neurons and a better ability to produce myelin[6]. The results can vary depending on the pattern of the lesion induced and the lasers range[8]

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