Low-level laser therapy, at 830 nm, for pain reduction in experimental model of rats with sciatica.
Injury and Physiotherapeutic Resource Study Laboratory, Western Paraná State University, Cascavel, PR, Brazil.
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.
Acta Cir Bras. 2011 Feb;26(1):12-18.
Histological analysis of low-intensity laser therapy effects in peripheral nerve regeneration in Wistar rats.
Câmara CN, Brito MV, Silveira EL, Silva DS, Simões VR, Pontes RW.
Department of Physiotherapy, UNAMA, Belem, PA, Brazil.
Purpose: Analyze the influence of low-intensity laser therapy in the sciatic nerve regeneration of rats submitted to controlled crush through histological analysis. Methods: 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. Results: In the groups submitted to low-intensity laser therapy, were observed an increase in the number of all analyzed aspects with significance level. Conclusion: 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.
In Vivo. 2004 Jul-Aug;18(4):489-95.
Effect of Ga-as laser on the regeneration of injured sciatic nerves in the rat.
Bae CS, Lim SC, Kim KY, Song CH, Pak S, Kim SG, Jang CH.
College of Veterinary Medicine, Biotechnology Research Institute, Chonnam National University, Gwangju, Korea.
Laser irradiation is one of the therapeutic methods for the recovery of degenerated peripheral nerves. The aim of the present study was to determine if low-power laser treatment stimulates the regeneration process of damaged nerves. A standardized crush to the sciatic nerve was applied to cause extensive axonal degeneration. After this procedure, low-power infrared laser irradiation was administered transcutaneously to the injured sciatic nerve, 3 minutes daily to each of four treatment groups for 1, 3, 5 and 7 weeks, respectively. A nerve conduction study was done, and a morphological assessment was performed using both light and electron microscopy. With trauma of the nerve, both amplitude of compound motor action potential and nerve conduction velocity decreased significantly compared to the pre-trauma state. Morphologically, the numbers of myelinated axons and degenerated axons were decreased and increased, respectively, compared with the control. Typical aspects were of onion skin-type lamellation, fragmentation, edematous swelling and rarefaction in the myelin sheath. All these parameters recovered almost to the level of the pre-trauma state with laser irradiation, in direct proportion to the time spent for treatment. These results suggest that low-power infrared laser irradiation can relieve the mechanical damage of sciatic nerves and stimulate the regeneration of peripheral nerves.