Efeito da terapia laser de baixa intensidade (808nm) no controle da dor neuropática em camundongos

Abstract

Pain, according to the International Association for the Study of Pain (IASP) can be defined as "an unpleasant sensory and emotional experience that is associated with actual or potential damage or described in terms of such damage". Lesions of the central or peripheral nervous system can lead to a special type of pain, called neuropathic pain. The methods used for the treatment of neuropathic pain injuries include medications, physical therapy, psychotherapy and anesthetics and neurosurgical procedures. Among the resources used by physiotherapists to low intensity laser therapy (LLLT) has been showing good results in controlling neuropathic pain. Because few studies and controversial data on the laser dosimetry in neuropathic pain judges is of great importance to research in establishing appropriate parameters for the application of this therapeutic resource. 50 mice of Swiss-albino strain were used, males weighing 25-30 grams. The experimental model of neuropathy was used by the partial sciatic nerve injury by chronic constriction surgery sciatic nerve (CCI). The animals were divided randomly into 5 groups: sham (GS) Group: Simulation of chronic constriction surgery sciatic nerve (CCI); control group (CG): induction of neuropathy by CCI surgery with application of laser off; laser therapy group 10 J / cm2 (GL10): induction of neuropathy by CCI surgery with application of LLLT (808 nm), with fluency of 10 J / cm2; Laser therapy group 20 J / cm2 (GL20): induction of neuropathy by CCI surgery with application of LLLT (808nm), with fluency of 20J / cm2; gupo laser therapy 40 J / cm2 (GL40): induction of neuropathy by CCI surgery with application of LLLT (808nm), with fluency of 40J / cm2. Pain treatment was performed by LLLT 3 times a week, every other day, in a ninety days period with different dosimetry (10 J / cm2, 20 J / cm2, 40J / cm). For nociceptive evaluations were used the Hot Plate Test for the thermal hyperalgesia and mechanical hyperalgesia and the Ralndall Selitto test. ELISA assay was used to quantify β-endorphin. The results showed that LLLT induced a significant increase in nociceptive threshold mainly in the groups using LLLT with higher fluence (20 J / cm2, 40 J / cm2), and demonstrate an increase in β-endorphin levels in the same groups. Thus we can conclude that LLLT significantly reduces neuropathic pain, being a mechanism of stimulation of β-endorphin.