Effects of 660 nm Low Level Laser Therapy on Neuropathic Pain Relief Following Chronic Constriction Injury in Rat Sciatic Nerve

Background: Different types of pain such as neuropathic pain (NP) are still challengeable conditions in medical disciplines. Neuropathy leads to medical, social and economic problems for the patient, thus various therapies are being used to treat or reduce it. There are numerous studies mainly focused on the role of reactive oxygen species (ROS) and oxidative stress for NP. Recently, Low level Laser Therapy (LLLT) has been used in certain areas of medicine and neuro-rehabilitation. Chronic constriction injury (CCI) is a well-known model for neuropathic pain studies. Objectives: The present research was designed to find the effects of 660 wave length LLLT on injured sciatic nerve. Materials and Methods: Twenty Wistar adult male rats (230 – 320 g) were used in this study. The animals were randomly divided into three groups (n = 10). To induce neuropathic pain for sciatic nerve, CCI technique was used. Low Level Laser of 660nm was used for consecutive two weeks. Thermal and mechanical hyperalgesia were performed before and after the operation on days 7 and 14 respectively. Paw withdrawal thresholds were also evaluated. Results: Our results showed that CCI decreased the pain threshold; whereas, LLLT of 660nm wave length for two weeks increased the mechanical and thermal thresholds significantly. Comparison of the mechanical and thermal thresholds showed significant therapeutic effects of LLLT in trial groups than control. Conclusions: Although our results showed the therapeutic effects of LLLT on NP and might be used for clinical application in neuropathic cases; more future clinical studies are needed.