This study aimed at evaluating the effects of red and blue light-emitting diodes (LED) and low-level laser (LLL) on the regeneration of the transected sciatic nerve after an end-to-end neurorrhaphy in rabbits. Forty healthy mature male New Zealand rabbits were randomly assigned into four experimental groups: control, LLL (680 nm), red LED (650 nm), and blue LED (450 nm). All animals underwent the right sciatic nerve neurotmesis injury under general anesthesia and end-to-end anastomosis. The phototherapy was initiated on the first postoperative day and lasted for 14 consecutive days at the same time of the day. On the30th day post-surgery, the animals whose sciatic nerves were harvested for histopathological analysis were euthanized. The nerves were analyzed and quantified the following findings: Schwann cells, large myelinic axons, and neurons. In the LLL group, as compared to other groups, an increase in thenumber of all analyzed aspects was observed with significance level (P < 0.05). This finding suggests that postoperative LLL irradiation was able to accelerate and potentialize the peripheral nerve regeneration process in rabbits within 14 days of irradiation.

82 patients with traumas of peripheral nervous trunks (middle, ulnar, radial, tibular and tibial nerves) were investigated, including 44 persons with neuroapraxia of those trunks and 38 with axonotmesis. It was established that the patients with traumas of peripheral nervous trunks showed the presence of inflammatory process and sensitization of the body which was exposed in the reaction of precipitation at C-reactive protein with the increase of the content of serum glycoides and total nonspecific immunuglobulin E in blood serum. The investigated patients showed also decrease in nonspecific resistance of organism and change in immune status. All the above-referred shifts were more expressed at axonotmesis of peripheral nervous trunks. Rehabilitation with the use of Kumisi therapeutic mud and electro magneto field of millimeter range resulted decrease of inflammation process and body sensitization in patients with traumas of peripheral nervous trunks almost to disappearance of inflammation process and body sensitization. Such rehabilitation increased nonspecific resistance, normalized the indices of immune reactivity. The above-referred positive shifts were comparatively well expressed at neuroapraxia of peripheral nervous trunks.

OBJECTIVE:This pilot double-blind randomized study evaluated the efficacy of 780-nm laser phototherapy on the acceleration of axonal growth and regeneration after peripheral nerve reconstruction by polyglycolic acid (PGA) neurotube.

BACKGROUND DATA:The use of a guiding tube for the reconstruction of segmental loss of injured peripheral nerve has some advantages over the regular nerve grafting procedure. Experimental studies have shown that laser phototherapy is effective in influencing nerve regeneration.

METHODS:The right sciatic nerve was transected, and a 0.5-cm nerve segment was removed in 20 rats. A neurotube was placed between the proximal and the distal parts of the nerve for reconnection of nerve defect. Ten of 20 rats received post-operative, transcutaneous, 200-mW, 780-nm laser irradiation for 14 consecutive days to the corresponding segments of the spinal cord (15 min) and to the reconstructed nerve (15 min).

RESULTS:At 3 months after surgery, positive somato-sensory evoked responses were found in 70% of the irradiated rats (p = 0.015), compared to 30% of the non-irradiated rats. The Sciatic Functional Index in the irradiated group was higher than in the non-irradiated group (p<0.05). Morphologically, the nerves were completely reconnected in both groups, but the laser-treated group showed an increased total number of myelinated axons.

CONCLUSION:The results of this study suggest that postoperative 780-nm laser phototherapy enhances the regenerative process of the peripheral nerve after reconnection of the nerve defect using a PGA neurotube.

SCOPE:Recent findings indicate that ketogenic diet is neuroprotective and electrical stimulation can improve functional recovery from peripheral nerve injury. However, it is not clear whether ketogenic diet and electrical stimulation play synergistical role in the peripheral nerve recovery following injury.

METHODS AND RESULTS:We used ketogenic diet consisting of 3:1 ratio of fat to carbohydrate+protein and coupled it with electrical stimulation treatment in a rat model of peripheral nerve crush injury. Neuromuscular recovery was evaluated by electromyography, and axonal regeneration and myelination by histological methods. We also investigated the effects on IGF-1 and IGF-1 receptor expression in peripheral nerve tissue, pre- and post-nerve injury. Combination of ketogenic diet and electrical stimulation synergistically increased muscle force in biceps femoris and gluteus maximus and prevented development of hypersensitivity in biceps femoris. It promoted peripheral nerve regeneration by increasing total axons, axons density, and axonal diameter, as well as myelin thickness and axon/fiber ratio. These effects were due to modulation of IGF system as the treatment expression of IGF-1 and IGF-1 receptor in regenerated nerve tissue.

CONCLUSION:Our results establish that ketogenic diet and electrical stimulation promote peripheral nerve regeneration. Patients recovering from peripheral nerve injury may benefit from this combinational approach. This article is protected by copyright. All rights reserved.

OBJECT:This review summarizes the continuous study of low-power laser radiation treatment of a severely injured peripheral nerve. Laser phototherapy was applied as a supportive factor for accelerating and enhancing axonal growth and regeneration after injury or a reconstructive peripheral nerve procedure. In nerve cell cultures, laser phototherapy was used to stimulate activation of nerve cells.

METHODS:Low-power laser radiation was used for treatment of peripheral nerve injury using a rat sciatic nerve model after crush injury, neurorrhaphy, or neurotube reconstruction. Nerve cell growth and axonal sprouting were investigated using laser phototherapy on embryonic rat brain cultures. The outcome in animal studies facilitated a clinical double-blind, placebo-controlled, randomized study that measured the effectiveness of 780-nm laser phototherapy on patients suffering from incomplete peripheral nerve injuries for 6 months to several years.

RESULTS:Animal studies showed that laser phototherapy has an immediate protective effect, maintains functional activity of the injured nerve, decreases scar tissue formation at the injury site, decreases degeneration in corresponding motor neurons of the spinal cord, and significantly increases axonal growth and myelinization. In cell cultures, laser irradiation accelerates migration, nerve cell growth, and fiber sprouting. A pilot clinical double-blind, placebocontrolled, randomized study showed that in patients with incomplete long-term peripheral nerve injury, 780-nm laser radiation can progressively improve peripheral nerve function, which leads to significant functional recovery.

CONCLUSIONS:Using 780-nm laser phototherapy accelerates and enhances axonal growth and regeneration after injury or a reconstructive peripheral nerve procedure. Laser activation of nerve cells, their growth, and axonal sprouting can be considered as potential treatment of neuronal injury. Animal and clinical studies show the promoting action of phototherapy on peripheral nerve regeneration, making it possible to suggest that the time for broader clinical trials has arrived.