4057 Advances in Environmental Biology, 6(12): 4057-4061, 2012 ISSN 1995-0756 This is a refereed journal and all articles are professionally screened and reviewed ORIGINAL ARTICLE Corresponding Author Mohammad Ashrafzadeh Takhtfooladi, Department of Surgery, Faculty of Specialized Veterinary Science, Science and Research Branch, Islamic Azad University, Tehran, Iran. E-mail: dr_ashrafzadeh@yahoo.com Effects of Laser Therapy (680 nm) on Recovery of the Sciatic Nerve in Rabbits 1 Mohammad Ashrafzadeh Takhtfooladi, 2 Davood Sharifi, 3 Iraj Sohrabi Haghdost, 1 Gholamreza Abedi 1 Department of Surgery, Faculty of Specialized Veterinary Science, Science and Research Branch, Islamic Azad University, Tehran, Iran. 2 Department of Surgery & Radiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran. 3 Department of Pathology, Faculty of Specialized Veterinary Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran. Mohammad Ashrafzadeh Takhtfooladi, Davood Sharifi, Iraj Sohrabi Haghdost, Gholamreza Abedi: Effects of Laser Therapy (680 nm) on Recovery of the Sciatic Nerve in Rabbits ABSTRACT Peripheral nerve injuries are common, and there is no easily available formula for successful treatment. Incomplete injuries are most frequent. After complete axonal transection, the neuron undergoes a number of degenerative processes, followed by attempts at regeneration. Unfortunately, results of nerve repair to date have been no better than fair. Many evidence lines have shown that peripheral nerves regeneration may be accelerated by physical agents. Laser irradiation is one of the therapeutic methods for the recovery of degenerated peripheral nerves. The objective of this study was to investigate whether laser therapy (680 nm) could stimulate the healing process in the sciatic nerve regeneration in rabbits submitted to complete transection through histological analysis. Twenty adult white New Zealand male rabbits were used, where the injury of the type neurotmesis of the right sciatic nerve under general anesthesia (intramuscular ketamine/xylazine) was approximated using prolene 6-0. The rabbits were randomly distributed in 2 groups with 10 rabbits each. In group I, Arsenate of Gallium Laser with the extension of wave of 680 nm, 10 mW power with 1.0 J/cm 2 irradiation with 10 seconds for each Cm 2 , in the pulsed form. The laser therapy in group I was initiated on the post-surgical first day, where all the rabbits with application once a day for 14 days or 10 minutes each rabbit. Rabbits in group II not had given treatment (control group). The samples of transected nerves were collected and prepared of histological analysis on the 30 days. The histological aspect showed that in the injury site, blood vessels were more prevalent and thicker for group I than group II. Thick fibers with very thin myelin sheaths were prevalent in the injury site in both groups. Schwann cells with reactive appearance nuclei, characteristic of synthesis activity, as well as typical images of axonal sprouting were more prevalent on group I, while Wallerian degeneration was more evident on group II. Small-gauge fibers and thin myelin sheaths were prevalent, although thick fibers and thick myelin sheaths were also frequent on group II next to a large number of Schwann cells with reactive- appearance nucleus and images of axonal sprouting. In this site, Wallerian degeneration was not so evident for group I. This study suggests that postoperative laser irradiation (680 nm) was able to accelerate and potentialize the peripheral nerve regeneration process of rabbits. Key words: Laser Therapy, Nerve Regeneration, Sciatic. Introduction The regeneration and repair phase following nerve injury may last for many months. The human peripheral neuron’s capacity to initiate a regenerative response appears to persist for at least 12 months after injury, and a robust response can be elicited even after repeated injuries [1]. Many evidence lines have shown that peripheral nerves regeneration may be accelerated by physical agents. Laser therapy seems to be an efficient technique in peripheral nerve recovery, and its effectiveness has been shown over the years. A critical review of the literature [2] found that more than 80% of the experimental studies carried out so far on the use of laser therapy for promoting peripheral nerve repair led to a positive outcome in posttraumatic/ post-operative nerve recovery, thus pointing to this physical therapy tool as a very promising clinical approach for patients who suffered a nerve lesion. In contrast, there are conflicting results on the use of laser therapy. These results may be due to the lists of technical variables (in particular wavelength, doses, and types of radiation) that, if not properly adjusted, can reduce the success of any therapeutic procedure [2, 3]. Following the need to establish clinical protocols for