Laser Therapy and Pain-Related Behavior after Injury of the Inferior Alveolar Nerve: Possible Involvement of Neurotrophins

Author(s)

Martins, Daniel de Oliveira ^[1] ; dos Santos, Fabio Martinez ^{[2, 1]} ; de Oliveira, Mara Evany ^[1] ; de Britto, Luiz R. G. ^[3] ; Dias Lemos, Jose Benedito ^[4] ; Chacur, Marucia ^[1]

Affiliation

^[1] Univ Sao Paulo, Lab Funct Neuroanat Pain, Dept Anat, BR-05508000 Sao Paulo - Brazil

^[2] Univ Nove de Julho, Sao Paulo - Brazil

^[3] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05508000 Sao Paulo - Brazil

^[4] Univ Sao Paulo, Sch Dent, BR-05508000 Sao Paulo - Brazil

• Document type: Journal article
• Source: JOURNAL OF NEUROTRAUMA; v. 30, n. 6, p. 480-486, MAR 2013.
• Web of Science Citations: 5

Abstract

Nerve-related complications have been frequently reported in dental procedures, and a very frequent type of occurrence involves the inferior alveolar nerve (IAN). The nerve injury in humans often results in persistent pain accompanied by allodynia and hyperalgesia. In this investigation, we used an experimental IAN injury in rats, which was induced by a Crile hemostatic clamp, to evaluate the effects of laser therapy on nerve repair. We also studied the nociceptive behavior (von Frey hair test) before and after the injury and the behavioral effects of treatment with laser therapy (emitting a wavelength of 904 nm, output power of 70 Wpk, a spot area of similar to 0.1 cm(2), frequency of 9500 Hz, pulse time 60 ns and an energy density of 6 J/cm(2)). As neurotrophins are essential for the process of nerve regeneration, we used immunoblotting techniques to preliminarily examine the effects of laser therapy on the expression of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF). The injured animals treated with laser exhibited an improved nociceptive behavior. In irradiated animals, there was an enhanced expression of NGF (53%) and a decreased BDNF expression (40%) after laser therapy. These results indicate that BDNF plays a locally crucial role in pain-related behavior development after IAN injury, increasing after lesions (in parallel to the installation of pain behavior) and decreasing with laser therapy (in parallel to the improvement of pain behavior). On the other hand, NGF probably contributes to the repair of nerve tissue, in addition to improving the pain-related behavior. (AU)

• FAPESP's process: 11/22268-0 - Laser application in pain control and tissue stimulation: from basic research to clinical application
• Grantee: Marucia Chacur
• Support Opportunities: Regular Research Grants
• FAPESP's process: 10/20026-6 - Use of low-level laser and mechanisms in molecular and cellular repair process in peripheral nervous system
• Grantee: Daniel de Oliveira Martins
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)