Analysis of the energy density variation of low-level laser therapy on crushed sciatic nerve of rats: morphological, quantitative and morphometric study

• Grant number: 14/22360-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): January 01, 2015
• Effective date (End): December 31, 2015
• Field of knowledge: Biological Sciences - Morphology - Anatomy
• Principal Investigator: Fernando José Dias
• Grantee: Eduardo Keiske Matsuda Ziago
• Host Institution: Faculdade de Odontologia de Ribeirão Preto (FORP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Recently an alternative treatment widely used in the repair of peripheral nerve tissue is low-level laser therapy (LLLT), but the physical parameters used are varied between studies. This project aims to evaluate 3 energy densities used in the application of LLLT in the treatment of lesions in peripheral nerves, using the crush injury for rat sciatic nerve (15 kgf, 5.2 MPa, 10 min). It will be used 35 Wistar rats (B, 200-250 g) divided into 5 groups (n = 7): GC - control; GLe - injured nerve without treatment; GL4 - injured nerve and treated with 4 J/cm2 of LLLT; GL10 - injured nerve and treated with 10 J/cm2 LLLT; and GL50 - injured nerve and treated with 50 J/cm2 LLLT. The animals will be sacrificed 2 weeks after the injury by anesthetic overdose (Ketamine / Xylazine - 150/10 mg / kg), the sciatic nerve samples will be obtained. The material obtained will be fixed (4% PFA), included in Leica® historesin, sliced (3 µm), mounted on slides and stained with Sudan black and neutral red method for historesin. After staining the slides will be photomicrographed and them will be performed the morphological, quantitative (myelin density and density of blood capillaries) and morphometric analysis (maximum and minimum diameters of nerve fibers axon diameter and G-ratio of myelin thickness) with the use of the "ImageJ" software and statistical analysis to compare the results among the groups.