Efeito da Terapia Laser de Baixa Intensidade em modelo experimental após lesão do nervo ciático avaliados por meio da espectroscopia Raman

Abstract

Peripheral nerve injury can cause various impairment, especially morphofunctional, and the regeneration process of this tissue occurs slowly. A low-level laser therapy (LLLT) provides anti-inflammatory, analgesic and especially nerve tissue regeneration effects. The objective of this study was to evaluate biomolecular alterations by means of Raman Spectroscopy (RE) in the experimental model of sciatic nerve injury after low-level laser therapy. Sixty-four Wistar rats, all submitted to right crush injury, were divided into four intervention groups (Control 1, Control 2, laser 660 nm and laser 808 nm), subdivided into two stages (14 and 21 days), totaling eight groups of eight animals each. All groups underwent a painful sensitivity test and the Functional Science Index (IFC), respectively in the periods: preoperative; and on the first, seventh, fourteenth and twenty-first postoperative days (POD), this only for the 21-day group. Raman spectra were captured at three different points of the nerve, with a spectral resolution of 2 cm -1, in the spectral range of 1000-4000 cm -1, to identify the characteristics of the tissue used. All animals include sensory deficit on the right side after sciatic nerve injury. Principal component analysis (PCA) was observed in the biochemical composition of the nerve, with evidence of sphingolipids, phospholipids, glycoproteins. Higher concentration of myelin sheath components is noted in active groups with TLBI. SFI showed that all groups that were submitted to sciatic nerve injury had gait impairment, with improvement only after 14 days, the Laser group 660 nm presenting the best recovery. Raman spectroscopy was capable of identify biochemical changes from differents groups, indicating better recovery of peripheral nerve injury after LLLT, with proliferation of Schwann cells and myelin sheath reconstitution.