Neural mobilization: molecular and behavioral assessment in rats after induction of neuropathic pain.

Author(s)

Fabio Martinez dos Santos

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2015-07-28

Examining board members

Marucia Chacur; Tabajara de Oliveira Gonzalez; Marcelo Betti Mascaro; Rosana de Lima Pagano; Fabiano Politti

• Advisor: Marucia Chacur

Abstract

Neural mobilization technique (MOB) is a noninvasive method that demonstrated to be effective in reducing pain sensitivity in both clinical and research study. The present study aims to examine the effects of MOB in locomotors dysfunction, muscle strength, morphological changes in sciatic nerve and molecular changes induced by chronic constriction (CCI) of the sciatic nerve in Wistar rats. To analyze locomotors dysfunction we used the Sciatic nerve functional index (SFI). To analyze muscle strength, was used Biopac System. The nerve morphology was analyzed using electron microscopy and molecular changes through western blot assays. After MOB treatments, animals were euthanized and tissues such as, sciatic nerve, the posterior root ganglions (DRG L4-L6) and substance periaqueductal gray (PAG) were removed. The DRG were processed by western blot for detection of substance P (SP), transient receptor potential vanilloid type I (TRPV1) and opioids receptors (MOR, DOR, KOR). Regarding PAG, we analyze only opioids receptors. Our results demonstrated a full reversal of locomotors dysfunction-induced by CCI after MOB treatment and an increase of 172% on maximal tetanic muscle strength in animals treated with MOB when compared to the CCI group. Our studies on photomicrography of sciatic nerve showed an intense Wallerian degeneration process in CCI animals and an intense regeneration of myelinated fibers. In western blot assays, we identified, in DRG, an increase of SP and TRPV1 expression after CCI and a decrease of optical density after MOB treatment. Regarding opioid receptor, we did not identify statistical changes on DOR and KOR in DRG, but we observed an increased expression of MOR in CCI after MOB treatment group. In PAG analyses, we observed a decrease in DOR and KOR expression after MOB treatment when compare with CCI animals. On the other hand, we did not identify any changes on MOR receptor. Based on our findings, we suggest that treatment with neural mobilization technique it is able to reverses the locomotors dysfunction and increases maximum tetanic force of the tibialis anterior muscle after CCI. Furthermore, the same treatment was also able to induce a severe regeneration in the sciatic nerve after treatment. Still, we can suggest an important role of MOB in modulating SP and TRPV 1 expression. We suggest that antinociceptive effect induced by MOB technique can also be involved with descending pain inhibitory system resulting in inhibition of the transmission of afferent nociceptive stimulus and thereby reducing neuropathic pain because of the influence of MOB opioids in the PAG. (AU)

• FAPESP's process: 12/05840-4 - Neural Mobilization: molecular and behavioral assessment in rats after induction of neuropathic pain
• Grantee: Fabio Martinez dos Santos
• Support Opportunities: Scholarships in Brazil - Doctorate