RESUMO
OBJECTIVE: Oxidative stress plays an important role in neuropathic pain (NP). Spinal manipulative therapy (SMT) can exert beneficial effects on pain outcomes in humans and in animal models. SMT can also modulate oxidative stress markers in both humans and animals. We aimed to determine the effect of Impulse®-assisted SMT (ISMT) on nociception and oxidative stress biomarkers in the spinal cords and sciatic nerves of rats with NP. METHODS: NP was induced by chronic constriction injury (CCI) of the sciatic nerve. Animals were randomly assigned to naive, sham (rats with sciatic nerve exposure but without ligatures), or CCI, with and without ISMT. ISMT was applied onto the skin area corresponding to the spinous process of L4-L5, three times per week for 2 weeks. Mechanical threshold, latency to paw withdrawal in response to thermal stimulus, and oxidative stress biomarkers in the spinal cord and sciatic nerve were the main outcomes evaluated. RESULTS: ISMT significantly increased mechanical threshold and withdrawal latency after CCI. In the spinal cord, ISMT prevented the increase of pro-oxidative superoxide anion generation and hydrogen peroxide levels. Lipid hydroperoxide levels both in the spinal cord and in the sciatic nerve were attenuated by ISMT. Total antioxidant capacity increased in the spinal cords and sciatic nerves of CCI rats with and without ISMT. CCI and ISMT did not significantly change the total thiol content of the spinal cord. CONCLUSIONS: Our findings suggest that reduced oxidative stress in the spinal cord and/or nerve may be an important mechanism underlying a therapeutic effect of SMT to manage NP nonpharmacologically.
