Pain Medicine 2021 (May 16); pnab167
Francielle B O da Silva, BS, Maria do Carmo Q Santos, MS, Thaisla Cristiane Borella da Silva et. al.
Laboratório de Neurobiologia Comparada,
Departamento de Fisiologia,
Instituto de Ciências Básicas da Saúde,
Universidade Federal do Rio Grande do Sul,
Porto Alegre, Rio Grande, do Sul.
Objective: Oxidative stress plays an important role in neuropathic pain. Spinal manipulative therapy (SMT) can exert beneficial effects in pain outcomes in humans and 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 cord and sciatic nerve of rats with neuropathic pain (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) and CCI, with and without ISMT. ISMT was applied onto the skin area corresponding to the spinous process of L4-L5, 3 times/week, for 2 weeks. Mechanical threshold, latency to paw withdrawal to thermal stimulus and oxidative stress biomarkers in 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 cord and sciatic nerve 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 reduced oxidative stress in the spinal cord and/or nerve may be an important mechanism underlying a therapeutic effect of SMT to manage NP non-pharmacologically.
Keywords: Antinociception; Antioxidant; Pain; Pro-oxidant; spinal manipulation.