Luteolin (LU) is a widely distributed flavonoid with multitarget effects. The objective of this study was to determine whether LU could reduce the ischemia-reperfusion injury of the spinal cord (SCII) in a rat model. Forty-eight rats were divided into four groups: sham, SCII, SCII+L-LU (50 mg/kg), and SCII+H-LU (100 mg/kg). Abdominal aortic occlusion was carried out for 40 min in all groups. Hindlimb motor functions were evaluated using the Tarlov scoring system. Nissl and terminal deoxynucleotidyl transferase-mediated dUTP biotin nick end labeling (TUNEL) staining were used to detect cell survival and apoptosis in the spinal cord. Spinal cord samples were taken for determination of malondialdehyde, xanthine oxidase, superoxide dismutase, and glutathione peroxidase activities. The levels of tumor necrosis factor-α, interleukin (IL)-1β, and IL-18 were assessed using ELISA kits to examine the inflammatory responses in the spinal cord. Western blot analysis was used to examine the expression of nuclear factor erythroid 2-related factor (Nrf2) and nod-like receptor pyrin domain-containing 3 protein (NLRP3) levels. We found that LU pretreatment significantly improved the locomotor function of rats after SCII, increased neuron survival, and inhibited apoptosis in the spinal cord. Furthermore, the oxidative stress and inflammatory response were significantly suppressed upon treatment with LU. Finally, LU upregulated Nrf2 levels and downregulated NLRP3 protein expression in SCII tissues. Thus, LU exhibited a neuroprotective effect following SCII by alleviating oxidative stress and inhibiting inflammatory responses and cell apoptosis. The possible mechanism may be related to the activation of Nrf2 and inhibition of NLRP3 inflammasome pathway.
Keywords: apoptosis; inflammatory responses; ischemia-reperfusion injury of the spinal cord; luteolin; oxidative stress.