Eugenol promotes functional recovery and alleviates inflammation, oxidative stress, and neural apoptosis in a rat model of spinal cord injury.

Eugenol, a natural phenolic compound found in essential oils, shows a variety of remedial properties, while its effect on spinal cord injury (SCI) is still unknown.

To study the effects of Eugenol on SCI-related impairments in rats.

Rats received SCI or sham surgery were administered by oral gavage with Eugenol or physiological saline 6 hours following SCI and once a day for seven consecutive weeks. Basso, Beattie, Bresnahan (BBB) score and inclined plane test were used to assess locomotion function, while mechanical allodynia and thermal hyperalgesia were used to evaluate the withdrawal response to painful stimuli. Spinal cord water content was counted and permeability of the blood-spinal cord barrier was assessed by Evans blue extravasation. Serum tumor necrosis factor (TNF)-α, interleukin (IL)-1β, interleukin (IL)-6, nuclear factor (NF)-κB p65, superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), and glutathione peroxidase (GSH-Px) were determined by ELISA (enzyme-linked immunosorbent assay), while NF-κB p65, p38 mitogen-activated protein kinase (MAPK), inducible nitric oxide synthase (iNOS), and Caspase-3 in the spinal cord were detected by Western blot.

Eugenol markedly improved locomotor function and alleviated neuropathic pain, accompanied by decreased inflammation, oxidative stress, and neural apoptosis-associated molecules in the serum and injured spinal cord. Downregulated pathway molecules NF-κB and p38 MAPK were also found in the spinal cord.

These findings suggest that down-regulating NF-κB and MAPK signaling pathway may support the neuroprotective effect of Eugenol against traumatic SCI.