Effects of γ-oryzanol on motor function in a spinal cord injury model

Spinal cord injury (SCI) is caused by disease or trauma and results in a partial or complete loss of motor or sensory function below the injury level. Most patients with SCI are young, and long-term disability imposes both psychological and financial burdens. Rice is the most abundant source of γ-oryzanol, which exhibits both antioxidant and anti-inflammatory properties. γ-Oryzanol has been shown to cross the blood-brain barrier in an intact form and have beneficial effects on brain function. To the best of our knowledge, this is the first study to report the effect of γ-oryzanol on motor function recovery in mice after SCI.

Mice were randomly divided into three groups: the sham group, the injury group, and the γ-oryzanol-treated group that received an intraperitoneal γ-oryzanol (100 mg/kg) injection every 2 days for 42 days after SCI. The effect of γ-oryzanol was assessed through various approaches. Behavioral tests were performed using Basso mouse scale scores and gait analysis. Hematoxylin and eosin staining, Luxol fast blue staining, magnetic resonance imaging ,and immunofluorescence staining were used to observe the lesion area changes, demyelination, axonal regeneration, and scar tissue formation. The levels of inflammatory cytokines in the peripheral blood of mice were assessed by enzyme-linked immunosorbent assay.

Behavioral tests showed that γ-oryzanol treatment improved gait following SCI. Pathological examination revealed that demyelination at the site of injury improved with γ-oryzanol treatment and was accompanied by the retention of axons associated with motor function and reduced scarring. Additionally, γ-oryzanol treatment decreased the serum levels of pro-inflammatory factors.

Studies have shown that γ-oryzanol promotes motor function recovery in mice after SCI. Therefore, γ-oryzanol might be the latent target for SCI therapy.