Neuroprotective Effect of Fructus Ligustri Lucidi in Spinal Cord Neuron Injury during H2O2-Mediated Oxidative Stress

Abstract

Oxidative stress-induced neuronal damage is a significant factor contributing to spinal cord injury. Although previous research has shown that Fructus Ligustri Lucidi (FLL) has neuroprotective benefits in SH-SY5Y, BV2, and PC12 cells, its impact on primary spinal cord neurons, which more accurately reflect the characteristics of central nervous system neurons, remains unexplored. This research investigated how FLL can protect rat primary spinal cord neurons from injury triggered by hydrogen peroxide (H2O2)-mediated oxidative stress. Cell viability, generation of reactive oxygen species (ROS), upregulation of inducible nitric oxide synthase (iNOS), activation of the Nrf2/HO-1 antioxidant pathway, and mitochondrial superoxide were assessed. Rat primary spinal cord neurons were not adversely affected by concentrations of FLL extract up to 100 μg/mL. Furthermore, FLL extract showed a significant protective effect against H2O2-induced neuronal toxicity at 10–100 μg/mL. Fluorescence-activated cell sorting analysis revealed that FLL extract inhibited H2O2-induced ROS generation in a dose-dependent manner. Immunocytochemistry and gene expression analysis confirmed that FLL extract reduced the overexpression of iNOS induced by H2O2 and enhanced the stimulation of the Nrf2/HO-1 pathway, crucial for antioxidant responses. In conclusion, FLL extract demonstrated neuroprotective effects on rat primary spinal cord neurons against the oxidative stress induced by H2O2. FLL extract effectively preserved cell viability, reduced ROS generation, suppressed iNOS overexpression, and activated the Nrf2/HO-1 antioxidant pathway. These results highlight the capacity of FLL extract as a neuroprotective agent against oxidative stress-related spinal neuron damage.