Opuntia ficus-indica waste, a source of bioactive Compounds, in counteractive neurodegenerative Process in zebrafish larvae

Spinal cord injury (SCI) triggers a complex cascade of primary and secondary damage, characterized by oxidative stress, inflammation, and neurodegeneration, which challenge recovery and functional regeneration. Natural compounds, particularly flavonoids, have emerged as promising neuroprotective agents due to their antioxidant and anti-inflammatory properties. This study aimed to evaluate the therapeutic potential of a flavonoid-rich hydroalcoholic extract derived from unripe Opuntia ficusindica fruits in promoting recovery from SCI using zebrafish larvae as a model organism. The extract’s chemical composition was characterized, revealing a high concentration of bioactive flavonoids. To investigate its effects on SCI recovery, zebrafish larvae were subjected to a standardized spinal cord transection model and treated under three experimental conditions: continuous, preventive, and curative. Recovery outcomes were assessed through behavioral analysis, molecular markers of inflammation and oxidative stress, and expression levels of neurogenesis-associated genes, including components of the Hedgehog signaling pathway. Results showed that the flavonoid-rich extract significantly reduced proinflammatory cytokines (IL-1β, IL-8, TNF-α) and enhanced antioxidant defense mechanisms, as evidenced by increased Sod1 expression. The extract also promoted glial bridge formation and upregulated Shh, Nestin, and Ngn1 genes, key markers associated with neuronal regeneration and differentiation. Behavioral assessments demonstrated improved locomotor recovery in the continuous and preventive treatment groups compared to the curative group and untreated controls. In conclusion, this study highlights the neuroprotective and regenerative potential of Opuntia ficus-indica flavonoids in mitigating SCI-induced damage. Zebrafish larvae provided an effective and translational model to explore molecular pathways underlying SCI recovery, supporting the application of natural compounds as innovative therapeutic strategies for neuroregenerative medicine.