Nervonic acid confers neuroprotection in a zebrafish model of diabetic neuropathy by promoting myelin repair and metabolic modulation

Introduction: Diabetic neuropathy (DN) is one of the most common and debilitating complications of type 2 diabetes mellitus (T2DM), yet effective therapeutic strategies remain limited. Nervonic acid (NA) is recognized for its neuroprotective and anti-inflammatory properties. However, its role in DN has not been fully elucidated. In this study, we investigated the protective effects of NA against T2DM-induced DN using a zebrafish model and explored the underlying molecular mechanisms. Methods: T2DM was induced in zebrafish larvae through a high-fat, high-glucose diet combined with a low dose of streptozotocin. Larvae were subsequently treated with NA at concentrations of 125, 250, or 500 μg/mL. Motor function, myelin integrity, neutrophil infiltration, and reactive oxygen species (ROS) levels were evaluated using fluorescence imaging and histological staining. Gene expression analysis was performed by quantitative real-time PCR. Metabolomics coupled with KEGG enrichment analysis was applied to identify NA-regulated metabolic pathways. Results: ) was upregulated, while pro-inflammatory cytokines were downregulated following NA treatment. Metabolomic profiling revealed that NA reversed diabetes-associated dysregulation in purine metabolism, energy metabolism, vitamin B6 pathways, and redox homeostasis. Key metabolites including guanosine monophosphate, adenosine triphosphate, pyridoxal 5'-phosphate, and L-glutathione were markedly restored toward normal levels. Discussion: These findings demonstrate that NA confers robust neuroprotection in DN by alleviating inflammation and oxidative stress, preserving neuronal structure and function, and reprogramming key metabolic pathways.