146 | Preventive effect of intranasal lemon-derived nanovesicles in a high-fat diet rat model of metabolic syndrome: modulation of anxiety-like behavior and survival signalling pathways

Cognitive dysfunction is a core feature of metabolic syndrome (MetS), associated with neuroinflammation and dysregulated neuronal signaling. High-fat diet (HFD) reliably models these brain alterations, influencing affective domains, and therefore represents a suitable platform for testing neuroprotective interventions. In this context, industrial lemon-derived nanovesicles (iLNVs) have recently stood out for their potent antioxidant and anti-inflammatory properties in preclinical models. In this study, we investigated the preventive potential of iLNVs on alterations induced by 12 weeks of HFD in a rat model of MetS. Rats fed either HFD or normal diet received daily intranasal iLNVs treatment alongside the dietary exposure to enhance brain delivery, and were compared with vehicle-treated HFD and normal-diet control groups. Cognitive and affective domains were assessed through behavioral paradigms sensitive to anxiety-like responses, including novelty-suppressed feeding (NSFT) and dark-light box tests (DWB). Ex-vivo molecular profiling by Western blot was performed on brain tissue to investigate survival-related signaling pathways. Our data showed that intranasal administration of iLNVs improved the HFD-induced anxiety phenotype, indicated by the reduced feeding latency in the NSFT and increased time spent in the light zone in DWB. Moreover, in normal-diet fed rats the iLNVs treatment induced a reduced feeding latency as well, accompanied by increased food consumption in the home cage. These findings suggest that iLNVs can modulate behavioral responses to mild stress by reducing anxiety and enhancing explorative motivation both in HFD-induced impairment and in physiological conditions. At the molecular level, iLNVs supplementation mitigated HFD-induced alterations in MAPK/ERK signaling, suggesting a mechanistic link between the restoration of survival related signaling and the observed reduced anxiety-like behavior. Consequently, intranasal iLNVs delivery could represent a promising nutraceutical approach for the prevention and treatment of affective dysfunctions associated with metabolic syndrome, but also for the amelioration of physiological response to stress.