Neuroprotective Effects of Nigella sativa Oil against Dibutyl Phthalate-induced Neurotoxicity in Prefrontal Cortex of Wistar Rats

The prefrontal cortex regulates executive functions, including decision-making, emotion regulation, and behavior. Environmental toxicants like di-butyl phthalate (DBP), a commonly used plasticizer, have been implicated in oxidative stress and neuronal dysfunction. This research explored the protective role of Nigella sativa oil (NSO) against DBP-induced neurotoxicity in the prefrontal cortex of male Wistar rats. Forty rats were randomly assigned into five groups: control, NSO only (2 mL/kg b.w.), DBP only (500 mg/kg b.w.), DBP + NSO, and DBP withdrawal. Treatments were administered orally for 35 days, except the withdrawal group, which received DBP for 21 days followed by no treatment. Behavioral performance was evaluated using the open field test. Prefrontal cortex weights were recorded, and oxidative stress biomarkers, including malondialdehyde (MDA) and catalase, were assessed in tissue homogenates. Histological analysis was performed using cresyl violet staining. DBP administration caused significant reductions in body and brain weights, impaired exploratory behavior, increased MDA, reduced antioxidant enzyme activity, and induced neuronal degeneration. Co-administration of NSO preserved body and brain weights, improved behavioral outcomes, restored oxidative balance, and maintained normal neuronal architecture, while DBP withdrawal showed partial but incomplete recovery. These results demonstrated that NSO protected the neurons in the prefrontal cortex from the toxic effects of DBP. This was primarily due to its antioxidant action. Therefore, NSO can be considered a natural therapeutic agent against environmental neurotoxins.

Key Words: neurotoxicity, Nigella sativa oil, prefrontal cortex, oxidative stress