Neuroprotective effects of Olea europaea L. leaf extract on neuroinflammation and memory impairment induced by toluene and noise exposure: Assessing brain changes in rat

• Olive leaf extract protects against neuroinflammation. • Treated rats showed alleviated oxidative stress. • Olive leaf extract preserved brain histology. • OLE administration improved rat behavior and learning. • Promising potential for future pharmacological research. Our study aimed to investigate the impact of toluene and/or noise exposure on rat brains and assess the preventive effects of Olea europaea L. leaf extract (OLE) through biochemical, histopathologic analyses, behavior tests, and in silico study. Forty-eight male Wistar rats were randomly divided into eight groups: a control group, an OLE group, a noise-exposed group, a noise-exposed group treated with OLE, a toluene-exposed group, a toluene-exposed group treated with OLE, a co-exposed group to noise and toluene, and a co-exposed group to noise and toluene treated with OLE. OLE was orally administered at 40 mg/kg daily for six weeks. The results showed that noise and toluene exposure significantly disrupted brain tissue structure, causing oxidative damage, as evidenced by increased lipid peroxidation, decreased catalase and superoxide dismutase activities, and increased acetylcholinesterase (AChE) activity. However, OLE administration alleviated oxidative stress by restoring antioxidant biomarker levels, maintaining AChE close to normal, and preserving brain histology, while also improving rat behavior and learning. These findings suggest that OLE may protect brain tissue against simultaneous exposure to noise and toluene. Importantly, these results have significant implications for the prevention and treatment of neurotoxicity associated with exposure to toluene and noise, highlighting the potential practical applications of our research.