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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.

In many occupational settings, workers are frequently exposed to toluene and noise. However, the individual and combined effects of these exposures on the cardiovascular system have not been fully elucidated. Therefore, this study aimed to investigate the impact of simultaneous exposure to toluene and noise on the rat heart, while also evaluating the potential preventive effect of olive leaf extract (OLE). Forty-eight male Wistar rats were randomly assigned to eight groups (n = 6/group): control group (C), control group that received OLE (C + OLE), group exposed to noise (N), group exposed to noise and receiving OLE (N + OLE), group exposed to toluene (T), group exposed to toluene and receiving OLE (T + OLE), group co-exposed to noise and toluene (NT), and group co-exposed to noise and toluene and receiving OLE (NT + OLE). The rats in this study were subjected to simultaneous exposure to toluene and noise for a duration of six weeks, within a custom-built plexiglass chamber. Toluene was administered at a concentration of 300 ppm, while the noise level was set to 85 dB(A). The exposure chamber was equipped with a generation system, an exposure system, and a monitoring system, ensuring precise and accurate exposure conditions. After the six-week period, heart and blood samples were collected from the rats for subsequent analysis. Plasma levels of cholesterol (CHOL), triglycerides (TG), lactate dehydrogenase (LDH), and creatine kinase (CK) were measured, and histopathological investigation was conducted using HE staining. Additionally, superoxide dismutase (SOD) and catalase (CAT) activities, as well as malondialdehyde (MDA) levels in heart tissue were measured. Our results showed that simultaneous exposure to noise and toluene altered CHOL, TG, LDH, and CK levels, and also caused an increase in lipid peroxidation levels and superoxide dismutase activity, along with a decrease in catalase activity in the heart. A significant alteration in the myocardium was also observed. However, treatment with OLE was found to modulate these oxidative and histological changes, ultimately correcting the deleterious effects induced by the combined exposure to noise and toluene. Therefore, our study suggests that OLE could be a potential preventive measure for individuals exposed to toluene and noise in industrial settings.