Neuroprotective effects of myrtenol against brain injury following isoproterenol-induced myocardial infarction in male rats.

Myocardial infarction (MI) induces brain injury. Myrtenol has antioxidant and anti-inflammatory effects. This study investigated the neuroprotective effect of myrtenol following myocardial infarction induced by isoproterenol (ISO) in male rats. This experimental study involved 36 male Wistar rats. They were divided into six groups. Rats received ISO (85 mg/kg) for two days. Subsequently, they were treated with vehicle or myrtenol (5, 25, or 50 mg/kg) once daily, one hour after the last ISO injection, for seven days. Behavioral tests (spontaneous alternation and passive avoidance) were conducted post-treatment. Hemodynamic parameters and serum troponin were assessed. Tissue samples (heart/brain tissue) underwent histopathological examination via H&E and Nissl staining methods. The activities of glutathione peroxidase (GPx), catalase, and superoxide dismutase (SOD), along with malondialdehyde (MDA) content and total antioxidant capacity (TAC) were measured in heart and brain tissue. Western blot analysis was used for the assessment of inflammatory (TNF and NF-κB), cell death (Bax, Bcl2, and Cleaved caspase-3), and nuclear factor erythroid-related factor-2 (Nrf2) markers in brain tissue. ISO significantly reduced latency time and spontaneous alternation compared to control (p < 0.001). Myrtenol improved these parameters at 25 mg/kg (p < 0.01) and 50 mg/kg (p < 0.001). Myrtenol also reduced MDA content, Bax, Cleaved caspase-3, TNF, and NF-κB protein expression and also increased Bcl2, and Nrf2 proteins, TAC level, SOD, GPx, and catalase enzyme activity in heart/brain tissues when compared to ISO group (p < 0.05). Myrtenol improved memory function and hemodynamic parameters. It decreases brain oxidative stress, inflammation and cell death markers, highlighting its potential as a therapeutic agent.