Protective effect and mechanism of styrax on ischemic stroke rats: metabonomic insights by UPLC-Q/TOF-MS analysis

Context: Styrax is used for prevention and treatment of cerebrovascular diseases. However, the underlying mechanism remains unclear. Objective: To elucidate styrax's anti-ischemic stroke protective effects and underlying mechanisms. Materials and methods: An ischemic-stroke rat model was established based on middle cerebral artery occlusion (MCAO). Sprague-Dawley rats were randomly assigned to the following groups (n 1/4 10) and administered intragastrically once a day for 7 consecutive days: sham, model, nimodipine (24 mg/kg), styrax-L (0.1 g/kg), styrax-M (0.2 g/kg) and styrax-H (0.4 g/kg). Neurological function, biochemical assessment, and ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-Q/TOFMS)-based serum metabonomics were used to elucidate styrax's cerebral protective effects and mechanisms. Pearson correlation and western blot analyses were performed to verify. Results: The addition of 0.4 g/kg styrax significantly reduced cerebral infarct volume and neurobehavioral abnormality score. Different doses of styrax also decrease MDA, TNF-a, IL-6, and IL-1b, and increase SOD and GSH-Px in ischemic-stroke rats (p< 0.05; MDA, p< 0.05 only at 0.4 g/kg dose). Biochemical indicators and metabolic-profile analyses (PCA, PLS-DA, and OPLS-DA) also supported styrax's protective effects. Endogenous metabolites (22) were identified in ischemic-stroke rats, and these perturbations were reversible via styrax intervention, which is predominantly involved in energy metabolism, glutathione and glutamine metabolism, and other metabolic processes. Additionally, styrax significantly upregulated phosphorylated AMP-activated protein kinase and glutaminase brain-tissue expression. Conclusion: Styrax treatment could ameliorate ischemic-stroke rats by intervening with energy metabolism and glutamine metabolism. This can help us understand the mechanism of styrax, inspiring more clinical application and promotion.