Combination of paeoniflorin and calycosin-7-glucoside alleviates ischaemic stroke injury via the PI3K/AKT signalling pathway

CONTEXT: Paeoniflorin (PF) and calycosin-7-glucoside (CG, Paeonia lactiflora Pall. extract) have demonstrated protective effects in ischaemic stroke. OBJECTIVE: To investigate the synergistic effects of PF + CG on ischaemia/reperfusion injury in vivo and in vitro. MATERIALS AND METHODS: Male Sprague-Dawley rats were subjected to the middle cerebral artery occlusion/reperfusion (MCAO/R). After MCAO/R for 24 h, rats were randomly subdivided into 5 groups: sham, model (MCAO/R), study treatment (PF + CG, 40 + 20 mg/kg), LY294002 (20 mg/kg), and study treatment + LY294002. Males were given via intragastric administration; the duration of the in vivo experiment was 8 days. Neurologic deficits, cerebral infarction, brain edoema, and protein levels were assessed in vivo. Hippocampal neurons (HT22) were refreshed with glucose-free DMEM and placed in an anaerobic chamber for 8 h. Subsequently, HT22 cells were reoxygenated in a 37 °C incubator with 5% CO(2) for 6 h. SOD, MDA, ROS, LDH and protein levels were measured in vitro. RESULTS: PF + CG significantly reduced neurobehavioral outcomes (21%), cerebral infarct volume (44%), brain edoema (1.6%) compared with the MCAO/R group. Moreover, PF + CG increased p-PI3K/PI3K (4.69%, 7.4%), p-AKT/AKT (6.25%, 60.6%) and Bcl-2/BAX (33%, 49%) expression in vivo and in vitro, and reduced GSK-3β (10.5%, 9.6%) expression. In vitro, PF + CG suppressed apoptosis in HT22 cells and decreased ROS and MDA levels (20%, 50%, respectively). CONCLUSIONS: PF + CG showed a synergistic protective effect against ischaemic brain injury, potentially being a future treatment for ischaemic stroke.