Rhynchophylline ameliorates cerebral ischemia by improving the synaptic plasticity in a middle cerebral artery occlusion induced stroke model

Previous studies have documented that rhynchophylline exerts antioxidative and anti-inflammatory effects on ischemic neuronal damage in vitro or in vivo. There is a considerable lack of direct evidence for its role in neural function and neuroplasticity after ischemic stroke.This study aims to explore the role of rhynchophylline in middle cerebral artery occlusion (MCAO) induced ischemic stroke model and the potential mechanisms.Mice were randomly divided into the following three groups: Sham, MCAO + ddH2O, and MCAO + Rhy(40 mg/kg by oral gavage) groups. Cerebral ischemia was induced by MCAO. Cerebral blood flow was monitored to indicate the success of the ischemic model. The neurological severity score and a series of related behavior tests were performed(after MCAO 3d,7d,14d,21d,28d). Golgi staining and Sholl analysis were used to evaluate the complexity of dendrites and the density of dendritic spines. Immunohistochemistry was used to detect the expression of synapsin I and NeuN.Administration of rhynchophylline for 7 consecutive days after the onset of cerebral ischemia alleviated the sensory-motor functional defects and ameliorated hippocampus-dependent spatial memory injury as well as reduced the infarct volume induced by MCAO. However, golgi staining and sholl analysis showed that rhynchophylline improved dendritic complexity and spine density as well as the synaptic plasticity. Furthermore,the expression of synapsin I and Neun was significantly reduced after cerebral ischemia and rhynchophylline administration ameliorated the loss of synapsin I.Rhynchophylline is a promising treatment for ischemic stroke via improving synaptic plasticity and ameliorating the sensory-motor function.