Inhibition of notch signaling pathways contribute to neuroprotection effect by the combination of astragalus membranaceus and ligustrazine in rat model after thrombolysis of cerebral ischaemia

Objective: To investigate the neuroprotection effect of the combination of astragalus membranaceus and ligustrazine on thrombolysis after ischemic stroke and explore its mechanism basing on the Notch signaling pathway. Materials and methods: Focal cerebral ischemia models were induced by autologous thrombus of middle cerebral artery occlusion (MCAO). Male Sprague-Dawley (SD) rats were randomly divided into 3 experimental groups: MCAO group, Thrombolysis by rt-PA group, Thrombolysis+combination treatment group. Rt-PA (5mg/kg) was administrated 3h after MCAO onset and combination treatment of astragalus membranaceus and ligustrazine (0.1-0.2ml/100g) was administrated immediately after thrombolysis. Rats were sacrificed 3h and 24h after thrombolysis. The expression levels of Notch1, HES1 were detected by Western blotting (WB) and quantitative real-time PCR (RT-PCR). Results: Compared with those results of MCAO group and Thrombolysis by rt-PA group, Thrombolysis+ combination treatment group markedly decreased the expression of Notch1, HES1, in protein and mRNA, 3h after thrombolysis (P<;0.01, P<;0.01). And the trend of decrease was more pronounced at 24h (P<;0.01, P<;0.01). Conclusions: The findings demonstrate that the combination of astragalus membranaceus and ligustrazine might promote neuroprotection effect through down-regulation the activation of Notch1/HES1 signaling pathways.