| Summary: | 碩士 === 國立陽明大學 === 藥理學研究所 === 105 === According to the Ministry of Health and Welfare, stroke is the third leading causes of death in Taiwan in 2015. Stroke is also one of the most common cardiovascular disease worldwide. More than 80% of stroke patients belong to the ischemic stroke type. It’s defined as the disturbance in the blood supply to the brain, and it causes the neuron damage and brain dysfunction quickly. Recombinant tissue-type plasminogen activator (rt-PA) is the only approved therapy for acute ischemic stroke. However, due to the short effective time window and hemorrhage side effect, the treatment for ischemic stroke needs further developments. YII is one of the key active components isolated from the protective herbal medicine based on our previous study. YII showed good neuroprotective effect in middle cerebral artery occlusion model (MCAO), but the neuroprotective mechanism of YII is still unknown. The aim of this study was to investigate the neuroprotective effect of YII and its underlying mechanisms of action by using an in vitro ischemic stroke model by inducing oxygen glucose deprivation (OGD) in Neuro-2a cells. The result showed that YII (20 μM) inhibited OGD-caused neural apoptosis by flow cytometry. The mechanisms of action in mediating YII’s neuroprotective effect was also elucidated by Western blotting. The protein expression levels of pS473Akt, pS9GSK3 and cleaved caspase 3 were significant decreased at 15 min, 60 min and 45-60 min after OGD, respectively. Bcl-2 was significant increased at 45 min after OGD. YII promoted the protein expression levels of pAkt, pSGSK3 and p35/Cdk5, which in turn may upregulate Bcl-2 and downregulate p25/Cdk5. Besides, YII might activate glucagon-like peptide 1 receptor (GLP-1R) and regulated downstream signaling pathway cAMP/PKA/CREB, which could be shown by cotreatment of YII with GLP-1R activator exendin-4 or GLP-1R inhibitor exendin-9. Finally, YII decreased the expression levels of caspase 3 in OGD model by immunofluorescence, but there was no difference in the change of an autophage marker LC3B. In conclusion, we propose that the neuroprotective effect of YII is most possibly involved GLP-1R signaling via modulation of PI3K/Akt/GSK3/p35Cdk5 and cAMP/PKA/CREB/Bcl-2 signaling pathways to protect neuronal cells against OGD-mediate cell injury.
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