Abstract: In this study,the protective effects and the mechanism of Safflor yellow B (SYB) on neuronal damage induced by okadaic acid (OA) in differentiated SH-SY5Y neuroblastoma cells were investigated.SH-SY5Y cells were differentiated with all-trans retinoic acid (ATRA) and treated with OA to induce high phosphorylation of Tau,which could build up a model of Alzheimer's Disease (AD) in vitro.Giemsa staining was used to observe the change in morphology of SH-SY5Y cells.Western blotting was applied to detect the levels of phosphorylation of Tau protein at 262 site.Flow cytometry was used to assess the production of reactive oxygen species (ROS) in the cells and mitochondria,and the change of mitochondrial membrane potential.The experimental results showed that treatment of ATRA could induce SH-SY5Y neuroblastoma cells to differentiate into mature neurons.OA can obvious cause neuronal synapse atrophy and phosphorylation of Tau on site of Ser-262.SYB can improve the neuronal damage induced by OA,depress the phosphorylation of Tau protein at Ser 262,decrease the intracellular and mitochondrial ROS production,and increase the mitochondrial membrane potential.

Key words: Safflor yellow B, SH-SY5Y neuroblastoma cells, Okada acid, Tau protein