Abstract: To explore the effect of luteolin-poloxamer nano-formulation on alleviating oxidative stress injury in vitro and in vivo.The nano-formulation was prepared by coating luteolin with F127 and characterized.The in vitro release behavior was determined by dialysis method.The H₂O₂-induced oxidative stress injury model of PC12 cells in vitro was established.For each group of cells,performing activity detection and cytoskeletal staining.The phosphorylation level of MAPK in each group of cells was detected by western-blot.The rat model of right cerebral ischemia-reperfusion injury was established by middle cerebral artery occlusion (MCAO) to evaluate the oxidative stress injury in vivo,and the cerebral infraction volume,brain water content and oxidative stress level in plasma (SOD,MDA,GSH-Px) were measured in each group.Finally,the pharmacokinetics of luteolin nano-formulation in rats was studied.The results showed that the luteolin nano-formulation is spherical with uniform particle size,high drug loading and encapsulation efficiency.Besides,the luteolin could be slowly released from the nano-formulation.The effect of alleviating oxidative stress in vivo and in vitro indicated that the luteolin nano-formulation could significantly improve cell viability and decrease p-JNK,p-P38 and p-ERK expression (P<0.01).Meanwhile,the cytoskeleton clearly showed a reticulated structure.The luteolin nano-formulation could significantly reduce the volume of cerebral infarction in rats (P<0.05),up-regulated SOD and GSH-Px levels (P<0.01),and down-regulated MDA levels (P<0.01).The effect of alleviating oxidative stress injury was significantly improved.It concluded that the luteolin nano-formulation could prolong its circulation time in vivo and increase its blood concentration,effectively reducing apoptpsis by inhibiting MAPK signal transduction pathway activation.

Key words: nano medicine, luteolin nano-formulation, oxidative stress, cerebral ischemia-reperfusion injury