Effect Of Jianrui Kangzhong Decoction On APP/PS1 Doubletransgenic Mice Cerebrovascular Endothelial Cells And Its Mechanism

BackgroundAlzheimer's Disease?AD?is a neurodegerative disease,however,its etiology and pathogenesis have not been elucidated yet.The typical pathological feature of AD includes aggregates of?-amyloid protein?A??to form senile plaques in the brain.Zlokovic proposed the neurovascular hypothesis of Alzheimer's disease,believed that inability of A?clearance and deposition of A?in the brain tissue are due to change in permeability of blood-brain barrier.The previous study has showed that Jianrui Kangzhong Decoction?JKD?can improve the ability of learning and memory and the permeability of blood-brain barrier in AD mice model,while its mechanism is still unclear.In this study,the effect of JKD on cerebrovascular endothelial cells and the underlying mechanism were studied by using APP/PS1 double transgenic mouse model,which is a commonly used AD studying model by many countries.ObjectiveUsing APP/PS1 double transgenic mice as AD mice model,the effect of Jianrui Kangzhong decoction on the cerebrovascular endothelial cells of APP/PS1 double transgenic mice was clarified,and the its intervention mechanism was discussed.Methods1.APP/PS1 double transgenic male mice were randomly divided into model group,donepezil group?0.001 g/kg?and JKD group?9.23 g/kg?.Wild-type mice with the same sex in the same nest were used as control group.After 45 days of continuous gavage,Morris Water Maze test was used to detect the learning and memory function of mice.2.The morphology of cerebrovascular endothelial cells and hippocampus were observed by transmission electron microscope and HE staining.3.The change of blood-brain barrier permeability was oberseverd by measuring Evans blue content in brain tissue of mice in each group.4.Immunohistochemistry and Western blot were used to detect the protein expression levels of A?1-42,APP,HIF-1?,VEGFA,VEGFR2 and ZO-1 in the brain of mice in each group.5.Real-time fluorescent quantitative PCR was used to detect the expression levels of A?_1-42,APP,HIF-1?,VEGFA,VEGFR2 and ZO-1 mRNA in the brain of mice in each group.6.SPSS 22.0 software was used for statistical analysis,P<0.05 is statistically significant.Results1.The water maze experiment showed that compared with the model group,the latency of JKD group and donepezil group were significantly shortened,the number of cross-platforms,target quadrant travel and time were significantly increased,and the difference was statistically significant?P<0.05?.2.HE staining showed that compared with the model group,the JKD group and donepezil group stained evenly and the cells were tightly arranged.3.Transmission electron microscope observation showed that compared with the model group,JKD group and donepezil group had regular cerebral blood vessel morphology,complete endothelial cell structure,clear organelle structure,and tight junctions between cells.4.The measurement results of Evans blue content in brain tissue showed that compared with the model group,the blood-brain barrier permeability of JKD group and donepezil group were significantly reduced,and the difference was statistically significant?P<0.05?.5.Immunohistochemistry and Western Blot results showed that compared with the model group,the protein expression levels of A?1-42,APP,HIF-1?,VEGFA,VEGFR2 in the brain of JKD group and donepezil group were significantly reduced,and the protein expression level of ZO-1 was significantly increased,the difference was statistically significant?P<0.05?.6.Real-time fluorescence quantitative PCR results showed that compared with the model group,the expression levels of A?1-42,APP,HIF-1?,VEGFA,VEGFR2mRNA in the brain of JKD group and donepezil group were significantly reduced,and the expression level of ZO-1mRNA was significantly increased,the difference was statistically significant?P<0.05?.ConclusionsJKD can improve the injury of cerebrovascular endothelial cells and hippocampal pathological damage of APP/PS1 double transgenic mice.JKD may increase the level of ZO-1 by inhibiting the VEGFA/VEGFR2 signal pathway induced by HIF-1?,thereby improving the blood-brain barrier permeability of APP/PS1 mice,reduce the level of A?in the brain,thereby improving the learning and memory function of mice.