ABSTRACT
Objective:To investigate the neuroprotective effects of Danggui Shaoyaosan （DSS） on APP<sub>swe</sub>/PS1<sub>ΔE9 </sub>transgenic （APP/PS1） mice and its mechanism related to circular RNA （circRNA）. Method:Totally twenty 6-month-old APP/PS1 mice were divided into model group and DSS group， and 10 C57BL/6 wild-type mice were set as the normal control group. The normal group and model group received the same volume of normal saline， and DSS group received drug by gavage administration， all for 8 weeks. The differentially expressed circRNA of APP/PS1 mice before and after DSS intervention was analyzed by circRNA sequencing to construct circRNA-miRNA mRNA interaction network. The results of cricRNA sequencing were then verified by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR）. The protein expression levels of phosphoinositide 3-kinase （PI3K）， p-PI3K， protein kinase B1 （Akt1）， p-Akt1， B lymphocytoma-2 （Bcl-2）， and Bcl-2-Associated X protein （Bax） in the hippocampus were detected by immunoblotting （Western blot）. The protein expression of Caspase-3 in the hippocampus was detected by immunohistochemistry and the level of apoptosis in the hippocampus was detected by the TUNEL method. Result:Compared with the model group， there were 90 differentially expressed circRNA after intervention with DSS， of which 46 were up-regulated and 44 down-regulated. Compared with the normal group， the expression levels of circRNA1398 and circRNA1399 in the model group decreased， and the expression levels of miR-103-3p， miR-153-3p， miR-143-3p， and miR-143-5p increased. Compared with the model group， the expression levels of circRNA1398 and circRNA1399 in the DSS group were up-regulated， while the expression levels of miR-103-3p， miR-153-3p， miR-143-3p， and miR-143-5p were down-regulated. Compared with the normal group， the expression of p-PI3K， Akt1， p-Akt1， and Bcl-2 in the model group decreased （<italic>P</italic><0.05，<italic> P</italic><0.01）， and the expression of Bax and Caspase in the model group increased （<italic>P</italic><0.01）. Compared with the model group， the expression of p-PI3K， Akt1， p-Akt1， and Bcl-2 in the hippocampus of the DSS group increased （<italic>P</italic><0.01）， and the protein expression of Bax and Caspase decreased （<italic>P</italic><0.01）. Compared with the normal group， the apoptosis level in the hippocampus of the model group increased， with an apoptosis rate of （43.76±2.92）%. Compared with the model group， the apoptosis rate of DSS group was （24.64±3.39）%. Conclusion:DSS can activate PI3K/Akt pathway and inhibit apoptosis in hippocampal neurons of APP / PS1 mice， and play a neuroprotective role. The specific mechanism may be related to the regulation of circRNA1398 and circRNA1399 expression and the corresponding miRNA expression.