Objective

2

To investigate the effect and mechanism of Guilu Erxiangao on Alzheimer's disease （AD） model rats induced by hydrocortisone and amyloid

β

-protein（A

β

） based on the theory of kidney-brain correlation.

Method

2

Intraperitoneal injection of hydrocortisone and intracerebroventricular injection of A

β

were performed to induce AD in rats， and different concentrations of Guilu Erxiangao were used for intervention. The indexes of hippocampus， kidney and adrenal gland were measured， and the spatial learning and memory ability of AD rats was observed by Morris water maze experiment. The levels of testosterone （T） and corticosterone （CORT） in serum samples were determined by enzyme-linked immunosorbent assay （ELISA）. Liquid chromatography-mass spectrometry （LC-MS） was used to collect and analyze the serum metabolic data of model rats. The active components and corresponding targets of Guilu Erxiangao were collected using Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform（TCMSP）， a Bioinformatics Analysis Tool for Molecular mechANism of Traditional Chinese Medicine （BATMAN-TCM） and Traditional Chinese Medicine Integrated Database（TCMID）. GeneCards and Online Mendelian Inheritance in Man （OMIM） were retrieved to obtain AD-related targets， and protein-protein interaction （PPI） network was constructed to perform gene ontology （GO）and Kyoto Encyclopedia of Genes and Genomes （KEGG） enrichment analysis. The expression level of interleukin-6 （IL-6） in the hippocampus of rats was detected by Western blot.

Result

2

Compared with the model group， the low-， medium- and high-dose groups of Guilu Erxiangao exhibited significantly increased hippocampus index， kidney index and adrenal gland index， reduced CORT levels in serum and down-regulated IL-6 levels in hippocampal tissues. According to the results of water maze experiment， as compared with the model group， the platform crossing times of rats was significantly increased in the low- and high-dose groups of Guilu Erxiangao， with evidently prolonged distance traveled in quadrant Ⅲ （%） and time in quadrant Ⅲ （%）. A total of 24 serum differential metabolites associated with AD were identified by LC-MS， and 50 high-frequency common compounds and 187 high-frequency common targets for AD treatment were screened by network pharmacology method. Results demonstrated phosphatidylinositol 3-kinases（PI3K）/protein kinase B（Akt） signaling pathway plays an important role in the complex AD pathological mechanism.

Conclusion

2

Guilu Erxiangao can significantly improve the cognitive dysfunction of AD model rats induced by hydrocortisone and A

β

， reduce serum CORT levels and IL-6 levels in hippocampal tissues， and regulate the metabolic level， which provides a reference for its clinical application.