RESUMO
Aim To investigate the effect of safflower yellow (SY) on learning and memory ability of APP/ PS1 mice at different disease stages, and to explore the mechanism of SY anti- Alzheimer's disease by using 3-,6- and 9-month-old APP/PS 1 transgenic mice as experimental animal models. Methods Behavioral experiments were conducted to observe the effects of SY on learning and memory of APP/PS1 mice of different months. ELISA was used to detect the effect of SY on the expression of inflammatory factors in cortex of mice of different months. Western blot was used to detect the microglia activation marker protein, and its mechanism of action was further analyzed. Results SY could enhance the learning and memory ability of mice aged 3, 6 and 9 months, reduce the content of IL-6 and increase the content of TGF-β1 in brain tissue, up-regulate the expression levels of arginase-1 (arg-1) and triggering receptor expressed on myeloid cells 2 (tREM2) in brain tissue of mice of different months, and down-regulate the expression levels of inducible nitric oxide synthase (iNOS), Toll-like receptors 4 (tlr4) and nuclear factor-kappa B (nf-KB). Conclusions Compared with 3- and 9-month-old mice, SY is the most effective in improving learning memory in 6-month-old APP/PS1 mice. SY inhibits TLR4/NF-KB pathway activation by inducing TREM2 expression in brain tissue of APP/PS 1 transgenic mice, promotes microglia phenotype shift to anti-inflammatory phenotype, reduces chronic neuroinflammatory response, and improves learning memory in APP/PS1 mice at all months of age.