Kai-Xin-San Improves Cognitive Impairment via Wnt/ß-Catenin and IRE1/XBP1s Signalings in APP/PS1 Mice.

Alzheimer's disease (AD) is the most common type of dementia with an insidious onset and slow progression. Kai-Xin-San (KXS) has been reported to be effective in improving cognitive impairment in AD. However, the mechanism is still confused. In this study, we employed APP/PS1 mice to explore the neuroprotective mechanism of KXS. Forty-eight male APP/PS1 mice were randomly divided into model group, KXS groups (0.7, 1.4, and 2.8 g/kg/d, p.o.) and the wild-type mice were assigned to the normal control group (n = 12 in each group). Y-maze and novel object recognition tests were carried out after continuous intragastric administration for 2 months. The abilities of learning, memory, and new object recognition in the APP/PS1 mice were enhanced significantly after KXS treatment. KXS can reduce the deposition of Aß40 and Aß42 in APP/PS1 mice brain. KXS decreased the levels of serum inflammatory cytokines, tumor necrosis factor-α, interleukin-1ß, and interleukin-6. KXS increased the activities of superoxide dismutase and glutathione peroxidase significantly, whereas it inhibited the contents of reactive oxygen species and malondialdehyde significantly. In addition, we also detected Wnt/ß-catenin signaling related proteins, such as Wnt7a, ß-catenin, low-density lipoprotein receptor-related protein 6 (LRP6), glycogen synthase kinase-3ß (GSK-3ß), nuclear factor kappa-B (NF-κB), postsynaptic density 95 (PSD95), microtubule associated protein-2 (MAP-2), and endoplasmic reticulum stress (IRE1 pathway) related proteins, such as inositol-requiring enzyme 1 (IRE1), phosphorylated IRE1(p-IRE1), spliced X-box-binding protein 1 (XBP1s), immunoglobulin binding protein (BIP), and protein disulfide isomerase (PDI) in the hippocampus. Results showed that KXS decreased the expression of GSK-3ß, NF-kB, p-IRE1/IRE1 ratio, XBP1s, and BIP; increased the expression of Wnt7a, ß-catenin, LRP6, PSD95, MAP2, and PDI. In conclusion, KXS improved cognitive impairment by activating Wnt/ß-catenin signaling, inhibiting the IRE1/XBP1s pathway in APP/PS1 mice.

Hydroxysafflor Yellow A Exerts Neuroprotective Effect by Reducing Aß Toxicity Through Inhibiting Endoplasmic Reticulum Stress in Oxygen-Glucose Deprivation/Reperfusion Cell Model.

Ischemia stroke is thought to be one of the vascular risks associated with neurodegenerative diseases, such as Alzheimer's disease (AD). Hydroxysafflor yellow A (HSYA) has been reported to protect against stroke and AD, while the underlying mechanism remains unclear. In this study, SH-SY5Y cell model treated with oxygen-glucose deprivation/reperfusion (OGD/R) was used to explore the potential mechanism of HSYA. Results from cell counting kit-8 (CCK-8) showed that 10 µM HSYA restored the cell viability after OGD 2 hours/R 24 hours. HSYA reduced the levels of malondialdehyde and reactive oxygen species, while improved the levels of superoxide dismutase and glutathione peroxidase. Furthermore, apoptosis was inhibited, and the expression of brain-derived neurotrophic factor was improved after HSYA treatment. In addition, the expression levels of amyloid-ß peptides (Aß) and BACE1 were decreased by HSYA, as well as the expression levels of binding immunoglobulin heavy chain protein, PKR-like endoplasmic reticulum (ER) kinase pathway, and activating transcription factor 6 pathway, whereas the expression level of protein disulfide isomerase was increased. Based on these results, HSYA might reduce Aß toxicity after OGD/R by interfering with apoptosis, oxidation, and neurotrophic factors, as well as relieving ER stress.