hydroxysafflor-yellow-a and Learning-Disabilities

Chronic stress plays a critical role in the etiology of sporadic Alzheimer's disease (AD). However, there are currently no effective drugs that can target chronic stress to prevent AD. In this study, we explored the neuroprotective effect of hydroxysafflor yellow A (HSYA) against chronic mild stress (CMS)-induced memory impairments in mice and the underlying mechanism. The Morris water maze test showed that HSYA significantly reduced CMS-induced learning and memory impairments in mice. HSYA increased the expression of brain-derived neurotrophic factor (BDNF) and activated downstream tropomyosin-related kinase B (TrkB) and phosphatidylinositol 3-kinase (PI3K)/protein kinase B(Akt)/mammalian target of rapamycin (mTOR) signaling. HSYA decreased the expression of regulator of calcineurin 1-1L (RCAN1-1L) that could promote the activity of glycogen synthase kinase-3β (GSK-3β). HSYA also attenuated tau phosphorylation by inhibiting the activity of GSK-3β and cyclin-dependent kinase-5 (Cdk5). Our data indicated that HSYA has protective effects against CMS-induced BDNF downregulation, tau phosphorylation and memory impairments. HSYA may be a promising therapeutic candidate for AD by targeting chronic stress.

Topics: Alzheimer Disease; Animals; Brain-Derived Neurotrophic Factor; Calcium-Binding Proteins; Chalcone; Disease Models, Animal; Gene Expression Regulation; Glycogen Synthase Kinase 3; Humans; Learning Disabilities; Membrane Glycoproteins; Memory Disorders; Mice; Muscle Proteins; Neuroprotective Agents; Phosphatidylinositol 3-Kinases; Phosphorylation; Protein-Tyrosine Kinases; Quinones; TOR Serine-Threonine Kinases

Hydroxysafflor yellow A (HSYA) has angiogenesis-regulating and neuro-protective effects, but its effects on vascular dementia (VaD) are unknown. In this study, 30 adult Sprague-Dawley rats were randomly allocated to five groups: normal, sham-operation, VaD alone (bilateral carotid artery occlusion), VaD plus saline (control), and VaD plus HSYA. One week after operation, the HSYA group received one daily tail-vein injection of 0.6 mg/100 g HSYA for two weeks. Five weeks after operation, the spatial memory of all five groups was evaluated by the water maze task, and synaptic plasticity in the hippocampus was assessed by the long-term potentiation (LTP) method. Vascular endothelial growth factor (VEGF) and N-methyl-Daspartic acid receptor 1 (NR1) expression in the hippocampus was detected via Western blot. We found that, compared with the group with VaD alone, the group with HSYA had a reduced escape latency in the water maze (P < 0.05), and the LTP at CA3-CA1 synapses in the hippocampus was enhanced (P < 0.05). Western blot in the late-phase VaD group showed slight up-regulation of VEGF and downregulation of NR1 in the hippocampus, while HSYA significantly up-regulated both VEGF and NR1. These results suggested that HSYA promotes angiogenesis and increases synaptic plasticity, thus improving spatial learning and memory in the rat model of VaD.

Topics: Animals; Carotid Artery Diseases; Chalcone; Dementia, Vascular; Disease Models, Animal; Electric Stimulation; Gene Expression Regulation; Hippocampus; Learning Disabilities; Long-Term Potentiation; Male; Maze Learning; Memory Disorders; Quinones; Random Allocation; Rats; Rats, Sprague-Dawley; Reaction Time; Receptors, N-Methyl-D-Aspartate; Time Factors; Vascular Endothelial Growth Factor A