baohuoside-i and Cognitive-Dysfunction

Restoring the compromised neurogenesis has been served as a potential strategy to rescue cognitive dysfunction of Alzheimer's disease (AD). In this study, we explored whether icarisid II (ICS II), a natural product possessing powerful neuroprotection, could recover the neurogenesis dysfunction of APP/PS1 mice, and investigated its underlying mechanisms. Our results showed that oral administration of ICS II could alleviate cognitive injuries of APP/PS1 mice, promote hippocampal neurogenesis, as well as stimulate Wnt/β-catenin signal pathway confirmed by upregulated Wnt-3a, phosphorylated glycogen synthase kinase-3β (p-GSK-3β), and β-catenin. ICS II also depressed mitochondrial fission evidenced by upregulated Mitofusin 1 (Mfn 1) and Mitofusin 2 (Mfn 2), and downregulated mitochondrial fission 1 protein (Fis 1), mitochondrial fission factor (Mff), and phosphorylated dynamin-related protein 1 (p-Drp 1). However, these effects of ICS II were blunted by XAV-939, an inhibitor of Wnt/β-catenin signaling pathway. In summary, our findings revealed that ICS II could improve neurogenesis and inhibit mitochondrial fission via activation of the Wnt/β-catenin signaling pathway, which contributed to cognitive function restoration of APP/PS1 mice. This study discovered a novel mechanism involving neurogenesis regulation underlying the therapeutic effects of ICS II against AD.

Topics: Alzheimer Disease; Amyloid beta-Protein Precursor; Animals; beta Catenin; Cognitive Dysfunction; Flavonoids; Glycogen Synthase Kinase 3 beta; Hippocampus; Mice; Mice, Transgenic; Neurogenesis; Oligopeptides; Wnt Signaling Pathway

Excitotoxicity is extensively recognized as a major pathological process of neuronal death and has been proved to play a key role in Alzheimer's disease (AD). ICS II, a flavonoid compound from Herba Epimedii Maxim, is attracting great interests due to its neuroprotective properties.. The present study was aimed to explore the effects of ICS II on cognitive dysfunction and apoptotic response induced by excitatory neurotoxin ibotenic acid (IBO) injection in rats.. Rats subjected to bilateral hippocampal injection of IBO were intragastrically administered with 4, 8 and 16 mg/kg ICS II or 0.6 mg/kg donepezil once a day for continuous 20 days. Learning and memory functions were tested by Morris water maze. The neuronal morphology in hippocampus was examined by HE staining and Nissl staining, respectively. Neuronal apoptosis was detected by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. The expression of apoptosis-related proteins and the activation of mitogen-activated protein kinase (MAPK) pathway were detected by Western blot.. It was uncovered that hippocampal injection of IBO caused learning and memory impairment, neuronal damage and loss, as well as pro-apoptotic response. ICS II administrated at doses of 8 and 16 mg/kg not only rescued behavioral performance, but also protected hippocampal neurons against neurotoxicity via suppressing the elevation of Bax/Bcl-2 ratio and the activation of caspase-3. Meanwhile, ICS II repressed the down-regulation of calbindin protein induced by IBO. Additionally, ICS II exerted an inhibitory effect on MAPK (p38, ERK1/2 and JNK) pathway phosphorylation.. These results suggest that ICS II attenuates IBO-induced cognitive deficits, possibly via the regulation of calbindin expression and the inhibition of apoptotic response. In addition, the MAPK signaling pathway is implicated in the potential mechanisms of ICS II against IBO-induced excitotoxicity, indicating that ICS II is a promising compound for treatment of excitotoxicity-related diseases, including AD.

Topics: Alzheimer Disease; Animals; Apoptosis; Calbindins; Caspase 3; Cognitive Dysfunction; Down-Regulation; Flavonoids; Hippocampus; Ibotenic Acid; Male; MAP Kinase Signaling System; Maze Learning; Memory Disorders; Neurons; Rats, Sprague-Dawley