Protective effects of Huang-Lian-Jie-Du-Tang against A25-35-induced memory deficits and oxidative stress in rats

Screening of the active Ingredients in Huanglian Jiedu decoction through amide bond-Immobilized magnetic nanoparticle-assisted cell membrane chromatography

Introduction: The Huanglian Jiedu decoction (HLJDD) is a Chinese herbal formula that exerts neuroprotective effects by alleviating oxidative stress injuries and may potentially be prescribed for treating Alzheimer's disease; however, its active ingredients have not yet been identified. Cell membrane chromatography is a high-throughput method for screening active ingredients, but traditional cell membrane chromatography requires multiple centrifugation steps, which affects its separation efficiency. Magnetic nanoparticles are unparalleled in solid-liquid separation and can overcome the shortcomings of traditional cell membrane chromatography. Methods: In this study, the neuroprotective effects of the components of HLJDD were screened through a novel magnetic nanoparticle-assisted cell membrane chromatography method. Magnetic nanoparticles and cell membranes were stably immobilized by amide bonds. Magnetic bead (MB)-immobilized cell membranes of HT-22 cells were incubated with the HLJDD extract to isolate specific binding components. The specific binding components were then identified by ultraperformance liquid chromatography (UPLC)-Orbitrap Fusion Tribrid MS after solid-phase extraction. The bioactivity of these components was analyzed in an HT-22 cellular model of glutamate-induced injury. Results and Discussion: The preparation method of the composite of cell membrane and MBs has the advantages of simple preparation and no introduction of toxic organic reagents. MBs not only provide support for cell membranes, but also greatly improve the separation efficiency compared with traditional cell membrane chromatography. Fifteen of these components were found to specifically bind to the cell membranes, and seven of them were confirmed to reduce varying degrees of glutamate-induced toxicity in HT-22 cells. In conclusion, our findings suggest that the amide bond-based immobilization of magnetic nanoparticles on cell membranes, along with solid-phase extraction and UPLC, is an effective method for isolating and discovering the bioactive components of traditional Chinese medicines.

Research progress in traditional Chinese medicine in the treatment of Alzheimer's disease and related dementias

Alzheimer's disease (AD) is the world's leading cause of dementia and has become a huge economic burden on nations and families. However, the exact etiology of AD is still unknown, and there are no efficient medicines or methods to prevent the deterioration of cognition. Traditional Chinese medicine (TCM) has made important contributions in the battle against AD based on the characteristics of multiple targets of TCM. This study reviewed the treatment strategies and new discoveries of traditional Chinese medicine in current research, which may be beneficial to new drug researchers.

Huang-Lian-Jie-Du decoction attenuates cognitive dysfunction of rats with type 2 diabetes by regulating autophagy and NLRP3 inflammasome activation

ETHNOPHARMACOLOGICAL RELEVANCE

Huang-Lian-Jie-Du decoction (HLJDD) is a traditional Chinese formula that is efficacious in treating diabetes mellitus, Alzheimer's disease, and diabetic encephalopathy; the underlying mechanisms of HLJDD in diabetes-associated cognitive dysfunction remain unclear.

AIM OF THE STUDY

This study investigated the neuroprotective effects of HLJDD on cognitive function, and the possible underlying mechanisms in type 2 diabetes mellitus (T2DM) in a rat model of cognitive impairment.

MATERIALS AND METHODS

Twelve active ingredients in HLJDD were detected using high-performance liquid chromatography analysis. An animal model of cognitive dysfunction in T2DM was induced via a high-sugar and high-fat diet combined with a low dose of streptozotocin. Sprague-Dawley rats were randomly divided into six groups: control, T2DM, metformin (0.34 g/kg/day), and HLJDD groups (3, 1.5, and 0.75 g/kg/day). All treatments were intragastrically administrated for nine continuous weeks after the development of T2DM. Body weight, food and water intake, fasting blood glucose, insulin sensitivity, and blood lipid levels were measured. Spatial learning and memory of the rats were assessed using the Morris water maze test. Hematoxylin and eosin and Nissl staining were performed to evaluate neuronal morphology and vitality. Glutathione, malondialdehyde, and superoxide dismutase levels were measured to determine the level of oxidative stress in the hippocampus. Transmission electron microscopy was performed to observe the synaptic morphology and structure of hippocampal neurons. IL-1β levels in the hippocampus and cerebrospinal fluid were determined. The protein expression of NLRP3, cleaved caspase-1, mature IL-1β, ATG7, P62, LC3, and brain-derived neurotrophic factor (BDNF) was determined using western blotting and immunofluorescence analysis.

RESULTS

HLJDD attenuated cognitive dysfunction in rats with T2DM as shown by the decreased escape latency, increased times crossing the platform and time spent in the target quadrant in the Morris water maze test (P < 0.05), improvement in hippocampal histopathological changes, and an elevated level of cell vitality. HLJDD treatment also reduced blood glucose and lipid levels, ameliorated oxidative stress, and downregulated IL-1β expression in the hippocampus and cerebrospinal fluid (P < 0.05). Moreover, HLJDD enhanced BDNF, ATG7, and LC3 protein expression and significantly inhibited the expression of P62, NLRP3, cleaved caspase-1, and mature IL-1β in the hippocampal CA1 region (P < 0.05). Immunofluorescence results further confirmed that the fluorescence intensity of NLRP3 and P62 in the hippocampus decreased after HLJDD intervention (P < 0.05).

CONCLUSIONS

HLJDD ameliorated cognitive dysfunction in T2DM rats. The neuroprotective effect is exerted via the modulation of glucose and lipid metabolism, upregulation of autophagy, and inhibition of NLRP3 inflammasome signaling pathway.

Jiedu-Yizhi Formula Improves Cognitive Impairment in an Aβ 25-35-Induced Rat Model of Alzheimer's Disease by Inhibiting Pyroptosis

Jiedu-Yizhi formula (JDYZF) is prescribed for the treatment of Alzheimer's disease (AD) and was created by Jixue Ren, a master of traditional Chinese medicine, based on the "marrow deficiency and toxin damage" theory. In our clinic, this formula has been used for the treatment of AD for many years and has achieved good results. However, the mechanism by which JDYZF improves cognitive impairment has not been determined. In this study, we confirmed that orally administered JDYZF reversed the cognitive deficits in an Aβ _25-35-induced rat model, increased the number of neurons in the hippocampal CA1 area, improved their structure, decreased the deposition of β-amyloid (Aβ), reduced the expression of proteins related to the NLRP3/Caspase-1/GSDMD and LPS/Caspase-11/GSDMD pyroptosis pathways, and reduced the levels of interleukin 1β (IL-1β) and IL-18, thereby inhibiting the inflammatory response. In addition, JDYZF exerted no hepatotoxicity in rats. In short, these results provide scientific support for the clinical use of JDYZF to improve the cognitive function of patients with AD.

The emerging possibility of the use of geniposide in the treatment of cerebral diseases: a review

With the advanced discoveries in the field of pathogenesis, a series of cerebral diseases, such as cerebral ischaemia, Alzheimer's disease, and depression, have been found to have multiple signalling targets in the microenvironment. Only a few existing agents have been shown to have curative effects due to this specific circumstance. In recent decades, active ingredients isolated from natural plants have been shown to be crucial for original drug development. Geniposide, mainly extracted from Gardenia jasminoides Ellis, is representative of these natural products. Geniposide demonstrates various biological activities in the treatment of cerebral, cardiovascular, hepatic, tumorous, and other diseases. The multiple protective effects of geniposide on the brain have especially drawn increasing attention. Thus, this article specifically reviews the characteristics of current models of cerebral ischaemia and illustrates the possible effects of geniposide and its pathogenetic mechanisms on these models. Geniposide has been shown to significantly reduce the area of cerebral infarction and alleviate neuronal damage and necrosis mainly by inhibiting inflammatory signals, including NLRP3, TNF-α, IL-6, and IL-1β. Neuronal protection was also involved in activating the PI3K/Akt and Wnt/catenin pathways. Geniposide was able to increase autophagy and inhibit apoptosis by regulating the function of mTOR in treating Alzheimer's disease. Geniposide has also been shown to act as a glucagon-like peptide-1 receptor (GLP-1R) agonist to reduce amyloid plaques and inhibit oxidative stress to alleviate memory impairment as well as synaptic loss. Moreover, geniposide has been shown to exert antidepressant effects primarily by regulating the hypothalamic-pituitary-adrenal (HPA) axis. Detailed explorations have shown that the biological activities of inhibiting inflammatory cytokine secretion, alleviating oxidative stress, and suppressing mitochondrial damage are also involved in the mechanism of action of geniposide. Therefore, geniposide is a promising agent awaiting further exploration for the treatment of cerebral diseases via various phenotypes or signalling pathways.

High-Fat Diet Alleviates Neuroinflammation and Metabolic Disorders of APP/PS1 Mice and the Intervention With Chinese Medicine

Alzheimer's disease (AD) is a progressive neurodegenerative disease caused by the complex interaction of multiple mechanisms. Recent studies examining the effect of high-fat diet (HFD) on the AD phenotype have demonstrated a significant influence on both inflammation and cognition. However, different studies on the effect of high-fat diet on AD pathology have reported conflicting conclusions. To explore the involvement of HFD in AD, we investigated phenotypic and metabolic changes in an AD mouse model in response to HFD. The results indicated there was no significant effect on Aβ levels or contextual memory due to HFD treatment. Of note, HFD did moderate neuroinflammation, despite spurring inflammation and increasing cholesterol levels in the periphery. In addition, diet affected gut microbiota symbiosis, altering the production of bacterial metabolites. HFD created a favorable microenvironment for bile acid alteration and arachidonic acid metabolism in APP/PS1 mice, which may be related to the observed improvement in LXR/PPAR expression. Our previous research demonstrated that Huanglian Jiedu decoction (HLJDD) significantly ameliorated impaired learning and memory. Furthermore, HLJDD may globally suppress inflammation and lipid accumulation to relieve cognitive impairment after HFD intervention. It was difficult to define the effect of HFD on AD progression because the results were influenced by confounding factors and biases. Although there was still obvious damage in AD mice treated with HFD, there was no deterioration and there was even a slight remission of neuroinflammation. Moreover, HLJDD represents a potential AD drug based on its anti-inflammatory and lipid-lowering effects.