The memory enhancement effect of Kai Xin San on cognitive deficit induced by simulated weightlessness in rats

IGF2BP2-Shox2 axis regulates hippocampal-neuronal senescence to alleviate microgravity-induced recognition disturbance

During space travel, microgravity leads to disturbances in cognitive function, while the underlying mechanism is still unclear. Simulated microgravity mice showed neuronal age-like changes in the hippocampus of our study. In the context of microgravity, we discovered m6A modification reshapes in the hippocampal region. When paired with RNA-seq and MeRIP-seq, Shox2 was found to be a powerful regulator in hippocampal neuron that respondes to microgravity. Decreased expression of senescence-associated secretory phenotype factors and improved genes related to synapses led to the restoration of memory function in the hippocampus upon increased expression of Shox2. Moreover, we discovered that IGF2BP2 was required for the m6A modification of the Shox2, and overexpressed IGF2BP2 in the hippocampus protected against both neuronal senescence and learning and memory decline caused by loss of gravity. Accordingly, our research identified the hippocampal IGF2BP2-Shox2 axis as a possible therapeutic approach to maintaining cognitive function during space travel.

Exploring the anti-ferroptosis mechanism of Kai-Xin-San against Alzheimer's disease through integrating network pharmacology, bioinformatics, and experimental validation strategy in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Kai Xin San (KXS), first proposed by Sun Simiao during the Tang Dynasty, has been utilized to treat dementia by tonifying qi and dispersing phlegm.

AIM OF THE STUDY

This study aimed to elucidate the mechanism by which KXS exerts its therapeutic effects on Alzheimer's disease (AD) by targeting ferroptosis, using a combination of network pharmacology, bioinformatics, and experimental validation strategies.

MATERIALS AND METHODS

The active target sites and the further potential mechanisms of KXS in protecting against AD were investigated through molecular docking, molecular dynamics simulation, and network pharmacology, and combined with the validation of animal experiments.

RESULTS

Computational and experimental findings provide the first indication that KXS significantly improves learning and memory defects and inhibits neuronal ferroptosis by repairing mitochondria damage and upregulating the protein expression of ferroptosis suppressor protein 1 (FSP1) in vivo APP/PS1 mice AD model. According to bioinformatics analysis, the mechanism by which KXS inhibits ferroptosis may involve SIRT1. KXS notably upregulated the mRNA and protein expression of SIRT1 in both vivo APP/PS1 mice and in vitro APP-overexpressed HT22 cells. Additionally, KXS inhibited ferroptosis induced by APP-overexpression in HT22 cells through activating the SIRT1-FSP1 signal pathway.

CONCLUSIONS

Collectively, our findings suggest that KXS may inhibit neuronal ferroptosis through activating the SIRT1/FSP1 signaling pathway. This study reveals the scientific basis and underlying modern theory of replenishing qi and eliminating phlegm, which involves the inhibition of ferroptosis. Moreover, it highlights the potential application of SIRT1 or FSP1 activators in the treatment of AD and other ferroptosis-related diseases.

Whole-transcriptome RNA sequencing reveals CeRNA regulatory network under long-term space composite stress in Rats

To systematically evaluate the effect of simulated long-term spaceflight composite stress (LSCS) in hippocampus and gain more insights into the transcriptomic landscape and molecular mechanism, we performed whole-transcriptome sequencing based on the control group (Ctrl) and the simulated long-term spaceflight composite stress group (LSCS) from six hippocampus of rats. Subsequently, differential expression analysis was performed on the Ctrl and LSCS groups, followed by enrichment analysis and functional interaction prediction analysis to investigate gene-regulatory circuits in LSCS. In addition, competitive endogenous RNA (ceRNA) network was constructed to gain insights into genetic interaction. The result showed that 276 differentially expressed messenger RNAs (DEmRNAs), 139 differentially expressed long non-coding RNAs (DElncRNAs), 103 differentially expressed circular RNAs (DEcircRNAs), and 52 differentially expressed microRNAs (DEmiRNAs) were found in LSCS samples compared with the controls, which were then subjected to enrichment analysis of Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways to find potential functions. PI3K-Akt signaling pathway and MAPK signaling pathway may play fundamental roles in the pathogenesis of LSCS. A ceRNA network was constructed with the predicted 340 DE pairs, which revealed the interaction roles of 220 DEmiRNA-DEmRNA pairs, 76 DEmiRNA-DElncRNA pairs, and 44 DEmiRNA-DEcircRNA pairs. Further, Thrombospondins2 was found to be a key target among those ceRNAs. Overall, we conducted for the first time a full transcriptomic analysis of the response of hippocampus to the LSCS that involved a potential ceRNA network, thus providing a basis to study the underlying mechanism of the LSCS.

Classic Famous Prescription Kai-Xin-San Ameliorates Alzheimer's Disease via the Wnt/β-Catenin Signaling Pathway

Kai-Xin-San (KXS) is a classic famous prescription composed of Polygalae Radix, Ginseng Radix et Rhizoma, Acori Tatarinowii Rhizoma, and Poria. Clinically, KXS is effective in treating amnesia and regulating cognitive dysfunction of Alzheimer's disease (AD), whereas its mechanism of action is still unclear. In this study, the AD model rats were established by combining intraperitoneal injection of D-galactose (150 mg/kg/day) and intracerebral injection of Aβ25-35 (10 μL) to investigate the meliorative effect of KXS on AD and explore its mechanism. After 1-month KXS treatment, Morris water maze test showed that different doses of KXS all improved the cognitive impairment of AD rats. The results of hematoxylin and eosin staining, Nissl staining, and Tunnel staining showed that the neuron injury in the hippocampal CA1 region of the AD rats was markedly improved after KXS treatment. Concurrently, KXS reversed the levels of biochemical indexes of AD rats. Furthermore, the protein expressions of Wnt1 and β-catenin in KXS groups were remarkably increased, while the expressions of Bax and caspase-3 were significantly decreased. Besides, KXS-medicated serum reduced the levels of tumor necrosis factor-α, interleukin-1β, and reactive oxygen species and regulated the protein expressions of β-catenin, glycogen synthase kinase-3β (GSK-3β), p-GSK-3β, Bax, and caspase-3 in Aβ25-35-induced pheochromocytoma cells. Most importantly, this effect was attenuated by the Wnt inhibitor IWR-1. Our results suggest that KXS improves cognitive and memory function of AD rats, and its neuroprotective mechanism may be mediated through the Wnt/β-catenin signaling pathway.

Constituents, pharmacological activities, pharmacokinetic studies, clinical applications, and safety profile on the classical prescription Kaixinsan

Kaixinsan (KXS) is a noteworthy classical prescription, which consists of four Chinese medicinal herbs, namely Polygalae Radix, Ginseng Radix et Rhizoma, Poria, and Acori Tatarinowii Rhizoma. KXS was initially documented in the Chinese ancient book Beiji Qianjin Yaofang written by Sun Simiao of the Tang Dynasty in 652 A.D. As a traditional Chinese medicine (TCM) prescription, it functions to nourish the heart and replenish Qi, calm the heart tranquilize the mind, and excrete dampness. Originally used to treat amnesia, it is now also effective in memory decline and applied to depression. Although there remains an abundance of literature investigating KXS from multiple aspects, few reviews summarize the features and research, which impedes better exploration and exploitation of KXS. This article intends to comprehensively analyze and summarize up-to-date information concerning the chemical constituents, pharmacology, pharmacokinetics, clinical applications, and safety of KXS based on the scientific literature, as well as to examine possible scientific gaps in current research and tackle issues in the next step. The chemical constituents of KXS primarily consist of saponins, xanthones, oligosaccharide esters, triterpenoids, volatile oils, and flavonoids. Of these, saponins are the predominant active ingredients, and increasing evidence has indicated that they exert therapeutic properties against mental disease. Pharmacokinetic research has illustrated that the crucial exposed substances in rat plasma after KXS administration are ginsenoside Re (GRe), ginsenoside Rb1 (GRb1), and polygalaxanthone III (POL). This article provides additional descriptions of the safety. In this review, current issues are highlighted to guide further comprehensive research of KXS and other classical prescriptions.

Research on the quality markers of antioxidant activity of Kai-Xin-San based on the spectrum-effect relationship

Background: Kai-Xin-San (KXS) is one of the classic famous traditional Chinese medicine prescriptions for amnesia, which has been applied for thousands of years. Modern pharmacological research has found that KXS has significant therapeutic efficacy on nervous system diseases, which is related to its antioxidant activity. However, the antioxidant material basis and quality markers (Q-makers) of KXS have not been studied. Objective: The objective of this study is to explore the Q-makers of antioxidant activity of KXS based on spectrum-effect relationship. Methods: Specifically, the metabolites in KXS extracts were identified by UPLC-Q-Exactive Orbitrap MS/MS. The fingerprint profile of KXS extracts were established by high-performance liquid chromatography (HPLC) and seven common peaks were identified. Meanwhile, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) test was used to evaluate the free radical scavenging ability of KXS. The spectrum-effect relationship between its HPLC fingerprint and DPPH free radical scavenging activity was preliminarily examined by the Pearson correlation analysis, grey relation analysis (GRA), and orthogonal partial least squares discrimination analysis (OPLS-DA). Further, the antioxidant effect of KXS and its Q-makers were validated through human neuroblastoma (SH-SY5Y) cells experiment. Results: The results showed that 103 metabolites were identified from KXS, and the similarity values between HPLC fingerprint of twelve batches of KXS were greater than 0.900. At the same time, the results of Pearson correlation analysis showed that the peaks 8, 1, 14, 17, 18, 24, 16, 21, 15, 13, 6, 5, and 3 from KXS were positively correlated with the scavenging activity values of DPPH. Combined with the results of GRA and OPLS-DA, peaks 1, 3, 5 (Sibiricose A6), 6, 13 (Ginsenoside Rg1), 15, and 24 in the fingerprints were screen out as the potential Q-makers of KXS for antioxidant effect. Besides, the results of CCK-8 assay showed that KXS and its Q-makers remarkably reduced the oxidative damage of SH-SY5Y cells caused by H2O2. However, the antioxidant activity of KXS was decreased significantly after Q-makers were knocked out. Conclusion: In conclusion, the metabolites in KXS were successfully identified by UPLC-Q-Exactive Orbitrap MS/MS, and the Q-makers of KXS for antioxidant effect was analyzed based on the spectrum-effect relationship. These results are beneficial to clarify the antioxidant material basis of KXS and provide the quality control standards for new KXS products development.

Time-course adaptive changes in hippocampal transcriptome and synaptic function induced by simulated microgravity associated with cognition

Introduction

The investigation of cognitive function in microgravity, both short-term and long-term, remains largely descriptive. And the underlying mechanisms of the changes over time remain unclear.

Methods

Behavioral tests, electrophysiological recording, and RNA sequencing were used to observe differences in behavior, synaptic plasticity, and gene expression.

Results

Initially, we measured the performance of spatial cognition exposed to long-term simulated microgravity (SM). Both working memory and advanced cognitive abilities were enhanced. Somewhat surprisingly, the synaptic plasticity of the hippocampal CA3-CA1 synapse was impaired. To gain insight into the mechanism of changing regularity over time, transcriptome sequencing in the hippocampus was performed. The analysis identified 20 differentially expressed genes (DEGs) in the hippocampus after short-term modeling, 19 of which were up-regulated. Gene Ontology (GO) analysis showed that these up-regulated genes were mainly enriched in synaptic-related processes, such as Stxbp5l and Epha6. This might be related to the enhancement of working memory performance under short-term SM exposure. Under exposure to long-term SM, 7 DEGs were identified in the hippocampus, all of which were up-regulated and related to oxidative stress and metabolism, such as Depp1 and Lrg1. Compensatory effects occurred with increased modeling time.

Discussion

To sum up, our current research indicates that the cognitive function under SM exposure is consistently maintained or potentially even being enhanced over both short and long durations. The underlying mechanisms are intricate and potentially linked to the differential expression of hippocampal-associated genes and alterations in synaptic function, with these effects being time-dependent. The present study will lay the experimental and theoretical foundation of the multi-level mechanism of cognitive function under space flight.

Fresh Gastrodia elata Blume alleviates simulated weightlessness-induced cognitive impairment by regulating inflammatory and apoptosis-related pathways

In aerospace medicine, the influence of microgravity on cognition has always been a risk factor threatening astronauts' health. The traditional medicinal plant and food material Gastrodia elata Blume has been used as a therapeutic drug for neurological diseases for a long time due to its unique neuroprotective effect. To study the effect of fresh Gastrodia elata Blume (FG) on cognitive impairment caused by microgravity, hindlimb unloading (HU) was used to stimulate weightlessness in mice. The fresh Gastrodia elata Blume (0.5 g/kg or 1.0 g/kg) was intragastrically administered daily to mice exposed to HU and behavioral tests were conducted after four weeks to detect the cognitive status of animals. The behavioral tests results showed that fresh Gastrodia elata Blume therapy significantly improved the performance of mice in the object location recognition test, Step-Down test, and Morris Water Maze test, including short-term and long-term spatial memory. According to the biochemical test results, fresh Gastrodia elata Blume administration not only reduced serum factor levels of oxidative stress but also maintained the balance of pro-inflammatory and anti-inflammatory factors in the hippocampus, reversing the abnormal increase of NLRP3 and NF-κB. The apoptosis-related proteins were downregulated which may be related to the activation of the PI3K/AKT/mTOR pathway by fresh Gastrodia elata Blume therapy, and the abnormal changes of synapse-related protein and glutamate neurotransmitter were corrected. These results identify the improvement effect of fresh Gastrodia elata Blume as a new application form of Gastrodia elata Blume on cognitive impairment caused by simulated weightlessness and advance our understanding of the mechanism of fresh Gastrodia elata Blume on the neuroprotective effect.

Protective effects of ginsenosides Rg1 and Rb1 against cognitive impairment induced by simulated microgravity in rats

Microgravity experienced during space flight is known to exert several negative effects on the learning ability and memory of astronauts. Few effective strategies are currently available to counteract these effects. Rg1 and Rb1, the major steroidal components of ginseng, have shown potent neuroprotective effects with a high safety profile. The present study aimed to investigate the effects of Rg1 and Rb1 on simulated microgravity-induced learning and memory dysfunction and its underlying mechanism in the hindlimb suspension (HLS) rat model. Administration of Rg1 (30 and 60 μmol/kg) and Rb1 (30 and 60 μmol/kg) for 2 weeks resulted in a significant amelioration of impaired spatial and associative learning and memory caused by 4-week HLS exposure, measured using the Morris water maze and Reward operating conditioning reflex (ROCR) tests, respectively. Furthermore, Rg1 and Rb1 administration alleviated reactive oxygen species production and enhanced antioxidant enzyme activities in the prefrontal cortex (PFC). Rg1 and Rb1 also assisted in the recovery of mitochondrial complex I (NADH dehydrogenase) activities, increased the expression of Mfn2 and decreased the fission marker dynamin-related protein (Drp)-1expression. Additionally, Rg1 and Rb1 treatment increased the SYN, and PSD95 protein expressions and decreased the ratio of Bax:Bcl-2 and reduced the expression of cleaved caspase-3 and cytochrome C. Besides these, the BDNF-TrkB/PI3K-Akt pathway was also activated by Rg1 and Rb1 treatment. Altogether, Rg1 and Rb1 treatment attenuated cognitive deficits induced by HLS, mitigated mitochondrial dysfunction, attenuated oxidative stress, inhibited apoptosis, increased synaptic plasticity, and restored BDNF-TrkB/PI3K-Akt signaling.

Kai-Xin-San Inhibits Tau Pathology and Neuronal Apoptosis in Aged SAMP8 Mice

Alzheimer’s disease (AD) is an age-related neurological disorder. Currently, there is no effective cure for AD due to its complexity in pathogenesis. In light of the complex pathogenesis of AD, the traditional Chinese medicine (TCM) formula Kai-Xin-San (KXS), which was used for amnesia treatment, has been proved to improve cognitive function in AD animal models. However, the active ingredients and the mechanism of KXS have not yet been clearly elucidated. In this study, network pharmacology analysis predicts that KXS yields 168 candidate compounds acting on 863 potential targets, 30 of which are associated with AD. Enrichment analysis revealed that the therapeutic mechanisms of KXS for AD are associated with the inhibition of Tau protein hyperphosphorylation, inflammation, and apoptosis. Therefore, we chose 7-month-old senescence-accelerated mouse prone 8 (SAMP8) mice as AD mouse model, which harbors the behavioral and pathological hallmarks of AD. Subsequently, the potential underlying action mechanisms of KXS on AD predicted by the network pharmacology analyses were experimentally validated in SAMP8 mice after intragastric administration of KXS for 3 months. We observed that KXS upregulated AKT phosphorylation, suppressed GSK3β and CDK5 activation, and inhibited the TLR4/MyD88/NF-κB signaling pathway to attenuate Tau hyperphosphorylation and neuroinflammation, thus suppressing neuronal apoptosis and improving the cognitive impairment of aged SAMP8 mice. Taken together, our findings reveal a multi-component and multi-target therapeutic mechanism of KXS for attenuating the progression of AD, contributing to the future development of TCM modernization, including KXS, and broader clinical application.

Kai-Xin-San Attenuates Doxorubicin-Induced Cognitive Impairment by Reducing Inflammation, Oxidative Stress, and Neural Degeneration in 4T1 Breast Cancer Mice

Objective

This study explored the potential therapeutic effect and possible mechanism of Kai-Xin-San (KXS) on doxorubicin-induced cognitive impairment in 4T1 breast cancer mice.

Methods

A model of chemotherapy-induced cognitive impairment (CICI) was established with the injection of doxorubicin (DOX, 5 mg/kg) at a 7-day interval in a 4T1 breast cancer mouse. KXS was given (1 g/kg) daily by gavage over three weeks starting at the first week while giving DOX. The Morris water maze task was performed to measure the CICI-like behaviors. Oxidative stress markers in the hippocampus, inflammatory cytokines in the serum and hippocampus, Nissl staining, immunofluorescence staining, and analysis for Glial fibrillary acidic protein and ionized calcium-binding adapter molecule 1 of the hippocampus were examined to explore the effect and mechanism of KXS on DOX-induced CICI. Meanwhile, tumor growth and survival time were tested in this study.

Results

CICI-like behaviors induced by DOX occurred earlier and were severer than the cognitive impairment induced by the tumor, and the effect of KXS on improving the cognitive impairment was obvious. KXS protected against DOX-induced neuroinflammation by decreasing levels of proinflammatory cytokines interleukin-6, interleukin-12p70, and tumor necrosis factor-alpha in both serum and brain and interleukin-1β in the brain, increasing the anti-inflammatory cytokines interleukin-4 in the serum and interleukin-10 in the hippocampus, and inhibiting the astrocytic hyperplasia and microglial polarization in the hippocampus. KXS reduced neural degeneration and protected against DOX-induced oxidative stress according to decreased malondialdehyde level, increased glutathione level, and enhanced activities of superoxide dismutase, catalase, and glutathione peroxidase. Moreover, KXS recovered the lost body weights after DOX administration and prolonged the survival times of mice.

Conclusions

KXS may attenuate DOX-induced cognitive impairment by regulating inflammatory responses and reducing oxidative stress and neural degeneration. These findings also presented the role of KXS in improving the quality of life and prolonging survival time in breast cancer mice that received chemotherapy.

Mitochondrial Protection and Against Glutamate Neurotoxicity via Shh/Ptch1 Signaling Pathway to Ameliorate Cognitive Dysfunction by Kaixin San in Multi-Infarct Dementia Rats

Multi-infarct dementia (MID), a prominent subtype of vascular dementia (VD), is responsible for at least 15 to 20 percent of dementia in the elderly. Mitochondrial dysfunctions and glutamate neurotoxicity due to chronic hypoperfusion and oxidative stress were regarded as the major risk factors in the pathogenesis. Kaixin San (KXS), a classic prescription of Beiji Qianjin Yaofang, was applied to treatment for "amnesia" and has been demonstrated to alleviate the cognitive deficit in a variety of dementias, including MID. However, little is known whether mitochondria and glutamate are associated with the protection of KXS in MID treatment. The aim of this study was to investigate the role of KXS in improving the cognitive function of MID rats through strengthening mitochondrial functions and antagonizing glutamate neurotoxicity via the Shh/Ptch1 signaling pathway. Our data showed that KXS significantly ameliorated memory impairment and hippocampal neuron damage in MID rats. Moreover, KXS improved hippocampal mitochondrial functions by reducing the degree of mitochondrial swelling, increasing the mitochondrial membrane potential (MMP), and elevating the energy charge (EC) and ATP content in MID rats. As expected, the concentration of glutamate and the expression of p-NMDAR1 were significantly reduced by KXS in the brain tissue of MID rats. Furthermore, our results showed that KXS noticeably activated the Shh/Ptch1 signaling pathway which was demonstrated by remarkable elevations of Ptch1, Smo, and Gli1 protein levels in the brain tissue of MID rats. Intriguingly, the inhibition of the Shh signaling pathway with cyclopamine significantly inhibited the protective effects of KXS on glutamate-induced neurotoxicity in PC12 cells. To sum up, these findings suggested that KXS protected MID rats from memory loss by rescuing mitochondrial functions as well as against glutamate neurotoxicity through activating Shh/Ptch1 signaling pathway.

Recent Advances in Panax ginseng C.A. Meyer as a Herb for Anti-Fatigue: An Effects and Mechanisms Review

As an ancient Chinese herbal medicine, Panax ginseng C.A. Meyer (P. ginseng) has been used both as food and medicine for nutrient supplements and treatment of human diseases in China for years. Fatigue, as a complex and multi-cause symptom, harms life from all sides. Millions worldwide suffer from fatigue, mainly caused by physical labor, mental stress, and chronic diseases. Multiple medicines, especially P. ginseng, were used for many patients or sub-healthy people who suffer from fatigue as a treatment or healthcare product. This review covers the extract and major components of P. ginseng with the function of anti-fatigue and summarizes the anti-fatigue effect of P. ginseng for different types of fatigue in animal models and clinical studies. In addition, the anti-fatigue mechanism of P. ginseng associated with enhancing energy metabolism, antioxidant and anti-inflammatory activity is discussed.

Simulated weightlessness induces cognitive changes in rats illustrated by performance in operant conditioning tasks

The weightless environment encountered in space flight can cause cognitive changes, affecting mission execution and endanger mission safety. Ground simulations provide the means to evaluate these effects and the resulting risks. In this study, rats were used as model animals and subjected to simulated weightlessness by suspending them from their tails. Tail-suspension and operant task learning experiments were conducted to study the effects of simulated weightlessness on the complex operant conditioning abilities of the subject's acquisition, maintenance, and signal discrimination skills. The results showed that simulated weightlessness did not affect the animals' acquisition abilities but did affect their ability to maintain learned reflexes and recognize signals. This study may have general potential to research the effects of weightlessness on cognition in the space environment.

Protective effect of ginsenoside Rb1 against chronic restraint stress (CRS)-induced memory impairments in rats

Ginsenoside Rb1 (Rb1) is one of the most active components found in ginseng and provides important benefits to the central nervous system, especially for the improvement of learning and memory. Previous studies demonstrated that Rb1 protected against scopolamine-induced amnesia and exhibited memory-enhancing effects in the SAMP8 mouse model. However, the effects of Rb1 against chronic restraint stress (CRS)-induced cognitive impairments, especially the role of Rg1 on the performance of reward directed instrumental conditioning have not been investigated. In this study, rats were subjected to CRS (6 h/day) for 28 days. Thereafter, behavioural tests including reward-directed instrumental conditioning task (RICT) and the Morris water maze (MWM) task were conducted. Administered of Rb1 (6.75 and 13.5 mg/kg, i.p.) remarkably ameliorated the memory impairments caused by CRS as evident from the results of RICT and MWM task, and this effect was accompanied by noticeable alterations in the levels of oxidative markers (superoxide dismutase, catalase, and lipid peroxidation) in the hippocampus. Additionally, Rb1 reduced the ratio of Bax:Bcl-2 and the expression of cleaved caspase-3 and cleaved caspase-9, increased the levels of synaptophysin (SYP) and postsynaptic density 95 (PSD95) and activated the BDNF/TrkB pathway in the hippocampus. In summary, the present study demonstrated that Rb1 rescues cognitive deficits induced by CRS is partially mediated by antagonizing oxidative stress and apoptosis, improving synaptic plasticity and restoring the BDNF/TrkB signalling pathway. This newly discovered effect of Rb1 sheds light on its applications in the development of therapeutic interventions to alleviate the deleterious effects of chronic stress.

The Cognitive-Enhancing Effects of Dendrobium nobile Lindl Extract in Sleep Deprivation-Induced Amnesic Mice

Chronic sleep deprivation (SD) causes neurological and neurodegenerative dysfunction including learning and memory deficit. The orchid Dendrobium nobile Lindl (DNL), is widely used as a Yin tonic and medicinal food throughout Asia, and has many reported pharmacological effects. This study focused on the cognitive-enhancing effects of DNL in sleep deprivation-induced amnesia in mice and its biochemical mechanisms. Our results showed that the mice displayed significant cognitive deficits after 2-week SD while treatment with the extract of DNL prevented these impairments. In the novel object recognition and object location recognition tasks, a significant increase in the discrimination index was observed in DNL-treated (200 and 400 mg/kg) mice. In the MWM test, DNL (200 and 400 mg/kg) treatment shorten the prolongation of latency and increased the crossing numbers compared with SD mice. The biochemical analysis of brain tissue showed a decrease in NE, dismutase (T-SOD) and catalase (CAT) activity and an increase in 5-HT and malondialdehyde (MDA) concentration after the treatment with DNL in mice. Our findings indicated that DNL exerted a positive effect in preventing and improving cognitive impairment induced by SD, which may be mediated via the regulation of neurotransmitters and alleviation of oxidative stress.

Dammarane Sapogenins Improving Simulated Weightlessness-Induced Depressive-Like Behaviors and Cognitive Dysfunction in Rats

Background: Our studies demonstrated that the space environment has an impact on the brain function of astronauts. Numerous ground-based microgravity and social isolation showed that the space environment can induce brain function damages in humans and animals. Dammarane sapogenins (DS), an active fraction from oriental ginseng, possesses neuropsychic protective effects and has been shown to improve depression and memory. This study aimed to explore the effects and mechanisms of DS in attenuating depressive-like behaviors and cognitive deficiency induced by simulated weightlessness and isolation [hindlimb suspension and isolation (HLSI)] in rats. Methods: Male rats were orally administered with two different doses of DS (37.5, 75 mg/kg) for 14 days, and huperzine-A (1 mg/kg) served as positive control. Rats were subjected to HLSI for 14 days except the control group during drug administration. The depressive-like behaviors were then evaluated by the open-field test, the novel object recognition test, and the forced swimming test. The spatial memory and working memory were evaluated by the Morris water maze (MWM) test, and the related mechanism was further explored by analyzing the activity of choline acetyltransferase (ChAT), acetylcholinesterase (AChE), and superoxide dismutase (SOD) in the hippocampus of rats. Results: The results showed that DS treatment significantly reversed the HLSI-induced depressive-like behaviors in the open-field test, the novel object recognition test, and the forced swimming test and improved the HLSI-induced cognitive impairment in the MWM test. Furthermore, after DS treatment, the ChAT and SOD activities of HLSI rats were increased while AChE activity was significantly suppressed. Conclusions: These findings clearly demonstrated that DS might exert a significant neuropsychic protective effect induced by spaceflight environment, driven in part by the modulation of cholinergic system and anti-oxidation in the hippocampus.

Comparison of the Protective Effects of Ginsenosides Rb1 and Rg1 on Improving Cognitive Deficits in SAMP8 Mice Based on Anti-Neuroinflammation Mechanism

This present study was designed to investigate the different effects of ginsenosides Rb1 and Rg1 on improving cognitive deficits in 4-month-old SAMP8 mice. Mice were divided into six groups, including the SAMP8 group, the SAMP8 + Donepezil (1.6 mg/kg) group, the SAMP8 + Rb1 (30 and 60 µmol/kg), and SAMP8 + Rg1 (30 and 60 µmol/kg) groups. SAMR1 mice of the same age were used as the control group. Ginsenosides and donepezil were administrated orally to animals for 8 weeks, then the learning and memory ability of mice were measured by using Morris water maze (MWM) test, object recognition test and passive avoidance experiments. The possible mechanisms were studied including the anti-glial inflammation of Rb1 and Rg1 using HE staining, immunohistochemistry and western blot experiments. Results revealed that Rb1 and Rg1 treatment significantly improved the discrimination index of SAMP8 mice in the object recognition test. Rb1 (60 µmol/kg) and Rg1 (30, 60 µmol/kg) could significantly shorten the escape latency in the acquisition test of the MWM test in SAMP8 mice. Furthermore, Rb1 and Rg1 treatments effectively reduced the number of errors in the passive avoidance task in SAMP8 mice. Western blot experiments revealed that Rb1 showed higher effect than Rg1 in decreasing protein expression levels of ASC, caspase-1 and Aβ in the hippocampus of SAMP8 mice, while Rg1 was more effective than Rb1 in decreasing the protein levels of iNOS. In addition, although Rb1 and Rg1 treatments showed significant protective effects in repairing neuronal cells loss and inhibiting the activation of astrocyte and microglia in hippocampus of SAMP8 mice, Rb1 was more effective than Rg1. These results suggest that Rb1 and Rg1 could improve the cognitive impairment in SAMP8 mice, and they have different mechanisms for the treatment of Alzheimer's disease.

Challenges to the central nervous system during human spaceflight missions to Mars

Space travel presents a number of environmental challenges to the central nervous system, including changes in gravitational acceleration that alter the terrestrial synergies between perception and action, galactic cosmic radiation that can damage sensitive neurons and structures, and multiple factors (isolation, confinement, altered atmosphere, and mission parameters, including distance from Earth) that can affect cognition and behavior. Travelers to Mars will be exposed to these environmental challenges for up to 3 years, and space-faring nations continue to direct vigorous research investments to help elucidate and mitigate the consequences of these long-duration exposures. This article reviews the findings of more than 50 years of space-related neuroscience research on humans and animals exposed to spaceflight or analogs of spaceflight environments, and projects the implications and the forward work necessary to ensure successful Mars missions. It also reviews fundamental neurophysiology responses that will help us understand and maintain human health and performance on Earth.

Beneficial Effects of Sagacious Confucius' Pillow Elixir on Cognitive Function in Senescence-Accelerated P8 Mice (SAMP8) via the NLRP3/Caspase-1 Pathway

Sagacious Confucius' Pillow Elixir (SCPE) is a traditional Chinese medicine that is mainly used for cognitive impairment in aging; however, the underlying mechanisms remain unclear. Aging is one of the most important pathogenic factors leading to inflammation and pyroptosis in the hippocampus, which may be a potential mechanism in elderly patients with cognitive impairment. Here, we examined whether SCPE could improve cognitive impairment in SAMP8 mice by reducing hippocampal inflammation and pyroptosis. Seven-month-old senescence-accelerated P8 mice (SAMP8) received SCPE (2.3 g/kg/day; 4.6 g/kg/day; 9.2 g/kg/day) for 28 days. Cognitive function and morphometric examinations were performed followed by water maze testing, hematoxylin-eosin staining, Congo red staining, toluidine blue staining, and TUNEL analysis of hippocampal CA1 and CA3 regions. Escape latency increased and times across platforms decreased in SAMP8 mice; however, both of them were normalized by SCPE after 28 days. Aging caused significant pyroptosis in hippocampal CA1 and CA3 regions, as evidenced by neuronal degeneration and necrosis, amyloid deposition, and decreased Nissl body amounts after cognitive impairment, which were greatly improved by SCPE. SCPE reduced serum IL-1β, IL-6, IL-18, and TNF-α levels and reduced hippocampal NLRP3, ASC, caspase-1, GSDM-D, IL-1β, IL-6, IL-18, and Aβ expression. Thus, SCPE exerts an antipyroptotic effect in aging, mainly by suppressing the NLRP3/caspase-1 signaling pathway.

Mechanisms of Panax ginseng action as an antidepressant

OBJECTIVES

Panax ginseng, a well-known traditional Chinese medicine with multiple pharmacological activities, plays a crucial role in modulating mood disorders. Several recent studies have identified an underlying role of Panax ginseng in the prevention and treatment of depression. However, the cellular and molecular mechanisms remain unclear.

MATERIALS AND METHODS

In this review, we summarized the recent progress of antidepressant effects and underlying mechanisms of Panax ginseng and its representative herbal formulae.

RESULTS

The molecular and cellular mechanisms of Panax ginseng and its herbal formulae include modulating monoamine neurotransmitter system, upregulating the expression of neurotrophic factors, regulating the function of HPA axis, and anti-inflammatory action.

CONCLUSIONS

Therefore, this review may provide theoretical bases and clinical applications for the treatment of depression by Panax ginseng and its representative herbal formulae.

Kai Xin San ameliorates scopolamine-induced cognitive dysfunction

Kai Xin San (KXS, containing ginseng, hoelen, polygala, and acorus), a traditional Chinese herbal compound, has been found to regulate cognitive dysfunction; however, its mechanism of action is still unclear. In this study, 72 specific-pathogen-free male Kunming mice aged 8 weeks were randomly divided into a vehicle control group, scopolamine group, low-dose KXS group, moderate-dose KXS group, high-dose KXS group, and positive control group. Except for the vehicle control group and scopolamine groups (which received physiological saline), the doses of KXS (0.7, 1.4 and 2.8 g/kg per day) and donepezil (3 mg/kg per day) were gastrointestinally administered once daily for 2 weeks. On day 8 after intragastric treatment, the behavioral tests were carried out. Scopolamine group and intervention groups received scopolamine 3 mg/kg per day through intraperitoneal injection. The effects of KXS on spatial learning and memory, pathological changes of brain tissue, expression of apoptosis factors, oxidative stress injury factors, synapse-associated protein, and cholinergic neurotransmitter were measured. The results confirmed the following. (1) KXS shortened the escape latency and increased residence time in the target quadrant and the number of platform crossings in the Morris water maze. (2) KXS increased the percentage of alternations between the labyrinth arms in the mice of KXS groups in the Y-maze. (3) Nissl and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining revealed that KXS promoted the production of Nissl bodies and inhibited the formation of apoptotic bodies. (4) Western blot assay showed that KXS up-regulated the expression of anti-apoptotic protein Bcl-2 and inhibited the expression of pro-apoptotic protein Bax. KXS up-regulated the expression of postsynaptic density 95, synaptophysin, and brain-derived neurotrophic factor in the cerebral cortex and hippocampus. (5) KXS increased the level and activity of choline acetyltransferase, acetylcholine, superoxide dismutase, and glutathione peroxidase, and reduced the level and activity of acetyl cholinesterase, reactive oxygen species, and malondialdehyde through acting on the cholinergic system and reducing oxidative stress damage. These results indicate that KXS plays a neuroprotective role and improves cognitive function through reducing apoptosis and oxidative stress, and regulating synapse-associated protein and cholinergic neurotransmitters.

A Computational Systems Pharmacology Approach to Investigate Molecular Mechanisms of Herbal Formula Tian-Ma-Gou-Teng-Yin for Treatment of Alzheimer's Disease

Traditional Chinese medicine (TCM) is typically prescribed as formula to treat certain symptoms. A TCM formula contains hundreds of chemical components, which makes it complicated to elucidate the molecular mechanisms of TCM. Here, we proposed a computational systems pharmacology approach consisting of network link prediction, statistical analysis, and bioinformatics tools to investigate the molecular mechanisms of TCM formulae. Taking formula Tian-Ma-Gou-Teng-Yin as an example, which shows pharmacological effects on Alzheimer’s disease (AD) and its mechanism is unclear, we first identified 494 formula components together with corresponding 178 known targets, and then predicted 364 potential targets for these components with our balanced substructure-drug–target network-based inference method. With Fisher’s exact test and statistical analysis we identified 12 compounds to be most significantly related to AD. The target genes of these compounds were further enriched onto pathways involved in AD, such as neuroactive ligand–receptor interaction, serotonergic synapse, inflammatory mediator regulation of transient receptor potential channel and calcium signaling pathway. By regulating key target genes, such as ACHE, HTR2A, NOS2, and TRPA1, the formula could have neuroprotective and anti-neuroinflammatory effects against the progression of AD. Our approach provided a holistic perspective to study the relevance between TCM formulae and diseases, and implied possible pharmacological effects of TCM components.

iTRAQ-based proteomics analysis of hippocampus in spatial memory deficiency rats induced by simulated microgravity

It has been demonstrated that simulated microgravity (SM) may lead to cognitive dysfunction. However, the underlying mechanism remains unclear. In present study, tail-suspension (30°) rat was employed to explore the effects of 28 days of SM on hippocampus-dependent learning and memory capability and the underlying mechanisms. We found that 28-day tail-suspension rats displayed decline of learning and memory ability in Morris water maze (MWM) test. Using iTRAQ-based proteomics analysis, a total of 4774 proteins were quantified in hippocampus. Of these identified proteins, 147 proteins were differentially expressed between tail-suspension and control group. Further analysis showed these differentially expressed proteins (DEPs) involved in different molecular function categories, and participated in many biological processes. Based on the results of PANTHER pathway analysis and further western blot verification, we observed the expression of glutamate receptor 1 (GluR1) and glutamate receptor 4 (GluR4) which involved in metabotropic glutamate receptor group III pathway and ionotropic glutamate receptor pathway were significantly induced by SM. Moreover, an increased concentration of glutamic acid (Glu) was also found in hippocampus while the concentrations of 5-hydroxytryptamine (5-HT), dopamine (DA), γ-amino acid butyric acid (GABA) and epinephrine (E) were decreased. Our finding confirms that 28-day SM exposure can cause degrading of the spatial learning and memory capability and the possible mechanisms might be related with glutamate excitotoxicity and imbalances in specific neurotransmitters.

BIOLOGICAL SIGNIFICANCE

The goal of sending astronauts farther into space and extending the duration of spaceflight missions from months to years will challenge the current capabilities of bioastronautics. The investigation of the physiological and pathological changes induced by spaceflight will be critical in developing countermeasures to ensure astronauts to complete spaceflight mission accurately and effectively and return to earth safely. It has been demonstrated that spaceflight may lead to impairments in cognitive function which is crucial for mission success. Here we show that long-term simulated microgravity, the most potent environment risk factor during spaceflight, impairs the spatial learning and memory of rats and the underlying mechanism may be involved in glutamate excitotoxicity and imbalances in specific neurotransmitters release in hippocampus, which may provide new insight for the countermeasures of cognitive impairment during spaceflight.

Kai-Xin-San, a traditional Chinese medicine formulation, exerts antidepressive and neuroprotective effects by promoting pCREB upstream pathways

Kai-Xin-San (KXS) is a traditional Chinese medicine that has been widely used for the treatment of emotion-related disease. However, the underlying mechanism remains largely unknown. The present study aimed to examine whether phospho-cAMP response element-binding protein (pCREB) and upstream components, such as extracellular signal-regulated kinase (ERK), phospho-ERK (pERK), phosphatidylinositol-3-kinase (PI3K), protein kinase B (Akt), glycogen synthase kinase 3β (GSK3β) and pGSK3β are associated with the antidepressive effect of KXS. In total, 24 male Wistar rats were randomly divided into three groups, including control (n=8, no treatment), induced with chronic unpredictable mild stress (CMS) (n=8), and CMS rats treated with KXS at dosage of 370 mg/kg/day orally. Primary hippocampal neuronal cultures were prepared from Wistar rats for cell survival and proliferation assays. In KXS rats, increased protein expression levels of pCREB, BDNF and tyrosine receptor kinase B (TrkB) were observed in the hippocampus and prefrontal cortex, compared with the CMS model group. Furthermore, increased expression levels of ERK, pERK, PI3K, Akt, and GSK3β were also detected in the hippocampus and prefrontal cortex of KXS-treated rats compared with CMS model rats and in primary hippocampal neuronal cells treated with KXS. These results suggest that pCREB and upstream components, including TrkB/ERK/CREB and TrkB/PI3 K/CREB, may contribute to the antidepressive effect induced by KXS. Further studies are required to confirm these findings.