Neuroprotective effect of muscone on glutamate-induced apoptosis in PC12 cells via antioxidant and Ca2+ antagonism

Muscone abrogates breast cancer progression through tumor angiogenic suppression via VEGF/PI3K/Akt/MAPK signaling pathways

BACKGROUND

Angiogenesis strongly reflects poor breast cancer outcome and an important contributor to breast cancer (BC) metastasis; therefore, anti-angiogenic intervention is a potential tool for cancer treatment. However, currently used antibodies against vascular endothelial growth factor A (VEGFA) or inhibitors that target the VEGFA receptor are not effective due to weak penetration and low efficiency. Herein, we assessed the anti-BC angiogenic role of muscone, a natural bioactive musk constituent, and explored possible anti-cancer mechanisms of this compound.

METHODS

CCK-8, EdU, scratch and Transwell assessments were employed to detect the muscone-mediated regulation of breast cancer (BC) and human umbilical vein endothelial cells (HUVECs) proliferation and migration. Tube formation, matrigel plug assay and zebrafish assay were employed for assessment of regulation of tumor angiogenesis by muscone. In vivo xenograft mouse model was constructed to compare microvessel density (MVD), vascular leakage, vascular maturation and function in muscone-treated or untreated mice. RNA sequencing was performed for gene screening, and Western blot verified the effect of the VEGFA-VEGFR2 pathway on BC angiogenic inhibition by muscone.

RESULTS

Based on our findings, muscone suppressed BC progression via tumor angiogenic inhibition in cellular and animal models. Functionally, muscone inhibited BC cell proliferation and migration as well as tumor cell-conditioned medium-based endothelial cell proliferation and migration. Muscone exhibited a strong suppressive influence on tumor vasculature in cellular and animal models. It abrogated tumor cell growth in a xenograft BC mouse model and minimized tumor microvessel density and hypoxia, and increased vascular wall cell coverage and perfusion. Regarding the mechanism of action, we found that muscone suppressed phosphorylation of members of the VEGF/PI3K/Akt/MAPK axis, and it worked synergistically with a VEGFR2 inhibitor, an Akt inhibitor, and a MAPK inhibitor to further inhibit tube formation.

CONCLUSION

Overall, our results demonstrate that muscone may proficiently suppress tumor angiogenesis via modulation of the VEGF/PI3K/Akt/MAPK axis, facilitating its candidacy as a natural small molecule drug for BC treatment.

Water extract of moschus alleviates erastin-induced ferroptosis by regulating the Keap1/Nrf2 pathway in HT22 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Moschus, first described in the Shennong's Classic of the Materia medicine, is a scarce and precious animal medicine. Modern pharmacological researches have suggested that Moschus has neuroprotective actions, and its mechanism is related to anti-inflammatory, antioxidant, and anti-apoptosis effects. Ferroptosis is one of the major pathologies of Alzheimer's disease (AD) and is widely implicated in the pathogenesis and progression of AD. Although previous studies have suggested that Moschus possesses neuroprotective effect, whether Moschus could mitigate neuronal damages by inhibiting the onset of ferroptosis is unknown in model cells of AD.

AIM OF THE STUDY

The aim of study was to explore the water extract of Moschus (WEM) on ferroptosis caused by erastin and the potential mechanism.

MATERIALS AND METHODS

Erastin was used to stimulate HT22 cells to form ferroptosis model to evaluate the anti-ferroptosis effect of WEM by cell counting kit-8 and lactic dehydrogenase (LDH) tests. The malondialdehyde (MDA) and glutathione (GSH) kits are used for detection of MDA and GSH levels, and 2',7'-dichlorofluorescein diacetate and C11 BODIPY 581/591 fluorescence probe are used for evaluation of reactive oxygen species (ROS) and lipid peroxide (LOOH) levels. And Western blot was used to test nuclear factor erythroid 2-related factor 2 (Nrf2), Kelch-like ECH-associated protein 1 (Keap1), heme oxygenase-1 (HO-1), and ferroptosis associated proteins including glutathione peroxidase 4 (GPX4), cystine/glutamate antiporter subunit (SLC7A11), ferritin heavy chain 1 (FTH1), ferroportin1 (FPN1), transferrin receptor (TFRC). In addition, the Nrf2 inhibitor ML385 was applied to verify whether WEM prevents erastin-induced ferroptosis by activating the Keap1/Nrf2 pathway.

RESULTS

After WEM treatment, erastin-induced HT22 cell survival was significantly elevated, the accumulation of intracellular MDA, ROS, and LOOH were significantly reduced, the level of GSH and expressions of ferroptosis inhibitors GPX4 and SLC7A11 were significantly increased, and iron metabolism-related proteins TFRC, FPN1, and FTH1 were regulated. These effects of WEM are implemented by activating the Keap1/Nrf2 pathway.

CONCLUSIONS

This study demonstrated that WEM could perform neuroprotective effects by alleviating ferroptosis, verified that WEM treatment of AD can be mediated by the Keap1/Nrf2 pathway, and provided theoretical support for the application of WEM in the treatment of AD.

Muscone alleviates neuronal injury via increasing stress granules formation and reducing apoptosis in acute ischemic stroke

As the main bioactive component of musk, muscone has been reported to have marked protective effects in treating acute ischemic stroke (AIS). However, the specific anti-stroke mechanism of muscone still needs further research. In the current investigation, the PC12 cells OGD/R and the rat transient MCAO/R models were utilized as the AIS models. Serum hepatic and renal functional indexes (ALT, AST, BUN, and Cr) and cell viability were determined to select the appropriate muscone concentrations for in vitro and in vivo experiments. TTC, Hematoxylin and eosin (H&E), and Live/Dead staining were utilized to evaluate the protective effects of muscone in injured tissues and cells. Western blotting analysis, TUNEL staining, propidium iodide, and annexin V staining were applied to detect the anti-apoptotic effect of muscone. Double-label immunofluorescence staining of T-cell intracellular antigen-1 (TIA1) and Ras-GAP SH3 domain-binding protein 1 (G3BP1) was performed to observe whether muscone regulated the SG formation level. Molecular docking, TIA1 silencing and TIA1 overexpression experiments were employed to investigate the molecular mechanism underlying the regulation of SG formation by muscone. The 2, 3, 5-Triphenyl-tetrazolium chloride (TTC) staining and live/dead staining showed the AIS injury level of MCAO/R rat and the OGD/R PC12 cells were attenuated by muscone administration. The muscone significantly minimized the apoptosis rate in MCAO/R rats and OGD/R PC12 cells following flow cytometry analysis, western blotting analysis, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The double-label immunofluorescence staining data revealed that muscone promoted the SG formation level in OGD/R PC12 cells and the cortex MCAO/R rats. The results of molecular docking, TIA1 silencing and TIA1 overexpression experiments revealed that muscone could bind to TIA1 protein and regulate its expression level, thereby promoting the formation of stress granules and exerting a protective effect against AIS injury. This study indicated that the significant protective effect of muscone in reducing apoptosis levels might be via promoting SG formation under AIS conditions. This study further explores the therapeutic effect and anti-apoptosis mechanism of muscone in AIS, which may provide a potential candidate drug for the clinical treatment of AIS injury.

Cholinergic signaling of muscarinic receptors directly involves in the neuroprotection of muscone by inducing Ca2+ antagonism and maintaining mitochondrial function

ETHNOPHARMACOLOGICAL RELEVANCE

Musk, a traditional Chinese medicine, is broadly used in inducing resuscitation and refreshing the mind, activating blood and alleviating pain. It is commonly used for the treatment of ischemic stroke, and muscone is its core medicinal component.

AIM OF THE STUDY

The aim of this study was to explore whether muscone ameliorates neuronal damage through cholinergic signaling of muscarinic receptors.

MATERIALS AND METHODS

The effects of muscone were tested in a rat model of middle cerebral artery occlusion (MCAO) as well as injured neurons induced by oxygen-glucose deprivation (OGD) in PC12 cells. Cell counting kit 8 (CCK8) assay was used to measure the cell viability, and the production of lactate dehydrogenase (LDH) and adenosine-triphosphate (ATP) were examined by kit. 2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA), tetramethylrhodamine ethyl ester (TMRE) and Fluo-4 acetoxymethyl ester (Fluo-4 AM) staining were used to demonstrate effect of muscone on the reactive oxygen species (ROS) level, mitochondria membrane potential (MMP) and intracellular Ca2+ measurement in cells respectively, in which all of those staining was visualized by laser confocal microscope. For in vivo experiments, rats' cerebral blood flow was measured using laser Doppler blood flowmetry to evaluate the MCAO model, and a modified neurological severity score (mNSS) was used to assess the recovery of neurological function. Calculate infarct rate was measured by 2,3,5-Triphenyl Tetrazolium Chloride (TTC) staining. Except DCFH-DA and Fluo-4 AM staining, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl benzimidazolylcarbocyanine iodide (JC-1) staining was used to observe intracellular Ca2+ measurement in brain cells. Protein levels in cells and tissues were detected by Western blot.

RESULTS

Pretreatment with muscone significantly improved the cell viability, lactic acid production, mitochondrial membrane potential collapse and function, Ca2+ overload, ROS generation, and cell apoptosis in OGD PC12 cells. Muscone also regulated PI3K, ERK and AKT signal pathways by activating cholinergic signaling of muscarinic receptors in PC12 cells induced with OGD. More importantly, the blocking of cholinergic signaling of muscarinic receptors by atropine significantly reduces the neuroprotective effects of muscone, including the cell viability, Ca2+ efflux, and mitochondrial repair. Furthermore, muscone was found to effectively alleviate mitochondrial dysfunction and elevated levels of ROS induced by the MCAO in the brain tissue. Notably, this beneficial effect of muscone was attenuated by atropine but not by (+)-Sparteine.

CONCLUSIONS

Our study indicates that muscone exerts its neuroprotective effects by activating muscarinic receptors of cholinergic signaling, thus providing a promising therapeutic target for the treatment of OGD-induced nerve injury in stroke. The findings suggest that these treatments may hold potential benefits for stroke patients.

Moschus ameliorates glutamate-induced cellular damage by regulating autophagy and apoptosis pathway

Alzheimer's disease (AD), a neurodegenerative disorder, causes short-term memory and cognition declines. It is estimated that one in three elderly people die from AD or other dementias. Chinese herbal medicine as a potential drug for treating AD has gained growing interest from many researchers. Moschus, a rare and valuable traditional Chinese animal medicine, was originally documented in Shennong Ben Cao Jing and recognized for its properties of reviving consciousness/resuscitation. Additionally, Moschus has the efficacy of "regulation of menstruation with blood activation, relief of swelling and pain" and is used for treating unconsciousness, stroke, coma, and cerebrovascular diseases. However, it is uncertain whether Moschus has any protective effect on AD patients. We explored whether Moschus could protect glutamate (Glu)-induced PC12 cells from cellular injury and preliminarily explored their related action mechanisms. The chemical compounds of Moschus were analyzed and identified by GC-MS. The Glu-induced differentiated PC12 cell model was thought to be the common AD cellular model. The study aims to preliminarily investigate the intervention effect of Moschus on Glu-induced PC12 cell damage as well as their related action mechanisms. Cell viability, lactate dehydrogenase (LDH), mitochondrial reactive oxygen species, mitochondrial membrane potential (MMP), cell apoptosis, autophagic vacuoles, autolysosomes or autophagosomes, proteins related to apoptosis, and the proteins related to autophagy were examined and analyzed. Seventeen active compounds of the Moschus sample were identified based on GC-MS analysis. In comparison to the control group, Glu stimulation increased cell viability loss, LDH release, mitochondrial damage, loss of MMP, apoptosis rate, and the number of cells containing autophagic vacuoles, and autolysosomes or autophagosomes, while these results were decreased after the pretreatment with Moschus and 3-methyladenine (3-MA). Furthermore, Glu stimulation significantly increased cleaved caspase-3, Beclin1, and LC3II protein expression, and reduced B-cell lymphoma 2/BAX ratio and p62 protein expression, but these results were reversed after pretreatment of Moschus and 3-MA. Moschus has protective activity in Glu-induced PC12 cell injury, and the potential mechanism might involve the regulation of autophagy and apoptosis. Our study may promote research on Moschus in the field of neurodegenerative diseases, and Moschus may be considered as a potential therapeutic agent for AD.

Correlation Analysis between Muskrat (Ondatra zibethicus) Musk and Traditional Musk

Muskrat musk is considered to be a potential substitute for traditional musk. However, little is known about the similarity between muskrat musk and musk, and whether it is related to muskrat age. In this study, muskrat musk (MR1, MR2, and MR3) were from 1, 2, and 3-year-old muskrats, respectively, and white musk (WM) and brown musk (BM) were picked from male forest musk deer. The results indicated that muskrat musk had higher similarity to WM than BM. Further research showed that RM3 had the highest matched degree with WM. By significantly different metabolite analysis, we found that 52 metabolites continue to increase from 1- to 3-year-old muskrats. In total, 7 and 15 metabolites were significantly decreased in RM1 vs. RM2 and RM2 vs. RM3, respectively. Meanwhile, 30 and 17 signaling pathways were observed from increased and decreased metabolites, respectively. The increased metabolites mainly entailed enrichment in amino acid biosynthesis and metabolism, steroid hormone biosynthesis, and fatty acid biosynthesis. In conclusion, muskrat musk from three-year-old muskrat is a relatively good substitute for white musk, and the result also implies that these biological processes of amino acid biosynthesis and metabolism, steroid hormone biosynthesis, and fatty acid biosynthesis are beneficial to the secretion of muskrat musk.

Muscone promotes functional recovery by facilitating microglia polarization into M2 phenotype through PPAR-γ pathway after ischemic stroke

Exploring regimens to facilitate microglia transformation from M1 to M2 phenotype is a feasible strategy to suppress neuroinflammation, therefore reinforcing functional recovery after ischemic stroke. Muscone easily crosses the blood brain barrier (BBB) and distributes throughout the brain. Here, the results illustrated the administration of 8 mg/kg muscone promoted functional recovery through reducing the infarct volume by 2,3,5-triphenyltetrazolium chloride (TTC) staining after ischemic stroke in mice. Then, the expression of pro-inflammatory factors, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6), was significantly decreased, whereas the level of anti-inflammatory agents including C-X-C Motif Chemokine Ligand 1 (CXCL1), transforming growth factor-β (TGF-β) and interleukin-10 (IL-10) was obviously elevated in penumbra with the treatment of 8 mg/kg muscone using real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), western blot and enzyme-linked immunosorbent assay (ELISA) tests. Subsequently, the results showed the application of muscone upregulated the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) to facilitate microglia transformation into M2 phenotype using RT-qPCR, western blot and immunofluorescence analysis. Collectively, the present study provides evidence for our hypothesis that muscone intensifies microglia transformation into M2 phenotype via activating PPAR-γ signaling pathway in penumbra after ischemic stroke. These findings demonstrate muscone is a promising candidate for the treatment of ischemic stroke.

Shenxiong glucose injection inhibits oxidative stress and apoptosis to ameliorate isoproterenol-induced myocardial ischemia in rats and improve the function of HUVECs exposed to CoCl2

Background: Shenxiong Glucose Injection (SGI) is a traditional Chinese medicine formula composed of ligustrazine hydrochloride and Danshen (Radix et rhizoma Salviae miltiorrhizae; Salvia miltiorrhiza Bunge, Lamiaceae). Our previous studies and others have shown that SGI has excellent therapeutic effects on myocardial ischemia (MI). However, the potential mechanisms of action have yet to be elucidated. This study aimed to explore the molecular mechanism of SGI in MI treatment. Methods: Sprague-Dawley rats were treated with isoproterenol (ISO) to establish the MI model. Electrocardiograms, hemodynamic parameters, echocardiograms, reactive oxygen species (ROS) levels, and serum concentrations of cardiac troponin I (cTnI) and cardiac troponin T (cTnT) were analyzed to explore the protective effect of SGI on MI. In addition, a model of oxidative damage and apoptosis in human umbilical vein endothelial cells (HUVECs) was established using CoCl₂. Cell viability, Ca²⁺ concentration, mitochondrial membrane potential (MMP), apoptosis, intracellular ROS, and cell cycle parameters were detected in the HUVEC model. The expression of apoptosis-related proteins (Bcl-2, Caspase-3, PARP, cytoplasmic and mitochondrial Cyt-c and Bax, and p-ERK1/2) was determined by western blotting, and the expression of cleaved caspase-3 was analyzed by immunofluorescence. Results: SGI significantly reduced ROS production and serum concentrations of cTnI and cTnT, reversed ST-segment elevation, and attenuated the deterioration of left ventricular function in ISO-induced MI rats. In vitro, SGI treatment significantly inhibited intracellular ROS overexpression, Ca²⁺ influx, MMP disruption, and G2/M arrest in the cell cycle. Additionally, SGI treatment markedly upregulated the expression of anti-apoptotic protein Bcl-2 and downregulated the expression of pro-apoptotic proteins p-ERK1/2, mitochondrial Bax, cytoplasmic Cyt-c, cleaved caspase-3, and PARP. Conclusion: SGI could improve MI by inhibiting the oxidative stress and apoptosis signaling pathways. These findings provide evidence to explain the pharmacological action and underlying molecular mechanisms of SGI in the treatment of MI.

Research progress on mechanism of Chinese Kaiqiao herbs in management of neuropathic pain

The Chinese herbal medicine for Kaiqiao, such as borneol, musk, grassleaf sweetflag rhizome, storax and camphor, have been prescribed in traditional Chinese medicine for thousands of years and now are widely used for neuropathic pain, the main components of which are annular compounds. Studies have shown that their analgesic mechanisms include regulating the expression of γ-aminobutyric acid, N-methyl- D-aspartic acid and other receptors; regulating ion channel function; inhibiting inflammatory response, oxidative stress and apoptosis; regulating neurotransmission and neuronal excitability; and participating in neuroprotection and neurological repair. It is suggested that the mechanisms of action of Kaiqiao herbs in central nervous system analgesia should be further explored; high-quality rapid screening of drug targets may be used, and the targeted agents using the characteristics of Kaiqiao herbs would be developed. This article reviews the research progress on the effect mechanism of traditional Kaiqiao herbs in the treatment of neuropathic pain to provide further research directions.

Proteomics on the role of muscone in the "consciousness-restoring resuscitation" effect of musk on ischemic stroke

ETHNOPHARMACOLOGICAL RELEVANCE

Musk is a representative drug of aroma-relieving traditional Chinese medicine, and it is a commonly used traditional Chinese medicine for the treatment of ischemic stroke. Muscone is the core medicinal component of musk.

AIM OF THE STUDY

We sought to identify the target of muscone in the treatment of ischemic stroke using network pharmacology, an animal model of ischemic stroke, and differential proteomics.

MATERIALS AND METHODS

The drug targets of muscone in the treatment of ischemic stroke were predicted and analyzed using information derived from sources such as the Traditional Chinese Medicine Systems Pharmacology database and Swiss Target Prediction tool. The animal model of focal cerebral ischemia was established by suture-based occlusion of the middle cerebral artery of rats. The rats were divided into six groups: sham-operated control, model, musk, muscone1, muscone2, and muscone3. Neurological deficit scores were calculated after intragastric administration of musk or muscone. The microcirculation blood flow of the pia mater was detected using a laser speckle blood flow meter. The cerebral infarction rate was detected by 2,3,5-triphenyltetrazolium chloride staining. The necrosis rate of the cerebral cortex and the hippocampal neurons was detected by hematoxylin and eosin staining. Blood-brain barrier damage was detected by the Evans blue method. Quantitative proteomics analysis in the sham-operated control, model, and muscone groups was performed using tandem-mass-tags. Considering fold changes exceeding 1.2 as differential protein expression, the quantitative values were compared among groups by analysis of variance. Furthermore, a protein-protein interaction network was constructed, and differentially expressed proteins were analyzed by gene ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis.

RESULTS

Network pharmacology identified 339 targets for the intersection of 17 components of musk and cerebral ischemia-reperfusion injury. The GO and KEGG enrichment items mainly identified regulation of neuronal synaptic structure and transfer function, synaptic neurotransmitters, and receptor activity. Zoopery showed that the model group had a higher behavioral score, cerebral infarction rate, cortical and hippocampal neuron death rate, Evans blue exudation in the brain, and bilateral pia mater microcirculation blood flow differences than the sham-operated control group (P <0.01). Compared with the model group, the behavioral score, infarction rate, hippocampal neuronal mortality, and Evans blue content decreased significantly in the musk, muscone2, and muscone3 groups (P <0.05). Proteomic analysis showed that 160 genes were differentially expressed among the sham-operated control, model, and muscone groups. GO items with high enrichment included neuronal synapses, postsynaptic signal transduction, etc. KEGG items with high enrichment included cholinergic synapses, calcium signaling pathway, dopaminergic synapses, etc. Protein interaction analysis revealed that the top three protein pairs were Ndufa10/Ndufa6, Kcna2/Kcnab2, and Gsk3b/Traf6.

CONCLUSIONS

Muscone can reduce neuronal necrosis, protect the blood-brain barrier, and improve the neurological damage caused by cerebral ischemia via molecular mechanisms mainly involving the regulation of neuronal synaptic connections. Muscone is an important active component responsible for the "consciousness-restoring resuscitation" effect of musk on ischemic stroke.

Muscone suppresses myocardial ischemia damage by regulating PI3K/Akt signaling pathway

Muscone is the main active compound of Moschus. In this paper, the cardioprotective effect of Muscone on acute myocardial ischemia (AMI) rats and its potential mechanisms were investigated. AMI rat models were established to evaluate the protective effect and antioxidative function of Muscone on the hearts. Moreover, Western blot analysis was conducted to quantify the phosphorylated PI3K and AKT levels in PI3K/Akt pathway for further investigating the mechanism of Muscone. Results showed that Muscone could markedly lessen the infarct size and myocardial injury, improve cardiac function, inhibit cardiomyocyte apoptosis and down-regulate serum reactive oxygen species level as indicated by the decreased MDA, BNP and c-TnI activities and the increased SOD, GSH-px, CAT activities and the expression of Bax protein. In addition, it was revealed that Muscone notably promoted the phosphorylation of PI3K and AKT. These findings denote that Muscone exerts a protective effect in heart via inhibition of oxidative stress and apoptosis, offering new insights into the treatment of CHD and the clinical application of Muscone.

Comprehensive chemical profiling of volatile constituents of Angong Niuhuang Pill in vitro and in vivo based on gas chromatography coupled with mass spectrometry

Background

Angong Niuhuang Pill (ANP), a renowned precious traditional Chinese medicine prescription, is extensively utilized for the clinical treatment of stroke, meningitis and encephalorrhagia in China. As a classic resuscitation-inducing aromatic prescription, ANP has been investigated for its pharmacological effects in recent years, while the volatile composition in ANP still lacks comprehensive elucidation.

Method

To better explore the volatile constituents in ANP, a qualitative analysis method was developed based on gas chromatography coupled with mass spectrometry. Furthermore, a validated quantitative method was established to determine 21 main compounds in 8 batches of commercially available ANP samples by gas chromatography-tandem mass spectrometry. The quantitative data were successively subjected to Pearson correlation coefficient analysis. Additionally, the absorbed volatile constituents in rat plasma after single oral administration of ANP have also been characterized.

Results

A total of 93 volatile constituents including 29 sesquiterpenoids, 28 monoterpenoids, 13 fatty acids and their esters, 7 alkanes, 6 ketones, 3 phenols, 3 aldehydes, 2 benzoate esters, and 2 other types, were preliminarily characterized, which primarily originated from Borneolum, Moschus, Curcumae Radix, and Gardeniae Fructus. d-Borneol, isoborneol and muscone were the top three abundant ingredients (> 600 μg/g) in 8 batches of ANP samples. Subsequently, the average Pearson correlation coefficient of the contents of 21 analytes was 0.993, inferring the high batch-to-batch similarity among 8 batches. After oral administration of ANP, d-borneol, isoborneol, muscone and camphor were the main volatile constituents absorbed in the rat plasma.

Conclusion

This research may be helpful for the comprehensive quality control study of ANP, and provide for guarantee the clinical efficacy of ANP.

Protective role of muscones on astrocytes under a mechanical-chemical damage model

Background

Traumatic spinal cord injury (SCI) is a major clinical concern and a life-changing neurological condition with substantial socioeconomic implications. The initial mechanical force applied to the spinal cord at the time of injury is known as the primary injury. After the primary injury, ischemia and hypoxia induce cell death and autolysis, which are associated with the release of a group of inflammatory factors and biologically active substances, such as superoxide dismutase (SOD), malonaldehyde (MDA), lactate dehydrogenase (LDH), and tumor necrosis factor-α (TNF-α). These processes are called the secondary injury, and may lead to an excess of extracellular glutamate (Glu), which in turn promotes the neuronal injuries. Muscone has been shown to have anti-inflammatory effects in the treatment of brain diseases and other diseases. However, to date, no study has examined the effects of muscone in the treatment of SCI.

Methods

Astrocytes were separated and purified by the method of short-term exposure combining with differential sticking wall. Astrocyte was identified by glial fibers acidic protein (GFAP) selecting cell immunochemical staining. A mechanical-chemical damage (MCD) model was established via the primary spinal astrocytes of rats, and treatment was administered with different concentrations of muscone. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT) was detected at 6, 12, 24, 48 and 72 h. SOD, MDA, LDH, TNF-alpha and intracellular calcium was detected at 3, 6 and 12 h. Glu in supernatant was detected respectively at 3, 6 and 12 h by enzyme-linked immunosorbent assay (ELISA) method. Intracellular calcium was detected respectively at 3, 6 and 12 h by flow cytometry method. MRNA expression of excitatory amino acid transporters (EAATs) and GFAP were detected by the quantitative reverse transcription polymerase chain reaction (qRT-PCR) method and protein expression of those by western blot at 6 h.

Results

Muscone reduced the levels of LDH, TNF-α, and MDA after injury, and upregulated the level of SOD. Muscone also reduced the density of extracellular Glu and suppressed the intracellular calcium level. Additionally, it decreased the expression levels of EAATs and GFAPs.

Conclusions

Muscone has a protective effect on astrocytes in a MCD and inhibits astrocytes’ proliferation.

Muscone Can Improve Spinal Cord Injury by Activating the Angiogenin/Plexin-B2 Axis

Spinal cord injury (SCI) is a devastating neurological disorder that usually damages sensorimotor and autonomic functions. Signaling pathways can play a key role in the repair process of SCI. The plexin-B2 acts as a receptor for angiogenin and mediates ribosomal RNA transcription, influencing cell survival and proliferation. Protein kinase B serine/threonine kinase interacts with angiogenin to form a positive feedback effect. Brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor can induce angiogenin nuclear translocation. Moreover, the BDNF can promote the secretion of angiogenin. Interestingly, all of them can activate the angiogenin/plexin-B2 axis. Muscone has anti-inflammatory and proliferative features as it can inhibit nuclear transcription factor kappa-B (NF-κB) and activate the angiogenin/plexin-B2 axis, thus being significant agent in the SCI repair process. Herein, we review the potential mechanism of angiogenin/plexin-B2 axis activation and the role of muscone in SCI treatment. Muscone may attenuate inflammatory responses and promote neuronal regeneration after SCI.

Protective effects of muscone on traumatic spinal cord injury in rats

Background

Traumatic spinal cord injury (SCI) is a major clinical concern, and it is a life-changing neurological condition with substantial socioeconomic implications. Muscone has been widely used in traditional Chinese medicinal formulations for its anti-inflammatory activity. However, its protective effects on traumatic SCI have not been explored. This study investigated whether muscone plays a protective role in SCI and compared its effects with those of methylprednisolone sodium succinate (MPSS).

Methods

Rats were divided into five groups: normal saline (NS; n=24), methylprednisolone (MP; w=24), and muscone 1 (MO1), muscone 2 (MO2), and muscone 3 (MO3) (n=24 in each group, collectively called the MOx groups). The SCI rat model was established by the modified Allen's method. The rats were administered muscone (MO1: 2.5 mg/kg, MO2: 5 mg/kg, and MO3: 10 mg/kg) or MP (30 mg/kg), or an equivalent volume of saline. The rats were kept under observation for 4 weeks. Malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor-alpha (TNF-α) levels were detected using enzyme-linked immunosorbent assay (ELISA). The expression of glial fibrillary acidic protein (GFAP), B-cell lymphoma-2 (BCL-2), and caspase3 was detected by western blot analysis. Hematoxylin-eosin (HE), Nissl, and immunocytochemistry (ICC) staining was performed for pathological observation. Basso-Beattie-Bresnahan motor function scores were evaluated for assessment of neural functions after acute SCI.

Results

Muscone inhibited immune-inflammatory reactions, neuronal necrosis, and apoptosis. The lower limb function recovery was better in the MOx groups compared with NS and MP groups according to Basso-Beattie-Bresnahan scores. The changes were remarkable in the MO2 group compared with the other groups.

Conclusions

Muscone alleviates secondary injury after SCI by reducing immune-inflammatory reactions, neuronal necrosis, and apoptosis.

Chemical compositions and pharmacological activities of natural musk (Moschus) and artificial musk: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Natural musk (Moschus), derived naturally from male musk deer (Moschus berezovskii Flerov, Moschus sifanicus Przewalski, or Moschus moschiferus Linnaeus), has long been an important component of traditional Chinese medicine (TCM), and was used as resuscitation, blood circulation, and collateral drainage. detumescence and pain relief. Artificial musk was researched and applied into TCM as natural musk being as unsustainable resources.

AIM OF THE STUDY

We mainly summarized chemical compositions, pharmacological activities and mechanism of action of natural and artificial musk, and designed to serve as a foundation for further research into musk chemical compositions and pharmacological effect.

MATERIALS AND METHODS

Those mainstream scientific databases including Google Scholar, ScienceDirect, SpringerLink, CNKI, Wiley Online Library, web of science, were used for searching with below "Keywords", as well as literature-tracking. Literatures spanned 1962 to 2021, and involved into Chinese, English, Janpanese, Korean.

RESULTS

Natural musk contains some very desirable but scarce compounds, as well as their biological features, which led to the development of artificial musk. The chemical ingredients, pharmacological activities, and mechanisms of action of natural and artificial musk are summarized and compared in this paper. Polypeptide and protein, muscone, musclide, steroids, muscopyridine, and other chemical constituents of musk demonstrated important therapeutic properties against inflammation, immune system disorders, neurological disorders, cardiovascular system disorders, and so on. The mechanism of action contributed to effect on mediators, acceptors and relative signal pathways.

CONCLUSIONS

Natural and artificial musk were revealed having some activated compounds, and showed excellent pharmacological effect. Meantime, above two sides of natural and artificial musk ought to get further research.

Zoology, chemical composition, pharmacology, quality control and future perspective of Musk (Moschus): a review

Musk, the dried secretion from the musk sac gland which is located between the navel and genitals of mature male musk deer, is utilized as oriental medicine in east Asia. It has been utilized to treat conditions such as stroke, coma, neurasthenia, convulsions, and heart diseases in China since ancient times. This paper aims to provide a comprehensive overview of musk in zoology, chemical composition, pharmacology, clinical applications, and quality control according to the up-to-date literature. Studies found that musk mainly contains macrocyclic ketones, pyridine, steroids, fatty acids, amino acids, peptides, and proteins, whilst the main active ingredient is muscone. Modern pharmacological studies have proven that musk possesses potent anti-inflammatory effects, neuroprotective effects, anti-cancer effects, antioxidant effects, etc. Moreover, muscone, the main active ingredient, possesses anti-inflammatory, neuroprotective, antioxidant, and other pharmacological effects. In the quality control of musk, muscone is usually the main detection indicator, and the common analytical method is GC, and researchers have established novel and convenient methods such as HPLC-RI, RP-UPLC-ELSD, and Single-Sweep Polarography. In addition, quality evaluation methods based on steroids and the bioactivity of musk have been established. As for the identification of musk, due to various objective factors such as the availability of synthetic Muscone, it is not sufficient to rely on muscone alone as an identification index. To date, some novel technologies have also been introduced into the identification of musk, such as the electronic nose and DNA barcoding technology. In future research, more in vivo experiments and clinical studies are encouraged to fully explain the pharmacological effects and toxicity of musk, and more comprehensive methods are needed to evaluate and control the quality of musk.

Pharmacological effects and mechanisms of muscone

Musk, the dried secretion from the preputial follicles of the male musk deer (genus Moschus), possesses various pharmacological activities and has been used extensively in traditional Chinese medicine for thousands of years. Muscone is the main active ingredient of musk and exerts pharmacological effects similar to those of musk. Although muscone was notably used to treat various disorders and diseases, such as neurological disorders, chronic inflammation and ischemia-reperfusion injury, most of the mechanisms of the pharmacological action of muscone remain unclear because of slow progress in research before the 21st century. In recent years, the pharmacological activities and mechanisms of muscone have been clarified. The present article summarizes the pharmacological and biological studies on cerebrovascular disease, cardiovascular disease, neurological effects, cancer and others and the associated mechanisms of the action of muscone to date.

Neuroprotective effects of natural compounds on neurotoxin-induced oxidative stress and cell apoptosis

OBJECTIVES

Overproduction of reactive species, notably reactive oxygen (ROS) and nitrogen (RNS) species, along with the failure of balancing effects of endogenous antioxidant defenses result in destruction of cellular structures, lipids, proteins, and genetic material, which lead to oxidative stress. Oxidative stress-induced neuronal apoptosis plays a pivotal role in pathogenesis of neurodegeneration. Antioxidants represent one of the medical choice strategies for protecting against this unbalanced oxidation-antioxidation status. Recently, natural compounds with neuroprotective potential that can scavenge free radicals and protect cells from oxidative damage have received extensive attention.

METHODS

In this review, we summarized the detailed research progress on the medicinal plants-derived natural compounds with potential anti-oxidation effects and their molecular mechanisms on modulating the neurotoxin (6-OHDA, H₂O₂, glutamate, Aβ)-induced oxidative stress and cell apoptosis.

RESULTS

The natural compounds that efficacious in modulating reactive species production and mitochondrial function include flavonoids, glucosides, alkaloids, polyphenols, lignans, coumarins, terpenoids, quinones and others. They decreased the neurotoxin-induced oxidative damage and apoptosis by (1) decreasing ROS/RNS generation, lipid peroxidation, caspase-3 and caspase-9 activities, LDH release, the ratio of Bax/Bcl-2, Ca²⁺ influx and cytochrome c release, (2) elevating MMP, and (3) restoring endogenous antioxidant enzymatic activities (CAT, GSH-Px, GSR, SOD). And they exerted neuroprotective effects against cell damages and apoptosis by modulating the oxidative cascades of different signaling pathways (Nrf2/HO-1, NF-κB, MAPKs, PI3K/Akt, GSK-3β) and preventing mitochondria-dependent apoptosis pathways.

DISCUSSION

The present work reviews the role of oxidative stress in neurodegeneration, highlighting the potential anti-oxidation effects of natural compounds as a promising approach to develop innovative neuroprotective strategy.

Preventive Effect of Muscone against Cisplatin Nephrotoxicity in LLC-PK1 Cells

Cisplatin, one of the most common antitumor agents, is widely applied to treat various cancerous diseases and is included in the World Health Organization Model List of Essential Medicines. Cisplatin therapy is used to treat 10-20% of all cancerous cases, and its cure rate is especially high in testicular cancer (over 90%). However, a major side effect of this anticancer drug is nephrotoxicity, limiting treatment effect and reducing the quality of life in cancer patients. Muscone, an odoriferous constituent of musk, was confirmed to inhibit cisplatin-induced LLC-PK1 kidney proximal tubule cell death in a dose-dependent manner. In term of renal protective mechanism, muscone inhibited cisplatin oxidative toxicity by decreasing reactive oxygen species (ROS) level and stimulating HO-1 expression. Muscone also exerted anti-inflammation effect through inhibition of p38 phosphorylation. Furthermore, muscone mitigated cisplatin-induced apoptosis in LLC-PK1 cells via both intrinsic and extrinsic pathways by inhibiting pro-apoptotic protein Bax expression, and cleaved caspase-3, 7, and 8; and increase of anti-apoptotic protein Bcl-2 level. In addition, the anti-apoptotic effect of muscone also was enhanced by preventing p53 expression and its phosphorylation. Our study showed that muscone may be a potential protective agent against cisplatin-induced nephrotoxicity.

Dexmedetomidine Attenuates Glutamate-Induced Cytotoxicity by Inhibiting the Mitochondrial-Mediated Apoptotic Pathway

Background

Glutamate (GLU) is the most excitatory amino acid in the central nervous system and plays an important role in maintaining the normal function of the nervous system. During cerebral ischemia, massive release of GLU leads to neuronal necrosis and apoptosis. It has been reported that dexmedetomidine (DEX) possesses anti-oxidant and anti-apoptotic properties. The objective of this study was to investigate the effects of DEX on GLU-induced neurotoxicity in PC12 cells.

Material/Methods

PC12 cells were treated with 20 mM GLU to establish an ischemia-induced injury model. Cell viability was accessed by MTT assay. MDA content and SOD activity were analyzed by assay kits. Apoptosis rate, ROS production, intracellular Ca²⁺ concentration, and MMP were evaluated by flow cytometry. Western blot analysis was performed to analyze expressions of caspase-3, caspase-9, cyt-c, bax, and bcl-2.

Results

PC12 cells treated with GLU exhibited reduced cell viability and increased apoptosis rates, which were ameliorated by pretreatment with DEX. DEX significantly increased SOD activity, reduced content of MDA, and decreased production of ROS in PC12 cells. In addition, DEX clearly reduced the level of intracellular Ca²⁺ and attenuated the decline of MMP. Moreover, DEX notably reduced expressions of caspase-3, caspase-9, cyt-c, and bax and increased expression of bcl-2.

Conclusions

Our findings suggest that DEX can protect PC12 cells against GLU-induced cytotoxicity, which may be attributed to its anti-oxidative property and reduction of intracellular calcium overload, as well as its ability to inhibit the mitochondria-mediated apoptotic pathway.

Muscone suppresses inflammatory responses and neuronal damage in a rat model of cervical spondylotic myelopathy by regulating Drp1-dependent mitochondrial fission

Cervical spondylotic myelopathy (CSM) is a common cause of disability with few treatments. Aberrant mitochondrial dynamics play a crucial role in the pathogenesis of various neurodegenerative diseases. Thus, regulation of mitochondrial dynamics may offer therapeutic benefit for the treatment of CSM. Muscone, the active ingredient of an odoriferous animal product, exhibits anti-inflammatory and neuroprotective effects for which the underlying mechanisms remain obscure. We hypothesized that muscone might ameliorate inflammatory responses and neuronal damage by regulating mitochondrial dynamics. To this end, the effects of muscone on a rat model of chronic cervical cord compression, as well as activated BV2 cells and injured neurons, were assessed. The results showed that muscone intervention improved motor function compared with vehicle-treated rats. Indeed, muscone attenuated pro-inflammatory cytokine expression, neuronal-apoptosis indicators in the lesion area, and activation of the nod-like receptor family pyrin domain-containing 3 inflammasome, nuclear transcription factor-κB, and dynamin-related protein 1 in Iba1- and βIII-tubulin-labeled cells. Compared with vehicle-treated rats, compression sites of muscone-treated animals exhibited elongated mitochondrial morphologies in individual cell types and reduced reactive oxygen species. In vitro results indicated that muscone suppressed microglial activation and neuronal damage by regulating related-inflammatory or apoptotic molecules. Moreover, muscone inhibited dynamin-related protein 1 activation in activated BV2 cells and injured neurons, whereby it rescued mitochondrial fragmentation and reactive oxygen species production, which regulate a wide range of inflammatory and apoptotic molecules. Our findings reveal that muscone attenuates neuroinflammation and neuronal damage in rats with chronic cervical cord compression by regulating mitochondrial fission events, suggesting its promise for CSM therapy.

Coniferyl ferulate exerts antidepressant effect via inhibiting the activation of NMDAR-CaMKII-MAPKs and mitochondrial apoptotic pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaoyaosan (XYS), composed of Radix Bupleuri, Radix Angelicae Sinensis, Radix Paeoniae Alba, Rhizoma Atractylodis Macrocephalae, Poria, Herba Menthae, Rhizoma Zingiberis Recens and Radix Glycyrrhizae, is a valuable traditional Chinese medicine (TCM) which is used for the treatment of depression in China. In our previous experiments, we found that coniferyl ferulate (CF) was the main active constituent of Xiaoyaosan based on UPLC-PDA guided isolation technique. However, the antidepressant effect and mechanisms of CF is still unknown.

AIM OF THE STUDY

In the current study, we aim to explore the possible mechanisms involved in the neuroprotective effect of CF in glutamate-injured PC12 cells, and further to confirm the anti-depressant effect of CF on the model of behavioral despair in vivo.

MATERIAL AND METHODS

The model of glutamate-injured PC12 cells was employed to investigate the possible mechanisms involved in the neuroprotective effect of CF. The model of behavioral despair was carried out to examine the in vivo anti-depressant effect of CF.

RESULTS

The results showed that CF significantly attenuated the decrease of cell viability, the release of lactate dehydrogenase (LDH), and the increase of apoptosis rates induced by glutamate. CF could also suppress the influx of Ca²⁺ and the elevation of p-NR2B, p-CaMK II, p-JNK, and p-p38 level induced by glutamate. Besides, CF could also inhibit the generation of reactive oxygen species (ROS), the decrease of SOD activity, the elevation of malondialdehyde (MDA) level, and suppress the loss of mitochondrial membrane potential (MMPs) and the activation Bcl-2/Bax mediated apoptotic pathways induced by glutamate. Furthermore, CF obviously decreased the immobility time in tail suspension test (TST) and forced swimming test (FST).

CONCLUSION

In conclusion, CF exert the indeed anti-depressant effect. The inhibition of NMDAR-CaMKII-MAPKs signaling pathway, oxidative stress, and mitochondrial apoptotic pathways were involved in the anti-depressant effect of CF.

Muscone reduced the hypnotic and analgesic effect of ketamine in mice

BACKGROUND

The aim of this study was to determine the effects of different concentrations of muscone on the ketamine requirement for hypnosis and analgesia and possible mechanism in mice.

METHODS

In the hypnotic response experiment, muscone (0.5, 1.0, 2.0, 4.0, and 8.0 mg/kg) was administered 15 minutes before ketamine by intraperitoneal injection. The hypnotic response was evaluated by loss of righting reflex (LORR). In the analgesia experiment, muscone (0.5, 1.0, 2.0, and 4.0 mg/kg) was administered 15 minutes before 50 mg/kg ketamine injection. Pain threshold was assessed by measuring the tail-flick latency induced by heat radiation. Twenty minutes after ketamine injection, the mRNA expression of N-methyl-D-aspartate receptors (NR) subunits, γ-aminobutyric acid (GABA) receptors subunits, opioid receptors subunits, and some Na and Ca channels were detected by qPCR in the hippocampus of mice.

RESULTS

The 50% effective dose (ED50) with 95% confidence interval of ketamine-induced LORR was 49.2 (43.4-56.4) mg/kg. About 4.0 or 8.0 mg/kg muscone increased ED50 of ketamine-induced hypnosis, which was 82.7 (70.0-98.4) mg/kg or 72.0 (65.4-85.7) mg/kg, respectively. In the analgesic experiment, ketamine alone caused an obvious analgesic effect, whereas different dose of muscone decreased pain threshold in the presence of ketamine; 4.0 mg/kg muscone up-regulated the mRNA expression of NR1 and inhibited ketamine-induced increase of δ-opioid receptor mRNA level. Muscone also inhibited Cav2.1 mRNA expression in the presence of ketamine.

CONCLUSION

Muscone reduced the hypnotic and analgesic effect of ketamine in dose-independent manner in mice, which may be related to the changes of NR1 and δ-opioid receptor.

Uwhangchungsimwon, A Standardized Herbal Drug, Exerts an Anti-Depressive Effect in a Social Isolation Stress-Induced Mouse Model

Introduction

Uwhangchungsimwon (UCW) is one of the most representative standardized herbal drugs for the treatment of central nervous system diseases, including mood disorders, and has been used for over 600 years in Korea and China. In spite of the long clinical application of UCW, no experimental evidence for its use against depressive disorders exists. Here, we performed an animal study to investigate the anti-depressive effect of UCW and the underlying mechanisms.

Methods

A social isolation-induced depressive-like model was produced using C57BL/6J male mice by housing the mice individually for 31 days, and the mice underwent daily oral administration of distilled water, UCW (100, 200, 400 mg/kg) or fluoxetine (20 mg/kg) during the final 17 days. A tail suspension test (TST), forced swimming test (FST), and open field test (OFT) were used to explore the effects of UCW on depressive-like behaviors. 5-Hydroxytryptamine (5-HT) was measured in the dorsal raphe nuclei (DRN) using immunofluorescence. The serum corticosterone level was measured with its receptor and catecholamine, along with cAMP response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) in the hippocampus.

Results

Social isolation stress effectively induced depressive-like behaviors, and UCW treatment significantly improved the symptoms of depressive-like behavior in the FST, TST, and OFT. The isolation stress-induced depletion of 5-HT was significantly ameliorated by UCW treatment. UCW also attenuated the activation of the glucocorticoid receptor (GR) and the elevated serum corticosterone level, as well as the hippocampal levels of dopamine and norepinephrine. Dexametasone-derived translocation of GR was inhibited by UCW treatment in PC12 cells and HT22 cells. In addition, alterations of tryptophan hydroxylase 2 (TPH2), BDNF, and CREB in the protein analyses were notably regulated by UCW treatment.

Conclusions

These results provide animal-based evidence for the anti-depressive effect of UCW, and its underlying mechanisms may involve regulating the serotonergic system, the hypothalamic-pituitary-adrenal (HPA) axis, and neurotrophin.

H2S attenuates injury after ischemic stroke by diminishing the assembly of CaMKII with ASK1-MKK3-p38 signaling module

Cerebral ischemia/reperfusion (I/R) injury is a leading cause of learning and memory dysfunction. Hydrogen sulfide (H₂S) has been shown to confer neuroprotection in various neurodegenerative diseases, including cerebral I/R-induced hippocampal CA1 injury. However, the underlying mechanisms have not been completely understood. In the present study, rats were pretreated with SAM/NaHS (SAM, an H₂S agonist, and NaHS, an H₂S donor) only or SAM/NaHS combined with CaM (an activator of CaMKII) prior to cerebral ischemia. The Morris water maze test demonstrated that SAM/NaHS could alleviate learning and memory impairment induced by cerebral I/R injury. Cresyl violet staining was used to show the survival of hippocampal CA1 pyramidal neurons. SAM/NaHS significantly increased the number of surviving cells, whereas CaM weakened the protection induced by SAM/NaHS. The immunohistochemistry results indicated that the number of Iba1-positive microglia significantly increased after cerebral I/R. Compared with the I/R group, the number of Iba1-positive microglia in the SAM/NaHS groups significantly decreased. Co-Immunoprecipitation and immunoblotting were conducted to demonstrate that SAM/NaHS suppressed the assembly of CaMKII with the ASK1-MKK3-p38 signal module after cerebral I/R, which decreased the phosphorylation of p38. In contrast, CaM significantly inhibited the effects of SAM/NaHS. Taken together, the results suggested that SAM/NaHS could suppress cerebral I/R injury by downregulating p38 phosphorylation via decreasing the assembly of CaMKII with the ASK1-MKK3-p38 signal module.

Betulinic acid derivatives can protect human Müller cells from glutamate-induced oxidative stress

Müller cells are the predominant retinal glial cells. One of the key roles of Müller cells is in the uptake of the neurotransmitter glutamate and in its conversion to glutamine. Müller cell dysfunction due to oxidative stress elicited by high glutamate concentrations can lead to toxicity, which promote the pathogenesis of retinal diseases like diabetic retinopathy and glaucoma. This study investigated the anti-oxidant activity and mechanisms of betulinic acid (BA) and its derivatives in human Müller cells. Human MIO-M1 Müller cells were pre-treated in the presence or absence of BA, BE as well as their derivatives (named H3-H20) followed by incubation with glutamate. Cell viability was evaluated with the MTT and calcein-AM assays. Reactive oxygen species (ROS) production in MIO-M1 cells was measured using CM-H₂DCFDA and flow cytometry. The activation of cellular apoptosis and necrosis was analyzed with annexin V/PI staining and flow cytometry. The modulation of signaling pathways involved in glutamate-mediated cytotoxicity and ROS production was evaluated by immunoblotting. The BA derivatives H3, H5 and H7 exhibited minimal cytotoxicity and significant anti-oxidant activity. These compounds significantly suppressed ROS production and attenuated cellular necrosis elicited by glutamate-induced oxidative stress. The protective effects of H3, H5 and H7 in MIO-M1 cells were associated with the attenuation of Akt, Erk, and JNK signaling. The BA analogues H3, H5 and H7 are protective against glutamate-induced oxidative stress in human Müller cells, and elicit their actions by modulation of the Erk, Akt and JNK signaling pathways. These agents are potential candidate molecules for the prevention or treatment of human retinal diseases.

Protective effect of Ketone musk on LPS/ATP-induced pyroptosis in J774A.1 cells through suppressing NLRP3/GSDMD pathway

Pyroptosis is a different type of proinflammatory and lytic mode of cell death from apoptosis and necrosis, which play a killer and cleaner to the pathogenic microorganisms as an immune response when the host is infected by pathogenic microorganisms. Ketone musk (KM) is a component of the native musk, which is widely used to medicine and chemical engineering. In this research, we studied whether KM can suppress the pyroptosis in J774A.1 cells induced by lipopoysaccharide (LPS)/Adenosine Triphosphate (ATP) stimulation. The results showed that KM increased the viability of LPS/ATP-stimulated cells, decreased the production of interleukin (IL)-1β/18, and suppressed the activation of caspased-1 and NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome and gasdermin D (GSDMD). Our present study demonstrated that KM inhibited LPS/ATP-induced pyroptosis and the release of IL-1β/18 in J774A.1 cells by inhibiting the activation of GSDMD and caspase-1 and the assembly of NLRP3 inflammasome. Our finding may be of significance on investigating that KM has a positive potential application in the treatment of pyroptosis-mediated diseases.

Attenuated glutamate induced ROS production by antioxidative compounds in neural cell lines

Glutamate is an excitatory neurotransmitter involved in neural function. Excess accumulation of intercellular glutamate leads to increasing concentration of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in neuronal cells. In this study, we investigated the antioxidant activity of several typical superior compounds among four neuronal cells, and determined the scavenging activity of free radicals. The in vivo assay was also carried out to compare the protective effect of glutamate-induced cell damage. Hierarchical clustering analysis was used to identify the common properties. Glutamate induced neurotoxicity and ROS production, suggesting glutamate cytotoxicity was related to oxidative stress and widely exists in different cell lines. Those screening compounds exhibited strong antioxidant ability, but low cytotoxicity to neuronal cells, acting as agents against neurodegenerative diseases. Finally, a hierarchical clustering analysis assay indicated that hyperoside and rutin hydrate are the most effective compounds for attenuating intercellular ROS levels. The results suggested the activity more or less relies on structure, rather than residues. These data generate new supporting ideas to remove intracellular ROS and the identified compounds serve as potential therapeutic agents in multiple neurological diseases.

Glutamate is an excitatory neurotransmitter involved in neural function.

Pien-Tze-Huang protects cerebral ischemic injury by inhibiting neuronal apoptosis in acute ischemic stroke rats

ETHNOPHARMACOLOGICAL RELEVANCE

Pien-Tze-Huang (PZH) is a famous formula of traditional Chinese medicine used to treating stroke. However, the protective effect of PZH and its mechanisms in acute ischemic stroke remain to be explored.

AIM OF THE STUDY

To investigate the protective effect of PZH on neuronal apoptosis in acute cerebral ischemic injury rats and explore its underlying mechanisms.

MATERIALS AND METHODS

The effects of PZH were studied in acute ischemic stroke rats induced by transient middle cerebral artery occlusion, and the mitochondria-mediated apoptotic proteins including cytochrome C (Cyt C), Bax, Bcl-xl, P53, caspase-3, and caspase-9 as well as AKT and glycogen synthase kinase-3 beta (GSK-3β) were assessed.

RESULTS

Four days of PZH treatment (180 mg/kg) could significantly reduce cerebral infarct volume, improve neurological deficit, attenuate inflammatory response, and inhibit neuronal apoptosis in acute ischemic stroke rats. Moreover, PZH treatment significantly decreased cytosolic Cyt C, Bax, P53, cleaved caspase-3, and cleaved caspase-9 levels, but elevated mitochondrial Cyt C and Bcl-xl levels. PZH treatment also increased phosphorylation of AKT and GSK-3β.

CONCLUSION

PZH potently protects the brain from cerebral ischemia/reperfusion injury in vivo, and inhibiting mitochondria-mediated neuronal apoptosis as well as attenuating inflammatory responses may be involved in this effect. This study provides experimental basis of PZH in treating acute cerebral ischemic stroke, which would provide some novel insights for its prevention and treatment of ischemic stroke.

UVB induces apoptosis via downregulation of CALML3-dependent JNK1/2 and ERK1/2 pathways in cataract

The aim of the current study was to understand the mechanisms of apoptosis occurring in cultured human lens epithelial cells (HLECs) following ultraviolet B (UVB) irradiation. The investigations intended to confirm the presence of apoptosis and to reveal the roles of oxidative stress, calcium (Ca2+), c‑Jun NH2‑terminal kinase (JNK)1/2, and extracellular signal‑regulated kinase (ERK)1/2 signaling pathway in these progresses. Cell apoptosis, ROS generation and intracellular Ca2+ concentration was measured by flow cytometry. The expression of CALML3, caspase-3, Bax, Bcl-2, p-JNK1/2, JNK1/2, p-ERK1/2 and ERK1/2 was measured by RT-qPCR and western blot analysis. Annexin V‑fluorescein isothiocyanate/propidium iodide staining demonstrated that UVB irradiation increased the apoptotic rate, reactive oxygen species (ROS) production and intracellular Ca2+ concentration of HLECs in dose‑ and time‑dependent manners. Overexpression of calmodulin like 3 (CALML3) reversed the effects of UVB irradiation on apoptosis, ROS production and Ca2+ concentration of HLECs, and decreased expressions of caspase‑3 and Bax, with increased expressions of Bcl‑2. Notably, silencing of CALML3 had similar effects to UVB irradiation and inhibited the activation JNK1/2 and ERK1/2 pathways. Nimodipine, a Ca2+‑channel antagonist, significantly attenuated the damages induced by CALML3 downregulation. In conclusion, UVB irradiation induced increase in apoptosis, ROS production and Ca2+ concentration of HLECs, in part, by downregulating the expression of CALML3 and involved oxidative stress, Ca2+, JNK1/2 and ERK1/2 signaling pathways, suggesting that investigating CALML3 may useful for developing cataract treatment.

MOK, a pharmacopuncture medicine, regulates thyroid dysfunction in L-thyroxin-induced hyperthyroidism in rats through the regulation of oxidation and the TRPV1 ion channel

Background

In this study, we evaluated the therapeutic effect of MOK, a pharmacopuncture medicine, on thyroid dysfunction in L-thyroxin (LT4)-induced hyperthyroidism rats.

Methods

The experimental hyperthyroidism model was prepared by the intraperitoneal injection of LT4 (0.5 mg/kg) once daily for 2 weeks in SD rats. MOK extract was injected at doses of 0.3 or 3 mg/kg on acupuncture points in the thyroid glands of LT4-induced hypothyroidism rats once a day for 2 weeks. The body temperature, body weight, and food/water intake were measured once a week for 2 weeks. The levels of thyroid hormones, total cholesterol, LDL-cholesterol, GOT, and GPT were measured in the sera of rats using ELISA and an automatic blood analyzer. The histological changes of thyroid tissues were observed by H&E staining. The expression of thermo-regulating protein, TRPV1 was determined by western blot in dorsal root ganglion (DRG) and brain tissues. We also measured the contents of GSH in the liver and antioxidant enzymes, SOD, and catalase in the liver, heart, and brain tissues by enzyme-based assay and Western blot, respectively.

Results

The acupuncture of MOK extract on the thyroid gland of LT4-induced hyperthyroidism rats significantly decreased the body temperature, and did not change body weight and food and water intakes. MOK acupuncture significantly increased the level of TSH, and decreased the levels of T3 and T4 in hyperthyroidism rats. The expression of TRPV1 was inhibited in both DRG and brain tissues after MOK acupuncture, and the levels of GOT, GPT, total cholesterol, and LDL-cholesterol were also decreased. MOK acupuncture also inhibited the pathological feature with follicular lining epithelial thicknesses and increased follicular colloid depositions in the thyroid glands of hypothyroidism. MOK acupuncture significantly increased hepatic GSH levels and decreased the expression of SOD and catalase in the liver, heart, and brain tissues of hyperthyroidism rats.

Conclusions

These results suggest that the pharmacopuncture with MOK extract in hyperthyroidism can improve the pathophysiological changes through regulating the body temperature, thyroid hormones imbalance, lipid accumulation, and oxidation. This anti-hyperthyroidism effect of MOK pharmacopuncture is thought to be related to the control of thermo-regulating protein TRPV1 in DRG and brain.

Muscone exerts protective roles on alcohol-induced osteonecrosis of the femoral head

Long-term alcohol abuse causes musculoskeletal disorders, among of which, alcohol-induced osteonecrosis of the femoral head (ONFH) is of concern due to its significant and severe complications. A variety of methods have been attempted to prevent alcohol-induced ONFH, and monomers extracted from Chinese herbs might benefit the disease profoundly. In the current study, muscone, the main ingredient of musk, was used to prevent alcohol-induced ONFH. In vitro, ethanol was used to affect the potential of osteogenesis and proliferation of human bone mesenchymal stem cells (hBMSCs), and beneficial role of muscone was investigated on hBMSCs. In vivo, following the establishment of alcohol-induced ONFH, muscone was employed to treat the diseased rats, which were analyzed by micro-CT scanning and a series of histologic staining. As a result, we found ethanol could significantly suppress osteogenic differentiation of hBMSCs, while muscone held the potential to promote ALP activity and mRNA expressions of COL1 and OCN under ethanol treatment. Meanwhile, imaging analysis revealed muscone could restore BV/TV ratio and bone mineral density of the necrotic femoral head, and the protective role of muscone on alcohol-induced ONFH was further confirmed by histologic examinations. Our study confirmed the protective effect of muscone against alcohol-induced ONFH both in vitro and in vivo. Therefore, muscone may be considered as a valuable therapeutic natural drug for alcohol-induced ONFH in humans.

Xingnaojing for Moderate-to-severe Acute ischemic Stroke (XMAS): study protocol for a randomized controlled trial

Background

Xingnaojing injection (XNJ) is widely used for the treatment of stroke in China. However, there is currently a lack of high-quality evidence of its efficacy for acute ischemic stroke. The main objective of this study is to determine whether the addition of XNJ to standard care improves the 3-month functional outcome in patients with acute ischemic stroke (AIS).

Methods/design

The XMAS study is a multicenter, prospective, randomized controlled, open-label trial with a blinded endpoints design. A total of 720 patients will be randomly allocated to either the intervention or the control group in a 1:1 ratio. The intervention group receives XNJ combined with standard care, and the control group receives standard care alone. XNJ will be administered intravenously every 12 h for 10 days. The primary outcome is the proportion of patients who are independent at 3 months after stroke onset defined as a modified Rankin Scale score of 0 to 2. Secondary outcomes include early neurological deterioration at 48 h, the change in National Institutes of Health Stroke Scale score, patient-reported outcome, symptomatic intracranial hemorrhage at 10 days, the Barthel Index score, deaths from any cause and cardiovascular events at 3 months.

Discussion

The results of this trial will provide critical evidence for XNJ in the treatment of AIS as a complementary approach that can be initiated after reperfusion therapy or when the AIS is not eligible for thrombolytic treatment.

Trial registration

Clinical Trials.gov, ID: NCT02728180. Registered on 28 March 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2222-y) contains supplementary material, which is available to authorized users.

GC-MS/MS method for the determination and pharmacokinetic analysis of borneol and muscone in rat after the intravenous administration of Xingnaojing injection

A simple and sensitive gas chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of borneol and muscone in rat plasma. The analytes and internal standard, naphthalene, were extracted using a convenient one-step liquid-liquid extraction method with ethyl acetate. The chromatographic separation was realized on a HP-5MS capillary column and detected in multiple reaction monitoring mode. Excellent linearity (R²  ≥ 0.996) was shown over 10.0-5000 ng/mL for borneol and 2.5-250 ng/mL for muscone. The lower limit of quantitation was 10 and 2.5 ng/mL for borneol and muscone, respectively. The intra- and interday precisions were less than 7.52%, and the accuracy values were between  -8.03 and 14.52%. The extraction recovery, matrix effect, and stability were sufficient to meet the Food and Drug Administration criteria. Meanwhile, the assay was successfully applied to the preclinical pharmacokinetic study of borneol and muscone following intravenous administration of Xingnaojing injection, a modern Chinese herbal medicine preparation.

Simultaneous quantification six active compounds in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study of Pien-Tze-Huang

Pien-Tze-Huang (PZH) is a popular traditional Chinese medicine (TCM) formula in China, but its pharmacokinetics has not been investigated yet. To better study the pharmacokinetic behaviors of PZH, an optimal ultra-performance liquid chromatography with triple quadrupole mass spectrometry (UPLC-MS/MS) method was developed for rapid quantification of six compounds (notoginsenoside R1, ginsenosides Re, Rg1, Rb1, Rd, and muscone) in rat plasma after oral administration of PZH. All analytes were extracted by protein precipitation with acetonitrile and separated on a Waters Acquity Cortecs C18 column within 3.9min, and detected by multiple-reaction monitoring in positive ion mode. This proposed method exhibited good linearity (r≥0.9932) with a lower quantification limits of 0.558-1.566ng/mL for all analytes. The intra- and inter-day precisions were within 8.24%, and the accuracy was within -10.05 to 9.87% for each analyte. The extraction recovery for each analyte ranged from 80.02 to 96.12%. This UPLC-MS/MS method was successfully applied to the pharmacokinetic study for PZH in rats.

Paeoniflorin exerts neuroprotective effects against glutamate‑induced PC12 cellular cytotoxicity by inhibiting apoptosis

Paeoniflorin (PF) is an active ingredient of Radix Paeoniae, which is known to exert neuroprotective effects. However, the mechanims behind the neuroprotective effects of PF are not yet fully understood. The apoptosis of neurons plays an important role in the cerebral ischemia-induced cascade response. This study aimed to investigate neuroprotective effects of PF against glutamate‑induced PC12 cellular cytotoxicity and to determine whether these effects are mediated via the inhibition of apoptosis in vitro and the activity of mitochondrial apoptosis-associated proteins in PC12 cells. Exposure of the PC12 cells to glutamate induced cell morphological changes, significantly decreased cell viability and induced apoptosis, with similar results being observed from the Hoechst 33342 staining and Annexin V/PI staining experiments. Glutamate also increased the lactate dehydrogenase release by the PC12 cells. However, treatment with PF prevented these effects. Furthermore, PF inhibited Bax and Bad expression and increased Bcl-2 and Bcl-xL expression; it also decreased the levels of downstream protein (caspase-3 and caspase-9). Collectively, our results indicate that PF protects PC12 cells against glutamate-induced neurotoxicity possibly through the inhibition of the expression of mitochondrial apoptosis-associated proteins.

Astaxanthin attenuates glutamate-induced apoptosis via inhibition of calcium influx and endoplasmic reticulum stress

Astaxanthin (AST) is a carotenoid that has been shown to have neuroprotective effects. In this study, it was found that AST significantly inhibited glutamate-induced loss of cell viability and apoptosis. AST pretreatment attenuated glutamate-induced activation of caspase-3, reduction of anti-apoptotic protein Bcl-2, and increase of pro-apoptotic protein Bak. In addition, AST pretreatment suppressed the production of intracellular reactive oxygen species. AST treatment also prevented glutamate-induced increase of the level of activated p38 mitogen-activated protein kinase (MAPK), which has been shown to promote apoptotic events. Furthermore, AST treatment greatly reduced the elevation of intracellular calcium level induced by glutamate and inhibited the activity of calpain, a calcium-dependent protease that plays an important role in mediating apoptosis stimulated by calcium overload in cytoplasm. Both oxidative stress and calcium overload can lead to endoplasmic reticulum (ER) stress. C/EBP-homologous protein (CHOP) is a bZIP transcription factor that can be activated by ER stress and promotes apoptosis. Here we found that AST attenuated glutamate-induced elevation of CHOP and ER chaperone glucose-regulated protein (GRP78). Overall, these results suggested that AST might protect cells against glutamate-induced apoptosis through maintaining redox balance and inhibiting glutamate-induced calcium influx and ER stress.

Effect of epigallocatechin-3-gallate on acrylamide-induced oxidative stress and apoptosis in PC12 cells

Acrylamide (ACR) is a chemical intermediate utilized in industry. ACR is also formed during heating of foods containing carbohydrates and amino acids. Therefore, humans are widely exposed to ACR, and ACR neurotoxicity in humans is a significant public health issue attracting wide attention. In this study, we investigated the potential neuroprotective effects of epigallocatechin-3-gallate (EGCG), the most abundant polyphenolic compound in green tea, in PC12 cells treated with ACR. ACR-treated PC12 cells pretreated with various concentrations of EGCG (2.5, 5 and 10 μM) for 24 h had increased viability and acetylcholinesterase activity and reduced apoptosis and necrosis compared to cells exposed to ACR alone. EGCG reduced the expression of bax mRNA, decreased cytochrome c release, reduced intracellular calcium levels, inactivated caspase 3 and increased mitochondrial membrane potential, suggesting that EGCG prevents ACR-induced apoptosis through a mitochondrial-mediated pathway. In addition, EGCG inhibited the formation of reactive oxygen species and lipid peroxidation while enhancing superoxide dismutase activity and glutathione levels, thereby reducing oxidative stress. Our results indicate that pretreatment of PC12 cells with EGCG attenuates ACR-induced apoptosis by reducing oxidative stress. Therefore, drinking green tea may reduce nerve injury induced by ACR.

Application of the Co-culture Membrane System Pointed to a Protective Role of Catestatin on Hippocampal Plus Hypothalamic Neurons Exposed to Oxygen and Glucose Deprivation

Depletion of oxygen and glucose even for brief periods is sufficient to cause cerebral ischemia, which is a predominant worldwide cause of motor deficits with the reduction of life quality and subsequently death. Hence, more insights regarding protective measures against ischemic events are becoming a major research goal. Among the many neuronal factors, N-methyl-D-aspartate receptors (NMDAR), orexinergic neuroreceptors (ORXR), and sympatho-inhibitory neuropeptide catestatin (CST) are widely involved with ischemic episodes. In this study, it was possible to induce in vitro ischemic conditions of the hamster (Mesocricetus auratus) hippocampal and hypothalamic neuronal cultures, grown on a newly compartmentalized membrane system, via oxygen and glucose deprivation (OGD). These cultures displayed notably differentiated NMDARergic and ORXergic receptor expression activities along with evident brain-derived neurotrophic factor (BDNF) plus orexin A (ORX-A) secretion, especially under co-cultured conditions. Interestingly, addition of CST in OGD-insulted hippocampal cells accounted for upregulated GluN1 and ORX1R transcripts that in the case of the latter neuroreceptor was very strongly (p < 0.001) increased when co-cultured with hypothalamic cells. Similarly, hypothalamic neurons supplied very evident upregulations of GluN1, ORX1R, and above all of GluN2A transcripts along with increased BDNF and ORX-A secretion in the presence of hippocampal cells. Overall, the preferential CST effects on BDNF plus ORX-A production together with altered NMDAR and ORXR levels, especially in co-cultured hypothalamic cells pointed to ORX-containing neurons as major protective constituents against ischemic damages thus opening new scenarios on the cross-talking roles of CST during ischemic disorders.

Alteration of glutamate/GABA balance during acute alcohol intoxication in rats: effect of Xingnaojing injection

ETHNOPHARMACOLOGICAL RELEVANCE

Xingnaojing Injection (XNJI) is a modern Chinese formula came from famous Chinese medicine An Gong Niu Huang Pill. XNJI has been used for treatment of cerebral diseases and stroke in China, and is approved by the State Food and Drug Administration of China for the treatment of acute alcohol intoxication (AAI). XNJI belongs to the ethnopharmacological family of medicines. In this study, we investigated the mechanisms of the XNJI effect on AAI.

AIM OF THE STUDY

To investigate the effects of XNJI on glutamate, gamma-aminobutyric acid (GABA) and related receptor in lateral hypothalamic area (LHA) of AAI rat.

MATERIAL AND METHODS

Adult male Sprague-Dawley rats were implanted with microdialysis probes in LHA. Rats were randomly divided into control, model, 1.36mg/kg XNJI, 0.68mg/kg XNJI and 0.34mg/kg XNJI groups. During microdialysis, baseline samples were collected from 1h to 2.5h; thereafter, the rats were given an intraperitoneal injection of 52% ethanol, 5.2g/kg, or saline for control group. Twenty minutes later, three doses of XNJI was given by unilateral injection respectively, while saline for control and model groups, and samples were collected for the next 4h. The extracellular glutamate and GABA levels were measured in the LHA by a high performance liquid chromatography coupled with fluorescence detector (HPLC-FLU). The expression levels of related receptors N-methyl-d-aspartate receptor (NR) subunit NR2A, NR2B and GABAA were analyzed by reverse transcription polymerase chain reaction (RT-PCR).

RESULTS

Ethanol (5.2g/kg) significantly decreased the extracellular levels of glutamate and increased extracellular GABA in LHA. On the other hand ethanol significantly decreased NR2A and NR2B mRNAs expression, and increase GABAA mRNA expression. XNJI could increase the extracellular level of glutamate and decrease that of GABA; moreover, induced an increase in NR2A and NR2B mRNA expression, and a decrease in GABAA mRNA expression in LHA.

CONCLUSIONS

The current changes in glutamate, GABA and mRNA expressions of related receptors in LHA after injection of XNJI suggest that changes in these neurotransmitters and receptors as a potential mechanism of action for AAI.

Ligustrazinyl amides: a novel class of ligustrazine-phenolic acid derivatives with neuroprotective effects

Background

Ligustrazine has potent effects of thrombolysis, neuroprotection and vascular protection, which were important for effectively protecting the nervous system. Previous study in our laboratory reported that ligustrazine-benzoic acid derivatives have been shown to exhibit beneficial effect against CoCl₂-induced neurotoxicity in differentiated PC12 cells. To further improve ligustrazine’s neuroprotection, we integrated the ligustrazine and phenolic acid fragments into one molecule via an amide bond based on structural combination.

Results

In this study, 12 novel ligustrazine-phenolic acid derivatives were synthesized and nine others were prepared by improved methods. Furthermore, these compounds were evaluated for their protective effects against CoCl₂-induced neurotoxicity in differentiated PC12 cells. The amides conjunctional derivatives exhibited promising neuroprotective activities in comparison with ligustrazine. In addition, the most active congener (E)-3-(2,3,4-trimethoxyphenyl)-N-((3,5,6-trimethylpyrazin-2-yl)methyl)acrylamide (L10, EC₅₀ = 25 μM), which is 2 times higher than that of ligustrazine, may be a potential candidate for intervention in neurological diseases. Structure-activity relationship was discussed briefly.

Conclusions

Results of series of ligustrazinyl amides enrich the study of ligustrazine derivatives with neuroprotective effects. Our completed work supports that the attempt to apply structure combination to discover more efficient neuroprotection lead compounds is viable.

Graphical Abstract

Resolution and chiral recognition of muscone as well as actions on neural system

In this letter, (R)-muscone and (S)-muscone were prepared by optical resolution of dl-muscone using N,N'-dibenzyl-l-tartaramide or N,N'-dibenzyl-d-tartaramide, according to the method reported by Kunihiko Takabe. But we separated the diastereomers using EtOH instead of MeOH in the recrystallization step to get the goal product with higher optical purity and yield. The regulatory effect of muscone and its enantiomer on the neural system showed that they could prolong mouse hypoxia tolerance and dose-dependently enhance mouse spinal cord stimulation induced by strychnine nitrate. (R)-muscone and (S)-muscone had a synergistic action on shortening sleep time induced by sodium pentobarbital in mice.