Tangeretin Mitigates Trimethylamine Oxide Induced Arterial Inflammation by Disrupting Choline-Trimethylamine Conversion through Specific Manipulation of Intestinal Microflora.

Previous studies have revealed the microbial metabolism of dietary choline in the gut, leading to its conversion into trimethylamine (TMA). Polymethoxyflavones (PMFs), exemplified by tangeretin, have shown efficacy in mitigating choline-induced cardiovascular inflammation. However, the specific mechanism by which these compounds exert their effects, particularly in modulating the gut microbiota, remains uncertain. This investigation focused on tangeretin, a representative PMFs, to explore its influence on the gut microbiota and the choline-TMA conversion process. Experimental results showed that tangeretin treatment significantly attenuated the population of CutC-active bacteria, particularly Clostridiaceae and Lactobacillus, induced by choline chloride in rat models. This inhibition led to a decreased efficiency in choline conversion to TMA, thereby ameliorating cardiovascular inflammation resulting from prolonged choline consumption. In conclusion, tangeretin's preventive effect against cardiovascular inflammation is intricately linked to its targeted modulation of TMA-producing bacterial activity.

Four undescribed coumarin derivatives, with ten amides from the roots of Ficus hirta and their cytotoxic activities.

Four undescribed coumarin derivatives, ficusalt A (1) and ficusalt B (2), a pair of racemic coumarins, (±) ficudimer A (3a/3b), along with ten known amides, were isolated from the roots of Ficus hirta. Their structures were elucidated by several spectroscopic data analyses, including HRESIMS, NMR, and X-ray single-crystal diffraction. The cytotoxic activities of all compounds against HeLa, HepG2, MCF-7, and H460 cell lines were detected using the MTT assay. Among these, 5 showed the highest activity against HeLa cells. Subsequently, the apoptotic, anti-invasive, and anti-migration effects of 5 on HeLa cells were determined by flow cytometer, transwell invasion assay, and wound-healing assay, respectively. The result suggested that 5 distinctly induced the apoptosis in HeLa cells and inhibited their invasion and migration. Further studies on anticancer mechanisms were conducted using Western blotting. As a result, 5 increased the cleavage of PARP and the expression of pro-apoptotic protein Bax. Moreover, 5 notably upregulated the phosphorylation of p38 and JNK, whereas inhibited the expression of p-ERK and p-AKT. Our results demonstrated that 5 could be a potential leading compound for further application in the treatment of cervical cancer.

Electroacupuncture at "Baihui, Yintang and Shuigou" Acupoints Improves Post-Stroke Cognitive Impairment in Mice.

OBJECTIVE: To study the effect and mechanism of electroacupuncture at "Baihui, Yintang and Shuigou" acupoints on learning and memory in Post-Stroke Cognitive Impairment (PSCI) mice. METHODS: 52 male C57BL/6 mice were used to establish a MACO model by using middle cerebral artery occlusion (n=38), while the Sham only ligated at the distal end of the external carotid artery (n=14). After 28 days, the MCAO was divided into three groups based on the escape latency of Morris water maze: non cognitive impairment (MNP), post-stroke cognitive impairment (MP), and electroacupuncture intervention group (MPEA). In the MPEA, electroacupuncture at "Baihui and Yintang" acupoints was performed for 20 minutes (density wave, 2/15HZ and 1mA) supplemented by acupuncture at "Shuigou" acupoints once a day with a 6-day course of treatment. The intervention last for 2 courses with a 1-day interval. Morris water maze was used to detect the cognitive function of mice in each group; Nissl staining was used to observe hippocampal neurons; Western blot was used to detect the expression of GluA1, Syp, and Syt-1 in the affected hippocampus; IHC was used to detect the expression of Syp in the CA1 region of the contralateral hippocampus. CONCLUSION: Acupuncture at points "Baihui, Yintang, and Shuigou" can improve the learning and memory abilities of PSCI mice, and its mechanism is related to synaptic plasticity of hippocampus.

Induction of Acute Ischemic Stroke in Mice Using the Distal Middle Artery Occlusion Technique.

Ischemic stroke remains the predominant cause of mortality and functional impairment among the adult populations globally. Only a minority of ischemic stroke patients are eligible to receive intravascular thrombolysis or mechanical thrombectomy therapy within the optimal time window. Among those stroke survivors, around two-thirds suffer neurological dysfunctions over an extended period. Establishing a stable and repeatable experimental ischemic stroke model is extremely significant for further investigating the pathophysiological mechanisms and developing effective therapeutic strategies for ischemic stroke. The middle cerebral artery (MCA) represents the predominant location of ischemic stroke in humans, with the MCA occlusion serving as the frequently employed model of focal cerebral ischemia. In this protocol, we describe the methodology of establishing the distal MCA occlusion (dMCAO) model through transcranial electrocoagulation in C57BL/6 mice. Since the occlusion site is located at the cortical branch of MCA, this model generates a moderate infarcted lesion restricted to the cortex. Neurological behavioral and histopathological characterization have demonstrated visible motor dysfunction, neuron degeneration, and pronounced activation of microglia and astrocytes in this model. Thus, this dMCAO mouse model provides a valuable tool for investigating the ischemiastroke and worth of popularization.

Chebulic Acid Prevents Hypoxia Insult via Nrf2/ARE Pathway in Ischemic Stroke.

Excessive reactive oxygen species (ROS) production contributes to brain ischemia/reperfusion (I/R) injury through many mechanisms including inflammation, apoptosis, and cellular necrosis. Chebulic acid (CA) isolated from Terminalia chebula has been found to have various biological effects, such as antioxidants. In this study, we investigated the mechanism of the anti-hypoxic neuroprotective effect of CA in vitro and in vivo. The results showed that CA could protect against oxygen-glucose deprivation/reoxygenation (OGD/R) induced neurotoxicity in SH-SY5Y cells, as evidenced by the enhancement of cell viability and improvement of total superoxide dismutase (T-SOD) in SH-SY5Y cells. CA also attenuated OGD/R-induced elevations of malondialdehyde (MDA) and ROS in SH-SY5Y cells. Nuclear factor-E2-related factor 2 (Nrf2) is one of the key regulators of endogenous antioxidant defense. CA acted as antioxidants indirectly by upregulating antioxidant-responsive-element (ARE) and Nrf2 nuclear translocation to relieve OGD/R-induced oxidative damage. Furthermore, the results showed that CA treatment resulted in a significant decrease in ischemic infarct volume and improved performance in the motor ability of mice 24 h after stroke. This study provides a new niche targeting drug to oppose ischemic stroke and reveals the promising potential of CA for the control of ischemic stroke in humans.

Neuroprotective Effect of Polyphenol Extracts from Terminalia chebula Retz. against Cerebral Ischemia-Reperfusion Injury.

Current therapies for ischemic stroke are insufficient due to the lack of specific drugs. This study aimed to investigate the protective activity of polyphenol extracts from Terminalia chebula against cerebral ischemia-reperfusion induced damage. Polyphenols of ethyl acetate and n-butanol fractions were extracted from T. chebula. BV2 microglial cells exposed to oxygen-glucose deprivation/reoxygenation and mice subjected to middle cerebral artery occlusion/reperfusion were treated by TPE and TPB. Cell viability, cell morphology, apoptosis, mitochondrial membrane potential, enzyme activity and signaling pathway related to oxidative stress were observed. We found that TPE and TPB showed strong antioxidant activity in vitro. The protective effects of TPE and TPB on cerebral ischemia-reperfusion injury were demonstrated by enhanced antioxidant enzyme activities, elevated level of the nucleus transportation of nuclear factor erythroid 2-related factor 2 and expressions of antioxidant proteins, with a simultaneous reduction in cell apoptosis and reactive oxygen species level. In conclusion, TPE and TPB exert neuroprotective effects by stimulating the Nrf2 signaling pathway, thereby inhibiting apoptosis.

Retrograde Labeling of Different Distribution Features of DRG P2X2 and P2X3 Receptors in a Neuropathic Pain Rat Model.

The distributions of P2X subtypes during peripheral neuropathic pain conditions and their differential roles are not fully understood. To explore these characteristics, the lumbosacral dorsal root ganglion (DRG) in the chronic constriction injury (CCI) sciatic nerve rat model was studied. Retrograde trace labeling combined with immunofluorescence technology was applied to analyze the distribution of neuropathic nociceptive P2X1-6 receptors. Our results suggest that Fluoro-Gold (FG) retrograde trace labeling is an efficient method for studying lumbosacral DRG neurons in the CCI rat model, especially when the DRG neurons are divided into small, medium, and large subgroups. We found that neuropathic nociceptive lumbosacral DRG neurons (i.e., FG-positive cells) were significantly increased in medium DRG neurons, while they declined in the large DRG neurons in the CCI group. P2X3 receptors were markedly upregulated in medium while P2X2 receptors were significantly decreased in small FG-positive DRG neurons. There were no significant changes in other P2X receptors (including P2X1, P2X4, P2X5, and P2X6). We anticipate that P2X receptors modulate nociceptive sensitivity primarily through P2X3 subtypes that are upregulated in medium neuropathic nociceptive DRG neurons and/or via the downregulation of P2X2 cells in neuropathic nociceptive small DRG neurons.

Alteration of P2X1-6 receptor expression in retrograde Fluorogold-labeled DRG neurons from rat chronic neuropathic pain model.

Accumulating evidence indicates that P2X receptors may serve an important role in pain and nociceptive sensations. However, recent studies of regulation of P2X receptor expression following nerve injury have produced variable or conflicting results. In the present study the alteration of expression of P2X1-6 receptor subunits in retrograde Flurorogold (FG)-labeled L4+L5 dorsal root ganglion (DRG) neurons were evaluated following unilateral chronic constriction injury (CCI) of the rat sciatic nerve using immunohistochemistry combined with a retrograde fluorescence-tracing method. It was demonstrated that there was no significant difference in the proportion of FG-labeled DRG neurons between the sham and CCI groups (P>0.5). The percentages of P2X1-immunoreactive (IR) and P2X2-IR FG-labeled DRG neurons were not significantly different between the sham and CCI groups (41.5±8.2 vs. 45.2±7.4% and 58.1±6.2 vs. 69.1±3.5%, P>0.05). The percentages of P2X3-IR and P2X6-IR FG-labeled DRG neurons significantly increased in the CCI group compared with the sham group (51.6±4.1 vs. 28.5±3.4% and 41.8±2.2 vs. 22.6±3.3%, P>0.01). By contrast, the percentage of P2X4-IR FG-labeled DRG neurons significantly decreased in the CCI group compared with the sham group (29.4±3.3 vs. 45.0±3.7%, P<0.01). The P2X5-IR positive FG-labeled neurons were not detected in the CCI and sham groups. The results of the present study provided the first evidence regarding the regulation of the expression of the P2X1-6 receptor in sensory neurons being directly associated with chronic nerve injury in rats and also suggest that compared with the P2X3 receptor, the P2X2/3 heteromeric receptor is not the major receptor involved in peripheral neuropathic pain sensation. In addition, the possible functional role of P2X6 receptors in peripheral neuropathic pain requires further investigation.

2 Hz EA Reduces Heroin Withdrawal-Induced Hyperalgesia and Heroin Relapse by Downregulating P2X3 Receptors in DRG Neurons.

Electroacupuncture (EA) has effective analgesic effects. Our previous study demonstrated that the upregulation of P2X3 receptors in the dorsal root ganglia (DRG) might participate in heroin withdrawal-induced hyperalgesia. The aim of this study is to further explore whether 2 Hz EA reduces heroin relapse associated with its analgesic effect and whether P2X3 receptors in the DRG are involved in this process. 2 Hz EA was adopted to treat the heroin SA rats in the present study. Heroin-seeking and pain sensitivity were evaluated. The expression of P2X3 receptors in the DRG was detected. Our results showed that compared with the control group, the reinstatement, thermal hyperalgesia, and mechanical allodynia of the heroin-addicted group were increased significantly. The expression of P2X3 receptors in the DRG was increased markedly. After being treated using 2 Hz EA, reinstatement was reduced, hyperalgesia was decreased, and the upregulated expression of P2X3 receptors in the DRG had decreased significantly compared to that in the heroin-addicted group. Consequently, our results indicated that 2 Hz EA was an effective method for treating heroin-induced hyperalgesia and helping prevent relapse, and the potential mechanism might be related to the downregulation of P2X3 receptor expression in the DRG.

Upregulation of P2X2 and P2X3 receptors in rats with hyperalgesia induced by heroin withdrawal.

Drug dependence and withdrawal syndrome induced by abrupt cessation of opioid administration remain a severe obstacle in the clinical treatment of chronic pain and opioid drug addiction. One of the key symptoms during opioid withdrawal is hyperalgesia. The mechanism of opioid withdrawal-induced hyperalgesia remains unclear. P2X2 and P2X3 receptors, members of P2X receptor subunits, act as the integrator of multiple forms of noxious stimuli and play an important role in nociception transduction of chronic neuropathic and inflammatory pain. The process of P2X2 and P2X3 receptor antagonism inhibits inflammatory hyperalgesia, involving the spinal opioid system. However, the role of P2X receptors involved in opioid withdrawal-induced hyperalgesia has seldom been discussed. To explore the role of P2X2 and P2X3 receptors in the opioid-induced hyperalgesia, heroin self-administration rats were adopted, and the thermal and mechanical nociceptive thresholds were evaluated using the paw withdrawal test after abstinence from heroin for 8 days. In addition, the expressions of P2X2 and P2X3 receptors in dorsal root ganglia were analyzed by immunofluorescence. The results showed that after 8 days of abstinence, heroin self-administration rats showed thermal hyperalgesia and mechanical allodynia. Meanwhile, the expressions of the P2X2 and P2X3 receptors in dorsal root ganglia were increased. These results suggest that upregulation of P2X2 and P2X3 receptors might partially play a role in heroin withdrawal-induced hyperalgesia.

Metabolomics analysis of serum in a rat heroin self-administration model undergoing reinforcement based on 1H-nuclear magnetic resonance spectra.

BACKGROUND: Understanding the process of relapse to abused drugs and ultimately developing treatments that can reduce the incidence of relapse remains the primary goal for the study of substance dependence. Therefore, exploring the metabolite characteristics during the relapse stage is valuable. METHODS: A heroin self-administered rat model was employed, and analysis of the 1H-nuclear magnetic resonance-based metabolomics was performed to investigate the characteristic metabolite profile upon reintroduction to the drug after abstinence. RESULTS: Sixteen metabolites in the serum of rats, including phospholipids, intermediates in TCA (Tricarboxylic Acid Cycle) cycle, keto bodies, and precursors for neurotransmitters, underwent a significant change in the reinstatement stage compared with those in the control group. In particular, energy production was greatly disturbed as evidenced by different aspects such as an increase in glucose and decrease in intermediates of glycolysis and the TCA cycle. The finding that the level of 3-hydroxybutyrate and acetoacetate increased significantly suggested that energy production was activated from fatty acids. The concentration of phenylalanine, glutamine, and choline, the precursors of major neurotransmitters, increased during the reinstatement stage which indicated that an alteration in neurotransmitters in the brain might occur along with the disturbance in substrate supply in the circulatory system. CONCLUSIONS: Heroin reinforcement resulted in impaired energy production via different pathways, including glycolysis, the TCA cycle, keto body metabolism, etc. A disturbance in the substrate supply in the circulatory system may partly explain heroin toxicity in the central nervous system. These findings provide new insight into the mechanism underlying the relapse to heroin use.

Mouse hepatic neoplasm formation induced by trace level and low frequency exposure to diethylnitrosamine through ß-catenin signaling pathway.

It has been reported that massive levels or/and high frequency exposure of diethylnitrosamine could induce hepatic neoplasm. However, it would be more interesting to figure out the hepatotoxic effects of diethylnitrosamine exposure at trace level and low frequency, which could be more common in our daily life. We found that both the mRNA and protein expression levels of ß-catenin were aberrant in all liver tissues, accompanied by inflammation, steatosis, fibrosis and hepatic neoplasm after 10-week exposure of diethylnitrosamine (dissolved in sesame oil, 0.16 mmol per kg body weight) to mice. In addition, gradual increase in the mRNA expression of several pivotal risk factors (TNF-α, COX-2, PPAR-γ, AP-2, Smad-2, TGF-ß1, and C-myc), as well as their protein expression levels, were associated with the aberrant expression or/and nucleus localization of ß-catenin. Altogether, our results show that long-term diethylnitrosamine exposure at trace amounts and low frequency can also induce hepatotoxicity (including inflammation, steatosis and fibrosis) and consequently aberrant activation of ß-catenin which in turn plays an important role in the initiation and promotion of liver tumors.

Up-Regulation of the Biosynthesis and Release of Substance P through Wnt/ß-Catenin Signaling Pathway in Rat Dorsal Root Ganglion Cells.

To examine regulatory effects of ß-catenin on the biosynthesis and release of substance P, a rat chronic constriction injury (CCI) model and a rat dorsal root ganglion (DRG) cell culture model were used in the present study. The CCI treatment significantly induced the overall expression of ß-catenin (158 ± 6% of sham) in the ipsilateral L5 DRGs in comparison with the sham group (109 ± 4% of sham). The CCI-induced aberrant expression of ß-catenin was significantly attenuated by oral administration of diclofenac (119 ± 6% of the sham value; 10 mg/kg). Importantly, aberrant nuclear accumulation of ß-catenin in cultured DRG cells resulted in up-regulation of the PPT-A mRNA expression and the substance P release. The up-regulation of both the PPT-A mRNA expression and the substance P release by either a GSK-3ß inhibitor TWS119 (10 µM) or a Wnt signaling agonist Wnt-3a (100 ng/ml) were significantly abolished by an inhibitor of cyclooxygenase-2 (COX-2; NS-398, 1 µM). Collectively, these data suggest that nociceptive input-activated ß-catenin signaling plays an important role in regulating the biosynthesis and release of substance P, which may contribute to the inflammation responses related to chronic pain.

Design of a polymer ligand for the one-step preparation of highly stable fluorescent Ag5 clusters for tissue labeling.

Highly stable water-soluble fluorescent Ag5 clusters with a quantum yield of 9.7% were synthesized using a specially designed tridentate polymer ligand by one-step reduction. The fluorescence may be associated with the dominant Ag+ species on the surface of the clusters. The resultant Ag nanoclusters were used as biomarkers to label mouse liver tissues successfully for the first time.