Chrysin ameliorates cerebral ischemia/reperfusion (I/R) injury in rats by regulating the PI3K/Akt/mTOR pathway

Synergistic effect of chrysin and kaempferol in ameliorating Cerebral Ischemic Reperfusion injury in rat by controlling expression of proinflammatory mediators NF-κB and STAT3

OBJECTIVES

The two flavonoids kaempferol and chrysin are known to possess anti-inflammatory and antioxidant activities. In addition, these two flavonoids were reported to display synergistic effects against inflammation. The present study aims to provide an analysis of the combined effects of kaempferol and chrysin on ischemic rat brain induced by endothelin-1.

METHODS

The neurological deficit score and infarct area of the brain were determined post drug treatment. Histopathological sections displayed the morphological changes in the brain tissue. The brain tissues were processed for assessing the antioxidant and anti-inflammatory activity by measuring superoxide dismutase activity, catalase activity, level of reduced glutathione, brain malondialdehyde, and amount of calcium. The expression level of inflammatory molecules was analyzed by western blotting and immunohistochemistry.

RESULTS

The infarct area, neurological score and NF-κB and STAT3 expression levels were significantly reduced.

DISCUSSION

The analysis of neuroprotective synergistic activity of kaempferol and chrysin indicated the therapeutic potential of the combination in alleviating cerebral ischemia by controlling expression of proinflammatory mediators.

Novel insight into the therapeutical potential of flavonoids from traditional Chinese medicine against cerebral ischemia/reperfusion injury

Cerebral ischemia/reperfusion injury (CIRI) is a major contributor to poor prognosis of ischemic stroke. Flavonoids are a broad family of plant polyphenols which are abundant in traditional Chinese medicine (TCM) and have beneficial effects on several diseases including ischemic stroke. Accumulating studies have indicated that flavonoids derived from herbal TCM are effective in alleviating CIRI after ischemic stroke in vitro or in vivo, and exhibit favourable therapeutical potential. Herein, we systematically review the classification, metabolic absorption, neuroprotective efficacy, and mechanisms of TCM flavonoids against CIRI. The literature suggest that flavonoids exert potential medicinal functions including suppressing excitotoxicity, Ca2+ overloading, oxidative stress, inflammation, thrombin's cellular toxicity, different types of programmed cell deaths, and protecting the blood-brain barrier, as well as promoting neurogenesis in the recovery stage following ischemic stroke. Furthermore, we identified certain matters that should be taken into account in future research, as well as proposed difficulties and opportunities in transforming TCM-derived flavonoids into medications or functional foods for the treatment or prevention of CIRI. Overall, in this review we aim to provide novel ideas for the identification of new prospective medication candidates for the therapeutic strategy against ischemic stroke.

Advances of phytotherapy in ischemic stroke targeting PI3K/Akt signaling

The pathogenesis of ischemic stroke is complex, and PI3K/Akt signaling is considered to play a crucial role in it. The PI3K/Akt pathway regulates inflammation, oxidative stress, apoptosis, autophagy, and vascular endothelial homeostasis after cerebral ischemia; therefore, drug research targeting the PI3K/Akt pathway has become the focus of scientists. In this review, we analyzed the research reports of antiischemic stroke drugs targeting the PI3K/Akt pathway in the past two decades. Because of the rich sources of natural products, increasing studies have explored the value of natural compounds, including Flavonoids, Quinones, Alkaloids, Phenylpropanoids, Phenols, Saponins, and Terpenoids, in alleviating neurological impairment and achieved satisfactory results. Herbal extracts and medicinal formulas have been applied in the treatment of ischemic stroke for thousands of years in East Asian countries. These precious clinical experiences provide a new avenue for research of antiischemic stroke drugs. Finally, we summarize and discuss the characteristics and shortcomings of the current research and put forward prospects for further in-depth exploration.

Chrysin restores the cardioprotective effect of ischemic preconditioning in diabetes-challenged rat heart

Background

Ischemic preconditioning (IPC) is the utmost capable design to achieve protection over ischemia-reperfusion injury (I/R), but this phenomenon gets attenuated during various pathological conditions like diabetes. Chrysin exhibits cardioprotection in various experiments however, its therapeutic potential on IPC-mediated cardioprotection via PI3K-Akt-eNOS pathway in streptozotocin (STZ) triggered diabetes-challenged rat heart is yet to be assessed. For that reason, the experiment has been planned to investigate chrysin's effect on the cardioprotective action of IPC involving the PI3K-Akt-eNOS cascade in rat hearts challenged to diabetes.

Methods

The project was accomplished through means of absorbance studies for biochemical parameters, infarct size measurement (TTC stain) and coronary flow.

Results

The findings of the present study revealed that STZ drastically augmented the serum glucose level and the chrysin significantly reversed the IPC-stimulated increased coronary flow, nitrite release, and reduced LDH (lactate dehydrogenase), CK-MB (creatine kinase) activities as well as infarct size in diabetes-induced rat heart. Furthermore, chrysin also reversed the IPC-induced reduction in oxidative stress in an isolated Langendorff's perfused diabetic rat heart. Moreover, four episodes of preconditioning by either PI3K or eNOS inhibitor in chrysin-pretreated diabetic rat hearts significantly abolished the protective effect of chrysin.

Conclusion

Consequently, these observations suggested that chrysin increases the therapeutic efficiency of IPC in mitigating I/R injury via PI3K-Akt-eNOS signalling in diabetes-challenged rat hearts. Hence, chrysin could be a potential alternative option to IPC in diabetic rat hearts.

Possible mechanisms involved in the neuroprotective effects of chrysin against mild traumatic brain injury-induced spatial cognitive decline: An in vivo study in a rat model

Traumatic brain injury (TBI) is recognized as an important risk factor for cognitive deficits. The present study was designed to determine the potential neuroprotective effects of chrysin, a natural flavonoid compound, against TBI-induced spatial cognitive decline and the possible mechanisms involved. Oral administration of chrysin (25, 50, or 100 mg/kg/day) was initiated in rats immediately following the induction of the diffuse TBI model using the weight-dropping Marmarou model. Spatial cognitive ability, hippocampal synaptic plasticity, blood-brain barrier (BBB) permeability, brain water content, and histological changes were assessed at scheduled time points. The animals subjected to TBI exhibited spatial cognitive decline in the Morris water maze (MWM) test, which was accompanied by inhibition of hippocampal long-term potentiation (LTP) induction at the perforant path-dentate gyrus (PP-DG) synapses. Additionally, TBI caused BBB disruption, brain edema, and neuronal loss. Interestingly, treatment with chrysin (especially in the dose of 100 mg/kg) alleviated all the above-mentioned neuropathological changes related to TBI. The results provide evidence that chrysin improves TBI-induced spatial cognitive decline, which may be partly related to the amelioration of hippocampal synaptic dysfunction, alleviation of BBB disruption, reduction of brain edema, and prevention of neuronal loss.

Schisandrin B Protects against Ischemic Brain Damage by Regulating PI3K/AKT Signaling in Rats

OBJECTIVE

To explore the effect and mechanism of schisandrin B (Sch B) in the treatment of cerebral ischemia in rats.

METHODS

The cerebral ischemia models were induced by middle cerebral artery occlusion (MCAO) and reperfusion. Sprague-Dawley rats were divided into 6 groups using a random number table, including sham, MCAO, MCAO+Sch B (50 mg/kg), MCAO+Sch B (100 mg/kg), MCAO+Sch B (100 mg/kg)+LY294002, and MCAO+Sch B (100 mg/kg)+wortmannin groups. The effects of Sch B on pathological indicators, including neurological deficit scores, cerebral infarct volume, and brain edema, were subsequently studied. Tissue apoptosis was identified by terminal transferase-mediated dUTP nick end-labeling (TUNEL) staining. The protein expressions involved in apoptosis, inflammation response and oxidative stress were examined by immunofluorescent staining, biochemical analysis and Western blot analysis, respectively. The effect of Sch B on phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling was also explored.

RESULTS

Sch B treatment decreased neurological deficit scores, cerebral water content, and infarct volume in MCAO rats (P<0.05 or P<0.01). Neuronal nuclei and TUNEL staining indicated that Sch B also reduced apoptosis in brain tissues, as well as the Bax/Bcl-2 ratio and caspase-3 expression (P<0.01). Sch B regulated the production of myeloperoxidase, malondialdehyde, nitric oxide and superoxide dismutase, as well as the release of cytokine interleukin (IL)-1 β and IL-18, in MCAO rats (P<0.05 or P<0.01). Sch B promoted the phosphorylation of PI3K and AKT. Blocking the PI3K/AKT signaling pathway with LY294002 or wortmannin reduced the protective effect of Sch B against cerebral ischemia (P<0.05 or P<0.01).

CONCLUSIONS

Sch B reduced apoptosis, inflammatory response, and oxidative stress of MCAO rats by modulating the PI3K/AKT pathway. Sch B had a potential for treating cerebral ischemia.

Neuronal Responses to Ischemia: Scoping Review of Insights from Human-Derived In Vitro Models

Translation of neuroprotective treatment effects from experimental animal models to patients with cerebral ischemia has been challenging. Since pathophysiological processes may vary across species, an experimental model to clarify human-specific neuronal pathomechanisms may help. We conducted a scoping review of the literature on human neuronal in vitro models that have been used to study neuronal responses to ischemia or hypoxia, the parts of the pathophysiological cascade that have been investigated in those models, and evidence on effects of interventions. We included 147 studies on four different human neuronal models. The majority of the studies (132/147) was conducted in SH-SY5Y cells, which is a cancerous cell line derived from a single neuroblastoma patient. Of these, 119/132 used undifferentiated SH-SY5Y cells, that lack many neuronal characteristics. Two studies used healthy human induced pluripotent stem cell derived neuronal networks. Most studies used microscopic measures and established hypoxia induced cell death, oxidative stress, or inflammation. Only one study investigated the effect of hypoxia on neuronal network functionality using micro-electrode arrays. Treatment targets included oxidative stress, inflammation, cell death, and neuronal network stimulation. We discuss (dis)advantages of the various model systems and propose future perspectives for research into human neuronal responses to ischemia or hypoxia.

Chrysin loaded nanovesicles ameliorated diabetic peripheral neuropathy. Role of NGF/AKT/GSK-3β pathway

Diabetic peripheral neuropathy (DPN) is a common diabetic complication. Chrysin (CHY) has many biological properties but poor oral bioavailability. This study investigates the effect of CHY and CHY-loaded nanovesicles (CHY-NVs) on streptozotocin (STZ)-induced DPN in rats. CHY-NVs were prepared by using film hydration method. The formula with the best entrapment efficiency%, lowest particle size, highest zeta potential, and highest in vitro CHY released profile was selected, characterized by Differential scanning calorimetry, Fourier transformation infrared spectroscopy analysis, and examined by Transmission electron microscope. Acute toxicity test, pharmacokinetic study and experimental model of diabetes mellitus were performed on the selected formulation. Wistar rats were considered diabetic by administration of a single intraperitoneal dose of STZ (50 mg/kg). 48 h after STZ administration, hyperglycemic rats were randomly assigned into four groups, one group of untreated hyperglycemic rats and the other three groups received daily oral doses of unloaded NVs, CHY-NVs (25 mg/kg), and CHY-NVs (50 mg/kg), respectively for 21 days. Moreover, five additional groups of healthy rats received: distilled water (control), free CHY, unloaded NVs, and CHY-NVs respectively for 21 days. CHY and CHY-NVs maintained body weight and reduced STZ-induced behavioral changes in rotarod, hind paw cold allodynia, tail cold allodynia, tail flick, and hot plate tests. CHY and CHY-NVs lowered blood glucose, glycated hemoglobin, elevated serum reduced glutathione (GSH), and reduced plasma malondialdehyde (MDA) levels. CHY-NVs elevated phosphatidylinositol 3-kinase (Pi3k), phosphorylated protein kinase B (p-AKT), and reduced nuclear factor kappa B (NF-κB), interleukin-6 (IL-6) in sciatic nerve homogenate. CHY and CHY-NVs increased nerve growth factor (NGF) and decreased glycogen synthase kinase-3β (GSK-3β) gene expressions in the sciatic nerve. In conclusion, CHY and CHY-NVs ameliorated STZ-induced DPN behavioral and histopathological changes via attenuating hyperglycemia, exerting anti-oxidant, anti-inflammatory effects, activating NGF/p-AKT/GSK-3β pathway, and its anti-apoptotic effect. The best pharmacokinetic profile and therapeutic effect was observed in rats treated with CHY-loaded NVs.

Chrysin protects against cerebral ischemia-reperfusion injury in hippocampus via restraining oxidative stress and transition elements

Chrysin is a natural flavonoid compound that has antioxidant and neuroprotective effects. Cerebral ischemia reperfusion (CIR) is closely connected with increased oxidative stress in the hippocampal CA1 region and homeostasis disorder of transition elements such as iron (Fe), copper (Cu) and zinc (Zn). This exploration was conducted to elucidate the antioxidant and neuroprotective effects of chrysin based on transient middle cerebral artery occlusion (tMCAO) in rats. Experimentally, sham group, model group, chrysin (50.0 mg/kg) group, Ginaton (21.6 mg/kg) group, Dimethyloxallyl Glycine (DMOG, 20.0 mg/kg) + chrysin group and DMOG group were devised. The rats in each group were performed to behavioral evaluation, histological staining, biochemical kit detection, and molecular biological detection. The results indicated that chrysin restrained oxidative stress and the rise of transition element levels, and regulated transition element transporter levels in tMCAO rats. DMOG activated hypoxia-inducible factor-1 subunit alpha (HIF-1α), reversed the antioxidant and neuroprotective effects of chrysin, and increased transition element levels. In a word, our findings emphasize that chrysin plays a critical role in protecting CIR injury via inhibiting HIF-1α against enhancive oxidative stress and raised transition metal levels.

Anti-Inflammatory Effects of Flavonoids in Common Neurological Disorders Associated with Aging

Aging reduces homeostasis and contributes to increasing the risk of brain diseases and death. Some of the principal characteristics are chronic and low-grade inflammation, a general increase in the secretion of proinflammatory cytokines, and inflammatory markers. Aging-related diseases include focal ischemic stroke and neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Flavonoids are the most common class of polyphenols and are abundantly found in plant-based foods and beverages. A small group of individual flavonoid molecules (e.g., quercetin, epigallocatechin-3-gallate, and myricetin) has been used to explore the anti-inflammatory effect in vitro studies and in animal models of focal ischemic stroke and AD and PD, and the results show that these molecules reduce the activated neuroglia and several proinflammatory cytokines, and also, inactivate inflammation and inflammasome-related transcription factors. However, the evidence from human studies has been limited. In this review article, we highlight the evidence that individual natural molecules can modulate neuroinflammation in diverse studies from in vitro to animal models to clinical studies of focal ischemic stroke and AD and PD, and we discuss future areas of research that can help researchers to develop new therapeutic agents.

Possible mechanisms involved in the protective effects of chrysin against lead-induced cognitive decline: An in vivo study in a rat model

Lead (Pb) is a highly poisonous environmental pollutant that can induce cognitive decline. Chrysin, a natural flavonoid compound, has anti-oxidative, anti-inflammatory, and neuroprotective properties in different neurodegenerative disorders. The present study was designed to examine the putative effects of chrysin against Pb-induced cognitive impairment and the possible involved mechanisms. Adult male Wistar rats were exposed to Pb acetate (500 ppm in standard drinking water) either alone or in combination with daily oral administration of chrysin (30 mg/kg) for eight consecutive weeks. During the eight-week period of the study, the cognitive capacity of the rats was evaluated by employing both novel object recognition and passive avoidance tests. On day 56, hippocampal synaptic plasticity (long-term potentiation; LTP) was recorded in perforant path-dentate gyrus (PP-DG) synapses to assess field excitatory postsynaptic potentials (fEPSPs) slope and population spike (PS) amplitude. Subsequently, pro- and anti-inflammatory cytokines and histological changes were evaluated in the cerebral cortex and hippocampus of the rats. Moreover, Pb levels in blood and brain tissues were assessed. The results showed that Pb exposure causes cognitive decline, inhibition of hippocampal LTP induction, imbalance of pro- and anti-inflammatory cytokines, enhancement of Pb levels in blood and brain tissues, and neuronal loss. However, chrysin treatment improved cognitive dysfunction, ameliorated hippocampal LTP impairment, modulated inflammatory status, reduced Pb concentration, and prevented neuronal loss in the Pb-exposed rats. The results suggest that chrysin alleviates Pb-induced cognitive deficit, possibly through mitigation of hippocampal synaptic dysfunction, modulation of inflammatory status, reduction of Pb concentration, and prevention of neuronal loss.

Exploring the potential anti-Alzheimer disease mechanisms of Alpiniae Oxyphyliae Fructus by network pharmacology study and molecular docking

Alpiniae Oxyphyliae Fructus (AOF) (yizhi) is a frequently medicated Chinese herb for Alzheimer disease (AD) treatment. The present study investigated the components and potential mechanisms of AOF through network pharmacology analysis and molecular docking. The results showed that AOF contains at least 20 active ingredients and involves 184 target genes. A total of 301 AD-related genes were obtained from the DisGeNET, GeneCards, GEO, OMIM, and Alzheimer Disease: Genes databases. A total of 41 key targets were identified from the topology analysis of the AOF-AD target network. These key targets are involved in 105 signal pathways, such as the PI3K-Akt, HIF-1, and MAPK pathways, and can regulate gene transcription, cell death, cell proliferation, drug response, and protein phosphorylation. AOF's active ingredients, Chrysin, Isocyperol, Izalpinin, Linolenic acid, CHEMBL489541, Oxyphyllenone A, Oxyphyllenone B, and Oxyphyllol C, show high affinity to targets, including PPARG, ESR1, and AKT1. These findings provide a new basis for AOF application and anti-AD study.

Polyphenols for the Treatment of Ischemic Stroke: New Applications and Insights

Ischemic stroke (IS) is a leading cause of death and disability worldwide. Currently, the main therapeutic strategy involves the use of intravenous thrombolysis to restore cerebral blood flow to prevent the transition of the penumbra to the infarct core. However, due to various limitations and complications, including the narrow time window in which this approach is effective, less than 10% of patients benefit from such therapy. Thus, there is an urgent need for alternative therapeutic strategies, with neuroprotection against the ischemic cascade response after IS being one of the most promising options. In the past few decades, polyphenolic compounds have shown great potential in animal models of IS because of their high biocompatibility and ability to target multiple ischemic cascade signaling pathways, although low bioavailability is an issue that limits the applications of several polyphenols. Here, we review the pathophysiological changes following cerebral ischemia and summarize the research progress regarding the applications of polyphenolic compounds in the treatment of IS over the past 5 years. Furthermore, we discuss several potential strategies for improving the bioavailability of polyphenolic compounds as well as some essential issues that remain to be addressed for the translation of the related therapies to the clinic.

Chrysin promotes angiogenesis in rat hindlimb ischemia: Impact on PI3K/Akt/mTOR signaling pathway and autophagy

Limb ischemia occurs due to obstruction of blood perfusion to lower limbs, a manifestation that is associated with peripheral artery disease (PAD). Angiogenesis is important for adequate oxygen delivery. The present study investigated a potential role for chrysin, a naturally occurring flavonoid, in promoting angiogenesis in hindlimb ischemia (HLI) rat model. Rats were allocated into four groups: (1) sham-operated control, (2) HLI: subjected to unilateral femoral artery ligation, (3) HLI + chrysin: received 100 mg/kg, i.p. chrysin immediately after HLI, and (4) HLI + chrysin + rapamycin: received 6 mg/kg/day rapamycin i.p. for 5 days then subjected to HLI and dosed with 100 mg/kg chrysin, i.p. Rats were killed 18 h later and gastrocnemius muscles were collected and divided into parts for (1) immunohistochemistry detection of CD31 and CD105, (2) qRT-PCR analysis of eNOS and VEGFR2, (3) colorimetric analysis of NO, (4) ELISA estimation of TGF-β, VEGF, ATG5 and Beclin-1, and (5) Western blot analysis of p-PI3K, PI3K, p-Akt, Akt, p-mTOR, mTOR, and HIF-1α. Chrysin significantly enhanced microvessels growth in HLI muscles as indicated by increased CD31 and CD105 levels and decreased TGF-β. Chrysin's proangiogenic effect is potentially mediated by increased VEGF, VEGFR2 and activation of PI3K/AKT/mTOR pathway, which promoted eNOS and NO levels as it was reversed by the mTOR inhibitor, rapamycin. Chrysin also inhibited autophagy as it decreased ATG5 and Beclin-1. The current study shows that chrysin possesses a proangiogenic effect in HLI rats and might be useful in patients with PAD.

Myosin Light Chain Kinase Modulates to Improve Myocardial Hypoxia/Reoxygenation Injury

Objective

The aim of this study was to evaluate whether myosin light chain kinase (MLCK) knockdown attenuated H9C2 cell hypoxia/reoxygenation (H/R) injury and downstream signaling pathway.

Methods

The MLCK expression in H/R injury model H9C2 cell was determined by western blot and qRT-PCR. H/R cells were transfected with si-MLCK in the presence of P38 inhibitor (SB203580) or ERK inhibitor (U0126). Then, cell apoptosis was verified by flow cytometry. Apoptosis-related proteins were detected by western blot. The contents of reactive oxygen species (ROS), lactate dehydrogenase (LDH), superoxide dismutase (SOD), interleukin-6 (IL-6), interleukin (IL)-1β (IL-1β), and tumor necrosis factor-α (TNF-α) were measured using flow cytometry and colorimetric assays, respectively.

Results

MLCK expression was higher in H/R cells. Knockdown of MLCK diminished the amounts of ROS, LDH, IL-6, IL-1β, and TNF-α and elevated the release of SOD in H/R model H9C2 cells. Additionally, H/R injury induced the cumulative expression and phosphorylation of ERK and the phosphorylation of P38, whereas MLCK siRNA-treated cells showed decreased ERK1/2 and P38 activation. Inversely, P38 inhibitor (SB203580) and ERK inhibitor (U0126) could reverse the cardioprotective effects induced by si-MLCK.

Conclusion

MLCK knockdown attenuated H/R injury in H9C2 cells via regulating the ERK/P38 signaling pathway. MLCK/ERK/p38 axis may provide novel insight into therapeutic targets to restrain I/R injury caused by revascularization therapy after acute myocardial infarction.

Chrysin, which targets PLAU, protects PC12 cells from OGD/R-stimulated damage through repressing the NF-κB signaling pathway

Cerebral ischemia reperfusion injury (CIRI) is a great challenge for the patients with brain ischemia, but its pathophysiological mechanism has not been clearly explored. This study aims to decipher the effect of chrysin and plasminogen activator urokinase (PLAU) in CIRI. The immune-related genes were collected from the ImmPort website, and the differentially expressed genes were determined based on the Gene Expression Omnibus (GEO) database. PC12 cells were used to establish an ischemic stroke model under the condition of oxygen-glucose deprivation and reoxygenation (OGD/R). Small interfering RNA strategy was employed to knock down the PLAU expression of PC12 cells. The proliferation and apoptosis rates of PC12 cells treated by OGD/R or/and chrysin were detected with Cell Counting Kit 8 (CCK-8) and flow cytometry. The protein and mRNA expressions were measured using western blotting and quantitative reverse transcription polymerase chain reaction (qRT-PCR). PLAU was identified as a candidate for CIRI treatment and expressed at higher levels in CIRI tissues compared with that in normal controls. Chrysin was determined as a crucial agent that could decrease the expression of PLAU. Chrysin significantly promoted the cell proliferation, inhibited the protein levels of PLAU, p–NF–κB, and p-IKκB in PC12 cells after OGD/R. Silencing of PLAU strengthened the protective effect of chrysin on PC12 cells treated by OGD/R, including the improvement of cell viability and suppression of apoptosis. Chrysin inactivated the NF-κB pathway via targeting PLAU in OGD/R-stimulated PC12 cells. Chrysin prevented PC12 cells from OGD/R-stimulated damage via decreasing PLAU expression and inactivating the NF-κB signaling pathway.

Macamide B Pretreatment Attenuates Neonatal Hypoxic-Ischemic Brain Damage of Mice Induced Apoptosis and Regulates Autophagy via the PI3K/AKT Signaling Pathway

Lepidium meyenii (maca) is an annual or biennial herb from South America that is a member of the genus Lepidium L. in the family Cruciferae. This herb possesses antioxidant and antiapoptotic activities, enhances autophagy functions, prevents cell death, and protects neurons from ischemic damage. Macamide B, an effective active ingredient of maca, exerts a neuroprotective effect on neonatal hypoxic-ischemic brain damage (HIBD), but the mechanism underlying its neuroprotective effect is not yet known. The purpose of this study was to explore the effect of macamide B on HIBD-induced autophagy and apoptosis and its potential neuroprotective mechanism. The modified Rice-Vannucci method was used to induce HIBD in 7-day-old (P7) macamide B- and vehicle-pretreated pups. TTC staining was performed to evaluate the cerebral infarct volume in pups, the brain water content was measured to evaluate the neurological function of pups, neurobehavioural testing was conducted to assess functional recovery after HIBD, TUNEL and FJC staining was performed to detect cellular autophagy and apoptosis, and Western blot analysis was used to detect the levels of proteins in the pro-survival phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) signaling pathway and autophagy and apoptosis-related proteins. Macamide B pretreatment significantly decreases brain damage and improves the recovery of neural function after HIBD. At the same time, macamide B pretreatment activates the PI3K/AKT signaling pathway after HIBD, enhances autophagy, and reduces hypoxic-ischemic (HI)-induced apoptosis. In addition, 3-methyladenine (3-MA), an inhibitor of the PI3K/AKT signaling pathway, significantly inhibits the increase in autophagy levels, aggravates HI-induced apoptosis, and reverses the neuroprotective effect of macamide B on HIBD. Our data indicate that a macamide B pretreatment might regulate autophagy through the PI3K/AKT signaling pathway, thereby reducing HIBD-induced apoptosis and exerting neuroprotective effects on neonatal HIBD. Macamide B may become a new drug for the prevention and treatment of HIBD.

Effect of Chrysin on Endoplasmic Reticulum Stress in a Rat Model of Testicular Torsion

BACKGROUND

The purpose of this study was to evaluate the possible therapeutic effect of chrysin (CHS) on testicular torsion/detorsion (T/D) injury in vivo through the mechanisms of oxidative stress and endoplasmic reticulum stress (ERS).

METHODS

Eighteen male rats were divided into three groups of six subjects in each group: control, T/D and T/D + CHS (100 mg/kg). To evaluate the degree of oxidative stress, tissue malondialdehyde (MDA), total oxidant status (TOS) and total antioxidant status (TAS) levels were determined using colorimetric methods, while tissue superoxide dismutase (SOD) levels were determined using an ELISA kit. To evaluate the degree of ERS, tissue glucose regulatory protein 78 (GRP78), activating transcription factor 6 (ATF6) and C/EBP homologous protein (CHOP) levels were determined using ELISA kits. Johnsen's testicle scoring system was used for histological evaluation.

RESULTS

In the T/D group, it is determined that statistically significant decreasing in the levels of TAS, SOD and Johnsen score, and increasing in TOS, MDA, GRP78, ATF6 and CHOP levels compared to control group (p < 0.05). CHS administration statistically significantly restored this T/D-induced damage (p < 0.05).

CONCLUSION

This is the first study to show that CHS prevent T/D-induced testicular damage through its ERS inhibitor activity. More comprehensive studies are needed to understand the underlying mechanisms.

Supplemental data for this article is available online at https://doi.org/10.1080/08941939.2021.2015489 .

Chrysin restores memory deficit in hypothyroidism mice: Behavioral, neurochemical and computational approaches involving the neurotrophinergic system

Hypothyroidism is a condition that affects multiple systems, including the central nervous system, causing, for example, cognitive deficits closely related to Alzheimer's disease. The flavonoid chrysin is a natural compound associated with neuronal improvement in several experimental models. Here, we evaluated the effect of chrysin on cognitive impairment in hypothyroid female mice by exploring neuroplasticity. Hypothyroidism was induced by continuous exposure to 0.1% methimazole (MTZ) in drinking water for 31 days. On the 32nd day, the animals showed low plasma levels of thyroid hormones (hypothyroid mice) than the control group (euthyroid mice). Subsequently, mice were intragastrically administered with vehicle or chrysin (20 mg/kg) once a day for 28 consecutive days. At the end of the treatments, behavioral tests were performed: open-field test (OFT) and morris water maze (MWM). Then, the levels of neurotrophins (BDNF and NGF) in the hippocampus and prefrontal cortex were measured and tested the affinity of chrysin with neurotrophinergic receptors through molecular docking. Hypothyroid mice showed memory deficit in the MWM and reduced neurotrophins levels in the hippocampus and prefrontal cortex, meanwhile, the chrysin treatment was able to reversed the deficit of spatial memory function and increased the levels of BDNF in hipocamppus and NGF in both structures. Additionally, molecular docking analysis showed that chrysin potentially binds to the active site of the TrkA, TrkB, and p75NTR receptors. Together, these findings suggest that chrysin reversed behavioral and neurochemical alterations associated with memory deficit induced by hypothyroidism, possibly by modulating synaptic plasticity in the neurotrophinergic system.

Chrysin attenuates sodium arsenite-induced nephrotoxicity in rats by suppressing oxidative stress and inflammation

BACKGROUND

We aimed to study the beneficial property of chrysin (CHR) by targeting its antioxidant and anti-inflammatory effects on nephrotoxicity induced by sodium arsenite (SA).

MATERIALS & METHODS

We have used the 35 male Wistar rats in five equal groups (n = 7). Normal saline in (5 ml/kg; p.o.; 21 days) was given to the control group. Sodium arsenite (10 mg/kg; p.o.; 14 days) was given to the SA group. CHR (25, 50 and 100 mg/kg; p.o.; 21 days) and SA (10 mg/kg; p.o.; 14 days from the 7th day of the experiment) was given to the SA + CHR 25, 50 and 100 groups. On the 22nd day of the experiment, the animals' bloods and kidneys were taken, and then we have performed functional, biochemical and histological assessment.

RESULTS

CHR pre- and alongside administration (more potently at dose of 100 mg/kg) with SA reduced the SA-induced alterations in serum creatinine and blood urine nitrogen levels. Increased levels of protein carbonyl, myeloperoxidase, malondialdehyde and nitric oxide in kidney tissue were decreased by CHR treatment. CHR administration increased the levels of glutathione and activities of glutathione peroxidase, catalase and superoxide dismutase in renal tissue. Moreover, treatment with CHR reduced the levels of inflammatory mediators including interleukin 1 beta and tumor necrosis factor alpha in renal tissue. The renal histological lesions induced SA were mitigated by CHR treatment in dose dependent manner.

CONCLUSION

The results of present study suggested that administration of CHR before and alongside with SA attenuated the renal toxic effects of SA via antioxidative stress and anti-inflammatory effects.

Liposomal chrysin attenuates hepatic ischaemia-reperfusion injury: possible mechanism via inhibiting NLRP3 inflammasome

OBJECTIVES

The chrysin has properties of low aqueous solubility, bioavailability and absorption, and its effect on hepatic ischaemia-reperfusion (HIR) remains unclear. Thus, we prepared a liposomal chrysin (LC) and explored its effect and potential mechanism on HIR.

METHODS

A thin-film dispersion method was used to prepare LC, and a mouse HIR model was used. Mice were pre-treated with LC (100 mg/kg) or placebo by gavage feeding at 16.5 h, 8.5 h, 0.5 h before modelling.

RESULTS

The average particle sizes, polydispersity index, zeta potential, encapsulation efficiency and drug loading of LC were 129 ± 13.53 nm, 0.265 ± 0.021, -34.46 ± 4.14 mV, 95.03 ± 2.17%, 16.4 ± 0.8%. The concentration of chrysin in plasma and liver tissue by LC administration increased 2.54 times and 1.45 times. LC pre-treatment reduced HIR-induced liver injury and inhibited cell apoptosis. Besides, LC pre-treatment decreased reactive oxygen species and malondialdehyde and inhibited the inflammation response indicated by lower IL-6, TNF-α, infiltration of neutrophils. Further, LC pre-treatment significantly decreased NLRP3 activation, evidenced by reduced cleaved caspase-3, NLRP3, ASC, cleaved caspase-1 and IL-1β expression.

CONCLUSIONS

LC has good biocompatibility, and it could attenuate HIR-induced injury. Its mechanism was associated with NLRP3 inflammasome inhibition, and LC might be an effective drug for treating and preventing HIR-induced injury.

Neuroprotective Potential of Chrysin: Mechanistic Insights and Therapeutic Potential for Neurological Disorders

Chrysin, a herbal bioactive molecule, exerts a plethora of pharmacological effects, including anti-oxidant, anti-inflammatory, neuroprotective, and anti-cancer. A growing body of evidence has highlighted the emerging role of chrysin in a variety of neurological disorders, including Alzheimer’s and Parkinson’s disease, epilepsy, multiple sclerosis, ischemic stroke, traumatic brain injury, and brain tumors. Based on the results of recent pre-clinical studies and evidence from studies in humans, this review is focused on the molecular mechanisms underlying the neuroprotective effects of chrysin in different neurological diseases. In addition, the potential challenges, and opportunities of chrysin’s inclusion in the neurotherapeutics repertoire are critically discussed.

Protective effects of dexmedetomidine on cerebral ischemia/reperfusion injury via the microRNA-214/ROCK1/NF-κB axis

BACKGROUND

Cerebral ischemia/reperfusion injury (CIRI) is a complication of surgical procedure associated with high mortality. The protective effect of dexmedetomidine (DEX) on CIRI has been explored in previous works, yet the underlying molecular mechanism remains unclear. Our study explored the protective effect of DEX and its regulatory mechanism on CIRI.

METHODS

A CIRI rat model was established using middle cerebral artery occlusion (MCAO). Neurological deficit scores for rats received MCAO modeling or DEX treatment were measured. Cerebral infarction area of rats was detected by TTC staining, while damage of neurons in hippocampal regions of rats was determined by hematoxylin-eosin (HE) staining. Apoptosis rate of neurons in hippocampal regions was examined by TUNEL staining. The dual-luciferase assay was performed to detect the binding of microRNA-214 (miR-214) to Rho-associated kinase 1 (ROCK1).

RESULTS

DEX treatment significantly reduced infarction area of MCAO rats and elevated miR-214 expression. Injection of miR-214 inhibitor attenuated the effect of DEX in MCAO rats by increasing the area of cerebral infarction in rats and apoptosis rate of hippocampal neurons. ROCK1 was targeted and negatively regulated by miR-214. The overexpression of ROCK1 led to activation of NF-κB to aggravate CIRI.

CONCLUSION

Therapeutic effects of DEX on CIRI was elicited by overexpressing miR-214 and impairing ROCK1 expression and NF-κB activation. Our finding might provide novel insights into the molecular mechanism of DEX in rats with CIRI.

Chrysin Improves Glucose and Lipid Metabolism Disorders by Regulating the AMPK/PI3K/AKT Signaling Pathway in Insulin-Resistant HepG2 Cells and HFD/STZ-Induced C57BL/6J Mice

Natural products with minor side effects have been reported to be an effective adjuvant therapy for glucose and lipid metabolism disorders. Chrysin, a flavone, has a wide range of physiological effects, such as antioxidant, anti-inflammatory, anti-diabetes, anti-hyperlipidemia, and hepatoprotective. This study was designed to explore the effects and mechanism of chrysin on metabolic syndrome using insulin-resistant HepG2 cells and HFD/STZ-induced C57BL/6J mice. The results indicated that chrysin significantly decreased insulin resistance, oxidative stress, inflammation, and liver injury. In addition, chrysin improved glycogen synthesis and fatty acid oxidation and inhibited gluconeogenesis and fatty acid synthesis by regulating GSK3β, G6Paes, PEPCK, SREBP1, FAS, and ACC1. Furthermore, the results of western blot and real-time PCR experiments demonstrated that chrysin modulated glucose and lipid metabolism through the AMPK/PI3K/AKT signaling pathway. Treatment with the AMPK inhibitor verified that AMPK activation is positively correlated with chrysin activity on glycolipid metabolism. This study confirms that chrysin is a potential treatment for glucose and lipid metabolism disorders.

Inflammation-Mediated Angiogenesis in Ischemic Stroke

Stroke is the leading cause of disability and mortality in the world, but the pathogenesis of ischemic stroke (IS) is not completely clear and treatments are limited. Mounting evidence indicate that neovascularization is a critical defensive reaction to hypoxia that modulates the process of long-term neurologic recovery after IS. Angiogenesis is a complex process in which the original endothelial cells in blood vessels are differentiated, proliferated, migrated, and finally remolded into new blood vessels. Many immune cells and cytokines, as well as growth factors, are directly or indirectly involved in the regulation of angiogenesis. Inflammatory cells can affect endothelial cell proliferation, migration, and activation by secreting a variety of cytokines via various inflammation-relative signaling pathways and thus participate in the process of angiogenesis. However, the mechanism of inflammation-mediated angiogenesis has not been fully elucidated. Hence, this review aimed to discuss the mechanism of inflammation-mediated angiogenesis in IS and to provide new ideas for clinical treatment of IS.

Artesunate Provides Neuroprotection against Cerebral Ischemia-Reperfusion Injury via the TLR-4/NF-κB Pathway in Rats

Inflammation has an important role in ischemia-reperfusion (I/R) injury. Artesunate (ART) has anti-microbial and anti-inflammatory pharmacological activities, and it is used for various types of serious malaria, including cerebral malaria. ART maintains a high concentration in the brain but little is known about the neuroprotective effect of ART against brain I/R injury. We studied the neuroprotection of ART against brain I/R injury and its underlying mechanism. In this study, rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h. After 24 h of reperfusion, neurological deficits, cerebrum water content, infarct volume, hematoxylin-eosin (H&E)-staining, myeloperoxidase (MPO) activity, and proinflammatory cytokine levels were measured. Administration of 20, 40, 80, and 160 mg/kg ART intraperitoneally (i.p.) 10 min after MCAO significantly decreased brain water content and improved neurological deficits in a dose-dependent manner. An 80 mg/kg dosage was optimal. ART significantly reduced infarct volume, suppressed MPO activity and diminished the expressions of toll-like receptor (TLR)-4, MyD88, nuclear factor-κB (NF-κB), tumor necrosis factor (TNF)-α, and interleukin (IL)-6 in the area of the ischemic cortex. The neuroprotective action of ART against focal cerebral I/R injury might be due to the attenuation of inflammation through the TLR-4/NF-κB pathway.

FABP4 alleviates endoplasmic reticulum stress-mediated ischemia-reperfusion injury in PC12 cells via regulation of PPARγ

Ischemic stroke is a life-threatening complication with a high rate of morbidity. Circulating fatty acid binding protein 4 (FABP4) has been reported to be associated with the outcome of acute ischemic stroke. The present study aimed to illustrate the function of FABP4 in ischemic stroke. PC12 cells exposed to oxygen glucose deprivation/reoxygenation (OGD/R) were used to mimic ischemia-reperfusion (I/R) injury in ischemic stroke. Cell viability was estimated using a Cell Counting Kit-8 assay. The expression of FABP4 in PC12 cells under OGD/R was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). PC12 cells were transfected with FABP4 small interfering RNA (siRNA), inflammatory cytokines and reactive oxygen species (ROS) were determined via RT-qPCR and ROS assay kit. Western blotting was performed to detect endoplasmic reticulum stress (ERS)-related proteins and peroxisome proliferator-activated receptor γ (PPARγ). Flow cytometry was used to evaluate the cell apoptotic rate. The expression of FABP4 increased gradually with the prolongation of reoxygenation within 8 h. FABP4-knockdown inhibited the transcription of inflammatory cytokines, the production of ROS and decreased cell apoptosis. Furthermore, decreased ERS-related proteins and increased PPARγ were estimated in PC12 cells transfected with FABP4 siRNA. PPARγ inhibitor GW9662 weakened the anti-apoptotic effect of FABP4-knockdown. Taken together, these results indicated that FABP4-knockdown suppressed cell apoptosis via relieving ERS; this effect was reversed by treatment of GW9662.

Neuroprotective Effects of Chrysin Mediated by Estrogenic Receptors Following Cerebral Ischemia and Reperfusion in Male Rats

Introduction

Ischemic stroke is one of the leading causes of morbidity and mortality worldwide. Neuroprotective strategies were reported to attenuate cognitive deficits after ischemic incidents. Here we studied the neuroprotective potential of chrysin in a rat model of cerebral Ischemia/Reperfusion (I/R) in the presence or absence of Estrogen Receptors (ERs).

Methods

Adult male Wistar rats were pretreated with chrysin (CH) (CH; 30 mg/kg; gavage; for 21 consecutive days) alone or with selective ERs antagonists (ERα antagonist MPP; ERβ antagonist PHTPP; IP) or nonselective ERs antagonist (ICI182780; IP). Then, the bilateral common carotid arteries were occluded for 20 min, which was followed by 72 h reperfusion. Subsequently, cognitive performance was evaluated by Morris Water Maze (MWM) and shuttle box tasks, and afterward, their hippocampi were removed for ELISA assays and H&E staining. Oxidative indicators Malondialdehyde (MDA) and Glutathione Peroxidase (GPx), as well as inflammation mediators interleukin (IL)-1β and tumor necrosis factor-alpha (TNFα), were measured using commercial kits.

Results

Results of the current study showed that the anti-oxidative and anti-inflammatory properties of CH are possible mechanisms that could improve cognitive deficits and prevent neuronal cell death following I/R (P<0.001). These effects were reversed by ICI182780 (P>0.05). Furthermore, when chrysin was co-treated with ERβ antagonist, PHTPP showed a weak neuroprotective effect in I/R rats. However, these parameters were not significantly different when chrysin was combined with ERα antagonist MPP.

Conclusion

Our data confirm that chrysin could potentially serve as a neuroprotective agent against devastating effects of cerebral I/R injury, which may be mediated via its interaction with ERs, especially ERβ.

Effect of Eriocalyxin B on prostatic inflammation and pelvic pain in a mouse model of experimental autoimmune prostatitis

BACKGROUND

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a common disease in males. Eriocalyxin B (EriB), a natural diterpenoid purified from Isodon eriocalyx var. laxiflora, was previously reported to have antitumor effects via multiple immune-related pathways. In this study, we investigated the effect of EriB on CP/CPPS using a mouse model of experimental autoimmune prostatitis (EAP) and explored its potential mechanisms.

METHODS

The EAP model was established in nonobese diabetic mice by intradermal injecting a mixture of prostate antigens and Complete Freund's Adjuvant on days 0 and 28. Then, EAP mice received daily intraperitoneal injections of EriB (5 or 10 mg/kg/d) for 14 days, from days 28 to 42 (EAP+EriB5 or EAP+EriB10 groups). The histopathological appearance of the prostate tissues was evaluated. Chronic pelvic pain development was assessed by cutaneous allodynia. Inflammatory cytokines were measured by enzyme-linked immunosorbent assay tests. We then explored anti-inflammatory potential mechanisms of EriB by studying the effects of PI3K inhibitor wortmannin (EAP+EriB10+Wort group) and NF-κB inhibitor SC75741 (EAP+EriB10+SC group) on prostate inflammation and pelvic pain using this model.

RESULTS

Histological analyses revealed significant prostate inflammation in EAP mice compared with control mice. Significantly increased pelvic pain was detected in EAP mice (P < .05). Compared with the EAP+Veh group, chronic pain development, histological appearance, and cytokine levels demonstrated that EriB could alleviate the severity of EAP in a dose-dependent manner though upregulation of the PI3K/Akt/mTOR pathway and downregulation of the NF-κB pathway. Further mechanism research demonstrated that the PI3K/AKT/mTOR pathway could be blocked by wortmannin, but was not affected by SC75741. In addition, the NF-κB pathway could be further inhibited by SC75741 compared with the EAP+EriB10+Veh group. However, wortmannin could reactivate the NF-κB pathway, indicating that the PI3K/AKT/mTOR pathway negatively regulates the NF-κB pathway during EriB treatment.

CONCLUSIONS

The results of the present study suggested that EriB could alleviate the severity of prostatic inflammation and pelvic pain in an EAP mouse model. These findings may broaden the value of EriB as a promising candidate for the treatment of CP/CPPS.

Nobiletin alleviates ischemia/reperfusion injury in the kidney by activating PI3K/AKT pathway

Recent studies have demonstrated that nobiletin (NOB) displays anti-oxidative and anti-apoptotic efficacies against multiple pathological insults. However, the potential effects of NOB on the injury caused by ischemia and reperfusion (I/R) in the kidney remain undetermined. In the present study, I/R injury was elicited by right kidney removal and left renal pedicel clamping for 45 min, followed by reperfusion for 24 h. NOB was added at the start of reperfusion. Histological examination, detection of biomarkers in plasma, and measurement of apoptosis induced by endoplasmic reticulum stress (ERS) were used to evaluate renal injury. Additionally, the PI3K/AKT inhibitor LY294002 was also used in mechanistic experiments. NOB pre-treatment significantly reduced renal damage caused by I/R injury, as indicated by decreased serum levels of creatine, blood urea nitrogen and tubular injury scores. Furthermore, NOB inhibited elevated ERS-associated apoptosis, as evidenced by reduced apoptotic rates and ERS-related signaling molecules (such as, C/EBP homologous protein, caspase-12 and glucose-regulated protein of 78 kDa). NOB increased phosphorylation of proteins in the PI3K/AKT pathway. The inhibition of PI3K/AKT signaling with pharmacological inhibitors could reverse the beneficial effects of NOB during renal I/R insult. In conclusion, NOB pre-treatment may alleviate I/R injury in the kidney by inhibiting reactive oxygen species production and ERS-induced apoptosis, partly through the PI3K/AKT signaling pathway.

TMEM16A-encoded anoctamin 1 inhibition contributes to chrysin-induced coronary relaxation

BACKGROUND

Chrysin, a natural flavonoid available in honey, propolis and medicinal plants, has been shown to be vasorelaxant in some vascular beds. Proper intake of an alimental vasodilator as a food additive may be a promising strategy for prevention and treatment of coronary spasmodic disorders.

PURPOSE

TMEM16A-encoded anoctamin 1 (ANO1), a Ca²⁺ activated Cl^- channel (CaCC), plays an important role in the modulation of vascular tone. We tested the possibility that inhibition of CaCCs contributes to chrysin-induced coronary arterial relaxation.

METHODS

The vascular tone of the rat coronary artery (RCA) was recorded with a wire myograph. CaCC currents were assessed using whole-cell patch clamp in arterial smooth muscle cell (ASMC) freshly isolated from RCAs. An inhibitor study was performed to explore the mechanisms underlying the vasomotor and electrophysiological effects of chrysin.

RESULTS

Pre-incubation with chrysin depressed the contractions elicited by thromboxane A2 analog U46619, vasopressin (VP), depolarization and extracellular Ca²⁺ elevation/depolarization without significant preference among these vasoconstrictors. Besides, chrysin inhibited both intracellular Ca²⁺ release-dependent and extracellular Ca²⁺ influx-dependent components of contractions induced by U46619 or VP. In RCAs pre-contracted with U46619, VP or KCl, chrysin elicited concentration-dependent relaxations, which were weakened by Cl^- -deprivation. The electrophysiological study showed that chrysin reduced ANO1-antibody-sensitive CaCC currents and depressed CaCC increments induced by U46619. Inhibitor study showed that both the vasorelaxation and the CaCC current reduction induced by chrysin were attenuated by blocking CaCCs and inhibiting cAMP/PKA and NO/PKG pathways.

CONCLUSION

The present findings indicate that inhibition of RCA ASMC CaCC currents, which may be consequential following intracellular Ca²⁺ availability reduction and activation of cAMP/PKA and NO/cGMP signaling pathways, contributes to chrysin-induced RCA relaxation.

Tomentosin inhibit cerebral ischemia/reperfusion induced inflammatory response via TLR4/ NLRP3 signalling pathway - in vivo and in vitro studies

Stoke is a global threat, leading to 50 % of deaths worldwide and it causes permanent disability to about 5 million individuals globally each year. In this study, we assessed the potency of tomentosin to inhibit the neuroinflammation in in vivo and in vitro models. The Sprague Dawley rats were pretreated with 25 mg/kg bodyweight (b.wt) and 50 mg/kg b.wt of tomentosin for seven days followed by induction of cerebral ischemic reperfusion. The brain edema and cerebral infractions were analyzed. The levels of antioxidants and the interleukins were measured by standard methods. The NLRP3 signaling proteins expression was evaluated using qPCR analysis. In vitro studies were performed in SH-SY5Y-cells pretreated with tomentosin and subjected to OGD-R treatment. Our results depicts tomentosin scavenges the free radicals, enhances antioxidant system, inhibits the NLRP3 signaling. In vitro results substantiates with in vivo results. To conclude, our in vivo and in vitro results confirm tomentosin may be potent alternative for existing antistroke drugs.

Dietary Flavonoids in p53-Mediated Immune Dysfunctions Linking to Cancer Prevention

The p53 protein plays a central role in mediating immune functioning and determines the fate of the cells. Its role as a tumor suppressor, and in transcriptional regulation and cytokine activity under stress conditions, is well defined. The wild type (WT) p53 functions as a guardian for the genome, while the mutant p53 has oncogenic roles. One of the ways that p53 combats carcinogenesis is by reducing inflammation. WT p53 functions as an anti-inflammatory molecule via cross-talk activity with multiple immunological pathways, such as the major histocompatibility complex I (MHCI) associated pathway, toll-like receptors (TLRs), and immune checkpoints. Due to the multifarious roles of p53 in cancer, it is a potent target for cancer immunotherapy. Plant flavonoids have been gaining recognition over the last two decades to use as a potential therapeutic regimen in ameliorating diseases. Recent studies have shown the ability of flavonoids to suppress chronic inflammation, specifically by modulating p53 responses. Further, the anti-oxidant Keap1/Nrf2/ARE pathway could play a crucial role in mitigating oxidative stress, leading to a reduction of chronic inflammation linked to the prevention of cancer. This review aims to discuss the pharmacological properties of plant flavonoids in response to various oxidative stresses and immune dysfunctions and analyzes the cross-talk between flavonoid-rich dietary intake for potential disease prevention.

Chrysin Attenuates the NLRP3 Inflammasome Cascade to Reduce Synovitis and Pain in KOA Rats

Purpose

Our recent reports have revealed that inhibiting NLRP3 activation reduces synovial inflammation and fibrosis in knee osteoarthritis (KOA). Synovial inflammation is involved the entire process of KOA and promotes the progression of KOA. Natural flavonoid Chrysin from Scutellariae Radix, a traditional Chinese medicine, exhibits multifarious biological activities and potentially has protective activity against osteoarthritis. However, the mechanism of Chrysin in the treatment of synovial inflammation remains elusive. The purpose of our research was to explore the anti-inflammatory effects of Chrysin on KOA, which was induced by monoiodoacetic acid (MIA) in rats by targeting the NLRP3 inflammasome in the hopes of identifying an effective drug to treat KOA.

Methods

The MIA-induced KOA model was used to evaluate the cold pain threshold and paw withdrawal threshold (PWT) of joints after MIA (40 mg/mL) injection into the knee joints. Microscopically, we used LPS (5 ug/mL) and ATP (4 mmol/L) to stimulate fibroblast-like synovial cells (FLSs) to explore the underlying mechanisms and effects of Chrysin. Two staining methods, H&E and Sirius Red, were applied to assess histopathological changes in synovial membranes. Cellular signal transduction was determined by qRT-PCR and WB. Cytokine expression (inflammatory cytokines and pain-related cytokines) was detected by ELISA. The degree of chronic inflammatory pain was evaluated by c-Fos immunofluorescence.

Results

The results showed that Chrysin not only attenuated synovial inflammation but also reduced the secretion of pain-related factors and increased the PWT and cold pain threshold in rats. Chrysin also inhibited NLRP3 inflammasome activation and increased IL-1β levels to alleviate the synovitis.

Conclusion

Chrysin can relieve knee synovial inflammation and improve pain behavior in KOA rats, which may be related to the ability of Chrysin to inhibit NLRP3 inflammasome activation. Therefore, Chrysin may be developed as a new drug for the treatment of KOA.

Targeting apoptosis and autophagy following spinal cord injury: Therapeutic approaches to polyphenols and candidate phytochemicals

Spinal cord injury (SCI) is a neurological disorder associated with the loss of sensory and motor function. Understanding the precise dysregulated signaling pathways, especially apoptosis and autophagy following SCI, is of vital importance in developing innovative therapeutic targets and treatments. The present study lies in the fact that it reveals the precise dysregulated signaling mediators of apoptotic and autophagic pathways following SCI and also examines the effects of polyphenols and other candidate phytochemicals. It provides new insights to develop new treatments for post-SCI complications. Accordingly, a comprehensive review was conducted using electronic databases including, Scopus, Web of Science, PubMed, and Medline, along with the authors' expertise in apoptosis and autophagy as well as their knowledge about the effects of polyphenols and other phytochemicals on SCI pathogenesis. The primary mechanical injury to spinal cord is followed by a secondary cascade of apoptosis and autophagy that play critical roles during SCI. In terms of pharmacological mechanisms, caspases, Bax/Bcl-2, TNF-α, and JAK/STAT in apoptosis along with LC3 and Beclin-1 in autophagy have shown a close interconnection with the inflammatory pathways mainly glutamatergic, PI3K/Akt/mTOR, ERK/MAPK, and other cross-linked mediators. Besides, apoptotic pathways have been shown to regulate autophagy mediators and vice versa. Prevailing evidence has highlighted the importance of modulating these signaling mediators/pathways by polyphenols and other candidate phytochemicals post-SCI. The present review provides dysregulated signaling mediators and therapeutic targets of apoptotic and autophagic pathways following SCI, focusing on the modulatory effects of polyphenols and other potential phytochemical candidates.

Modulation of glutamate levels and Na+,K+-ATPase activity contributes to the chrysin memory recovery in hypothyroidism mice

Abnormalities in the thyroid hormones, like in hypothyroidism, are closely related to dementia and Alzheimer's disease demonstrating the main symptom of these disorders: memory deficit. In this study we evaluated the effect of chrysin on deficit spatial and aversive memories and the contribution of glutamatergic, cholinergic pathways and Na⁺, K⁺-ATPase activity on hippocampus and prefrontal cortex in hypothyroid adult female mice C57BL/6. Hypothyroidism was induced by the continuous exposure to 0.1% methimazole (MTZ) in drinking water for 31 days. The exposure to MTZ was associated to low plasma levels of thyroid hormones (TH) compared to the control group on the 32nd. Subsequently, euthyroid and MTZ-induced hypothyroid mice received (intragastrically) either vehicle or chrysin (20 mg/kg) once a day for 28 consecutive days. After treatments mice performed the following behavioral assessments: open-field test (OFT), morris water maze (MWM) and passive avoidance test. Additionally, plasma TH levels were measured again, as well as glutamate levels, Na⁺,K⁺-ATPase and acetylcholinesterase (AChE) activities were analyzed in the hippocampus and prefrontal cortex of mice. Mice with hypothyroidism showed a deficit of spatial and aversive memory and chrysin treatment reversed these deficits. It also reduced the levels of glutamate and decreased Na⁺,K⁺-ATPase activity in both cerebral structures in the hypothyroid mice compared with the euthyroid ones, with the exception of glutamate in the hippocampus, which was a partial reversal. AChE activity was not altered by treatments. Together, our results demonstrate that chrysin normalized hippocampal glutamate levels and Na⁺,K⁺-ATPase activity, which could be involved in the reversal of memory deficit.

Chrysin ameliorates hepatic steatosis induced by a diet deficient in methionine and choline by inducing the secretion of hepatocyte nuclear factor 4α-dependent very low-density lipoprotein

We investigated the effects of chrysin (CHR) on nonalcoholic fatty liver disease (NAFLD) in mice. The NAFLD mouse model was established using a diet deficient in methionine and choline (MCD). CHR was shown to attenuate MCD-induced hepatic fat accumulation, increase very low-density lipoprotein (VLDL) secretion, and decrease hepatic oxidative stress in NAFLD mice. Inhibition of oxidative stress or direct suppression of protein kinase C (PKC) by CHR significantly reduced PKC activity in the liver, leading to a decrease in inhibitory phosphorylation of hepatocyte nuclear factor 4α (HNF4α). The resulting activation of HNF4α led to induced transcription of apolipoprotein B and VLDL secretion. Together, these results show that CHR effectively ameliorates MCD-induced fatty liver in NAFLD mice by targeting the hepatic oxidative stress/PKC/HNF4α signaling pathway.