Protective effects of apigenin on LPS-induced endometritis via activating Nrf2 signaling pathway

Therapeutic administration of Luteolin protects against Escherichia coli-derived Lipopolysaccharide-triggered inflammatory response and oxidative injury

Endometritis reduces reproductive effectiveness and leads to significant financial losses in the dairy sector. Luteolin is a natural phyto-flavonoid compound with many biological activities. However, the therapeutic effect of Luteolin against lipopolysaccharides (LPS)-induced endometritis has not yet been explored. A total of eighty female Kunming mice were randomly assigned into four treatment groups (n = 20). Following a successful initiation of the endometritis model by LPS, Luteolin was intraperitoneally administered three times, at six-hour intervals between each injection in the Luteolin groups. The histopathological findings revealed that Luteolin significantly alleviated uterine injury induced by LPS. Moreover, Luteolin suppressed the synthesis of pro-inflammatory mediators [interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α] while promoting the synthesis of an anti-inflammatory mediator (IL-10) altered by LPS. Furthermore, Luteolin significantly mitigated the LPS-induced oxidative stress by scavenging malondialdehyde (MDA) and reactive oxygen species (ROS), accumulation and boosting the capacity of antioxidant enzyme activities such as superoxide dismutase 1 (SOD1), catalase (CAT), and glutathione peroxidase 1 (Gpx1) in the uterine tissue of mice. Additionally, injection of Luteolin markedly increased the expression of Toll-like receptors (TLR) 4 both at mRNA and protein levels under LPS stimulation. Western blotting and ELISA findings demonstrated that Luteolin suppressed the activation of the NF-κB pathway in response to LPS exposure in the uterine tissue of mice. Notably, Luteolin enhanced the anti-oxidant defense system by activating the Nrf2 signaling pathway under LPS exposure in the uterine tissue of mice. Conclusively, our findings demonstrated that Luteolin effectively alleviated LPS-induced endometritis via modulation of TLR4-associated Nrf2 and NF-κB signaling pathways.

Role of Bioactive Compounds, Novel Drug Delivery Systems, and Polyherbal Formulations in the Management of Rheumatoid Arthritis

Rheumatoid Arthritis (RA) is an autoimmune disorder that generally causes joint synovial inflammation as well as gradual cartilage and degenerative changes, resulting in progressive immobility. Cartilage destruction induces synovial inflammation, including synovial cell hyperplasia, increased synovial fluid, and synovial pane development. This phenomenon causes articular cartilage damage and joint alkalosis. Traditional medicinal system exerts their effect through several cellular mechanisms, including inhibition of inflammatory mediators, oxidative stress suppression, cartilage degradation inhibition, increasing antioxidants and decreasing rheumatic biomarkers. The medicinal plants have yielded a variety of active constituents from various chemical categories, including alkaloids, triterpenoids, steroids, glycosides, volatile oils, flavonoids, lignans, coumarins, terpenes, sesquiterpene lactones, anthocyanins, and anthraquinones. This review sheds light on the utilization of medicinal plants in the treatment of RA. It explains various phytoconstituents present in medicinal plants and their mechanism of action against RA. It also briefs about the uses of polyherbal formulations (PHF), which are currently in the market and the toxicity associated with the use of medicinal plants and PHF, along with the limitations and research gaps in the field of PHF. This review paper is an attempt to understand various mechanistic approaches employed by several medicinal plants, their possible drug delivery systems and synergistic effects for curing RA with minimum side effects.

Nrf2-mediated therapeutic effects of dietary flavones in different diseases

Oxidative stress (OS) is a pathological status that occurs when the body's balance between oxidants and antioxidant defense systems is broken, which can promote the development of many diseases. Nrf2, a redox-sensitive transcription encoded by NFE2L2, is the master regulator of phase II antioxidant enzymes and cytoprotective genes. In this context, Nrf2/ARE signaling can be a compelling target against OS-induced diseases. Recently, natural Nrf2/ARE regulators like dietary flavones have shown therapeutic potential in various acute and chronic diseases such as diabetes, neurodegenerative diseases, ischemia-reperfusion injury, and cancer. In this review, we aim to summarize nrf2-mediated protective effects of flavones in different conditions. Firstly, we retrospected the mechanisms of how flavones regulate the Nrf2/ARE pathway and introduced the mediator role Nrf2 plays in inflammation and apoptosis. Then we review the evidence that flavones modulated Nrf2/ARE pathway to prevent diseases in experimental models. Based on these literature, we found that flavones could regulate Nrf2 expression by mechanisms below: 1) dissociating the binding between Nrf2 and Keap1 via PKC-mediated Nrf2 phosphorylation and P62-mediated Keap1 autophagic degradation; 2) regulating Nrf2 nuclear translocation by various kinases like AMPK, MAPKs, Fyn; 3) decreasing Nrf2 ubiquitination and degradation via activating sirt1 and PI3K/AKT-mediated GSK3 inhibition; and 4) epigenetic alternation of Nrf2 such as demethylation at the promoter region and histone acetylation. In conclusion, flavones targeting Nrf2 can be promising therapeutic agents for various OS-related disorders. However, there is a lack of investigations on human subjects, and new drug delivery systems to improve flavones' treatment efficiency still need to be developed.

Protective effect of the total flavonoids from Clinopodium chinense against LPS-induced mice endometritis by inhibiting NLRP3 inflammasome-mediated pyroptosis

ETHNOPHARMACOLOGICAL RELEVANCE

Clinopodium chinense (Benth.) O. Kuntze (C. chinense) is a Chinese herbal medicine used in treating gynecological hemorrhagic diseases for hundreds of years. Flavonoids are one kind of the major components in C. chinense. The flavonoids of C. chinense (TFC) have a vital role in treating endometritis but the underlying therapeutic mechanisms of TFC against endometritis have been rarely reported.

AIM OF THE STUDY

To elucidate the therapeutic effect and possible mechanisms of TFC against lipopolysaccharide (LPS)-induced endometritis in vivo and LPS-induced primary mouse endometrial epithelial cells (MEECs) injury in vitro.

MATERIALS AND METHODS

The holistic phytochemicals of the TFC and TFC-contained serum were screened and identified using UPLC-Q-TOF-MS. The model of endometritis was established by intrauterine injection of LPS (5 mg/mL) into female BALB/c mice, and the model mice were treated with TFC for 7 days. The value of MPO was measured by Myeloperoxidase assay kit, the pathological changes in the endometrium were evaluated using H&E staining and transmission electron microscope (TEM), the secretions of IL-18, IL-1β and TNF-α were determined by ELISA kits, the mRNA expressions of IL-18, IL-1β and TNF-α were determined by RT-PCR assay, and the protein levels of TLR4, IKBα, p-IKBα, p65, p-p65, caspase-1, ASC, NLRP3 and GSDMD were measured by Western blot. Subsequently, MEECs were isolated from the uterus of pregnant female mice, injured by LPS for 24 h and incubated with the TFC-contained serum. Finally, cell viability, LDH release, hoechst 33342/PI staining, immunofluorescence staining, scanning electron microscope observation, ELISA assay, RT-PCR detection and Western blot analysis were carried out to further validate the therapeutic effect and the underlying mechanisms of TFC.

RESULTS

A total of 6 compounds in the plasma of mice after being intragastric administrated of TFC were identified. The results in vivo showed that TFC significantly reduced MPO value and alleviated pathological injury of the endometrium. Furthermore, TFC significantly decreased the serum IL-18, IL-1β and TNF-α levels, and the mRNA levels of IL-18, IL-1β and TNF-α. TFC also inhibited the expressions of TLR4, p-IKBα, p-p65, caspase-1, ASC, NLRP3 and GSDMD. Besides, compared with the model group in MEECs cells, TFC-contained serum prevented pyroptosis, decreased the levels of IL-18 and IL-1β, and inhibited the mRNA expressions of IL-18, IL-1β and GSDMD. TFC-contained serum also reversed the activation of NLRP3 inflammasome caused by nigericin, and restrainted the translocation of NF-κB into nuclear.

CONCLUSIONS

TFC protects mice endometritis from the injury of LPS via suppressing the activation of NLRP3 inflammasome and pyroptosis, the underlying mechanisms of which were related to restraining the TLR4/NF-κB/NLRP3 pathway activation.

Transcription Factor Nrf2 Modulates Lipopolysaccharide-Induced Injury in Bovine Endometrial Epithelial Cells

Endometritis in high-yield dairy cows adversely affects lactation length, milk quality, and the economics of dairy products. Endoplasmic reticulum stress (ERS) in bovine endometrial epithelial cells (BEECs) occurs as a consequence of diverse post-natal stressors, and plays a key role in a variety of inflammatory diseases. Nuclear-factor-erythroid-2-related factor 2 (Nrf2) is an important protective regulatory factor in numerous inflammatory responses. However, the mechanism by which Nrf2 modulates inflammation by participating in ERS remains unclear. The objective of the present study was to explore the role of Nrf2 in lipopolysaccharide (LPS)-induced injury to BEECs and to decipher the underlying molecular mechanisms of this injury. The expression of Nrf2- and ERS-related genes increased significantly in bovine uteri with endometritis. Isolated BEECs were treated with LPS to stimulate the inflammatory response. The expression of Nrf2 was significantly higher in cells exposed to LPS, which also induced ERS in BEECs. Activation of Nrf2 led to enhanced expression of the genes for the inflammation markers TNF-α, p65, IL-6, and IL-8 in BEECs. Moreover, stimulation of Nrf2 was accompanied by activation of ERS. In contrast, Nrf2 knockdown reduced the expression of TNF-α, p65, IL-6, and IL-8. Additionally, Nrf2 knockdown decreased expression of ERS-related genes for the GRP78, PERK, eIF2α, ATF4, and CHOP proteins. Collectively, our findings demonstrate that Nrf2 and ERS are activated during inflammation in BEECs. Furthermore, Nrf2 promotes the inflammatory response by activating the PERK pathway in ERS and inducing apoptosis in BEECs.

Protective effects of chicoric acid on LPS-induced endometritis in mice via inhibiting ferroptosis by Nrf2/HO-1 signal axis

Chicoric acid (CA), a natural phenolic acid extracted from Mediterranean vegetable chicory, has anti-oxidative effect. We aimed to investigate the effects of CA on endometritis and clarify the underlying mechanism. C57BL/6 mice were divided into five groups: control group, LPS group, and LPS + CA groups. All mice except control group were infused of LPS into the uterus. The mice of LPS + CA groups were intraperitoneally injected CA 1 h before LPS challenge. CA significantly alleviatedLPS-induced pathological damage, MPO activity, and inflammatory cytokine production. CA significantly suppressed ferroptosis in LPS-induced endometritis. CA also attenuated LPS-induced NF-κB activation. Furthermore, Nrf2 and HO-1 expression were increased by CA. Moreover, the inhibition of CA on LPS-induced endometritis and ferroptosis were markedly prevented in Nrf2 knockdown mice. In conclusion, the results suggested CA protected mice against LPS-induced endometritisthrough inhibiting ferroptosis via Nrf2/HO-1 signaling pathway.

Antioxidant and anti-inflammation effects of dietary phytochemicals: The Nrf2/NF-κB signalling pathway and upstream factors of Nrf2

Oxidative stress (OS) is created by an imbalance between reactive oxygen species and antioxidant levels. OS promotes inflammation and is associated with many diseases, such as neurodegenerative disorders, diabetes, and cardiovascular disease. Nrf2 and NF-κB are critical in the cellular defence against OS and the regulators of inflammatory responses, respectively. Recent studies revealed that the Nrf2 signalling pathway interacts with the NF-κB signalling pathway in OS. More importantly, many natural compounds have long been recognized to ameliorate OS and inflammation via the Nrf2 and/or NF-κB signalling pathway. Thus, we briefly overview the potential crosstalk between Nrf2 and NF-κB and the upstream regulators of Nrf2 and review the literature on the antioxidant and anti-inflammatory effects of dietary phytochemicals (DPs) that can activate these defence systems. The aim is to provide evidence for the development of DPs into functional food for the regulation of the Nrf2/NF-κB signalling pathway by upstream regulators of Nrf2.

LPS-Induced Activation of the cGAS-STING Pathway is Regulated by Mitochondrial Dysfunction and Mitochondrial DNA Leakage in Endometritis

Introduction

Chronic endometritis is a common disease in women of childbearing age and can cause pelvic inflammatory disease. The cGAS-STING pathway plays an important role in many inflammatory diseases.

Purpose

The aim of this study was to investigate the relationship between the cGAS-STING pathway and endometritis.

Methods

We collected endometrium samples from patients with endometritis to detect changes in the cGAS-STING pathway. In vitro, human endometrial stromal cells (HESC) were stimulated with lipopolysaccharide (LPS), and a mouse STING gene-knockout model was established by CRISPR/cas9 for STING to further explore the mechanism underlying its effects in endometritis. We used Western blotting (WB) and immunohistochemical staining to detect the variations in protein levels and real-time PCR to study the variations in gene expression.

Results

We observed the activation of the cGAS-STING pathway and an increase in the expression of cytokine-encoding genes, including IL-8, IL-6, IL-1β, and IFN-β1, in endometrial tissues of patients with endometritis. Stimulation of HESCs using LPS demonstrated increase in the expression of proteins involved the cGAS-STING pathway and the gene expression of inflammatory cytokines. STING-knockdown experiments demonstrated a decrease in the gene expression levels of inflammatory cytokines. Moreover, we also identified the translocation of IRF3 and STING after LPS stimulation. Regarding mitochondrial function, LPS led to an increase in reactive oxygen species levels and a reduction in mitochondrial membrane potential. However, we observed that the mitochondrial DNA (mtDNA) leaked into the cytoplasm, upregulating the levels of proteins involved in the cGAS-STING pathway upon LPS stimulation. Furthermore, our results showed that LPS induced hyperemia, inflammatory factor production, and expression of Pho-TBK1 in wild-type mice compared with the levels in control mice, and STING gene-knockdown alleviated these effects.

Conclusion

LPS induces mitochondrial dysfunction in endometrial stromal cells, resulting in mtDNA leakage and promoting endometritis by stimulating the cGAS-STING pathway.

Icariin Alleviates Escherichia coli Lipopolysaccharide-Mediated Endometritis in Mice by Inhibiting Inflammation and Oxidative Stress

Icariin (ICA) is a naturally occurring phytochemical agent primarily extracted from Epimedium Brevicornum Maxim (Family Berberidaceae) with a broad spectrum of bioactivities. Endometritis is a uterine disease that causes enormous losses in the dairy industry worldwide. In this study, anti-inflammatory and anti-oxidant properties of ICA were investigated against lipopolysaccharide (LPS)-induced endometritis in mice to investigate possible underlying molecular mechanisms. Sixty heathy female Kunming mice were randomly assigned to four groups (n = 15), namely control, LPS, LPS + ICA, and ICA groups. The endometritis was induced by intrauterine infusion of 50 µL of LPS (1 mg/mL). After 24 h of onset of LPS-induced endometritis, ICA groups were injected thrice by ICA intraperitoneally six hours apart. Histopathological examination, enzyme linked immunosorbent assay (ELISA), real time quantitative polymerase chain reaction (RT-qPCR), western blotting, and immunohistochemistry were used in this study. Histological alterations revealed that ICA markedly mitigated uterine tissue injury caused by LPS. The results showed that the ICA inhibited the production of pro-inflammatory cytokines (IL-1ß, IL-6, and TNF-α) and boosted the production of anti-inflammatory cytokines (IL-10). Additionally, ICA modulated the expression of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase 1 (SOD1), catalase (CAT), and glutathione peroxidase 1 (Gpx1) induced by LPS. The administration of ICA significantly (p < 0.05) improved the mRNA and protein expression of Toll-like receptor (TLR) 4. The western blotting and ELISA finding revealed that the ICA repressed LPS-triggered NF-κB pathway activation. Moreover, ICA improved the antioxidant defense system via activation of the Nrf2 pathway. The results revealed that ICA up-regulated the mRNA and protein expression of Nuclear erythroid-2-related factor (Nrf2), NAD(P)H: quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), and glutamate-cysteine ligase catalytic subunit (GCLC) under LPS exposure. Conclusively, our findings strongly suggested that ICA protects endometritis caused by LPS by suppressing TLR4-associated NF-κB and Nrf2 pathways. Altogether, these innovative findings may pave the way for future studies into the therapeutic application of ICA to protect humans and animals against endometritis.

Nrf2/HO-1 pathway is involved the anti-inflammatory action of intrauterine infusion of platelet-rich plasma against lipopolysaccharides in endometritis

OBJECTIVE(S)

Endometritis is the inflammatory response of the uterine lining which is linked to infertility. Administration of platelet-rich plasma (PRP) represents a well-recommended strategy for the treatment of endometrium-associated infertility. In this study, we set to characterize the role and molecular mechanism of PRP intrauterine infusion in mice with endometritis.

METHODS

A mouse model of endometritis was established using lipopolysaccharide (LPS). Mouse endometrial epithelial cells were obtained in primary culture. PRP-treated cells were assayed for proliferative and apoptotic activities. Moreover, iNOS expression and chemokine and inflammatory factor contents in cells were assessed using RT-qPCR and ELISA. The mice were subjected to PRP intrauterine infusion. The expression of genes related to uterine development was analyzed by qPCR and the ki-67 content and caspase-3 activation in endometrial tissues were examined by immunohistochemistry. Finally, the Nrf2/HO-1 pathway activity in tissues was examined by Western blot.

RESULTS

LPS induced inflammatory cell recruitment and tissue damage in the endometrium of mice, along with significantly increased levels of inflammatory and chemokine factors. PRP significantly enhanced endometrial epithelial cell activity, decreased apoptosis, and reduced inflammatory factor secretion. In addition, PRP intrauterine infusion significantly increased the expression of genes related to uterine development, promoted tissue proliferation, decreased apoptosis, and diminished inflammatory response in endometrial tissues of mice. PRP intrauterine infusion significantly elevated Nrf2/HO-1 pathway activity in endometrial epithelial cells and tissues.

CONCLUSION

PRP intrauterine infusion significantly inhibited endometrial cell injury and alleviated the inflammatory response through activating the Nrf2/HO-1 pathway.

Lamiaceae in Mexican Species, a Great but Scarcely Explored Source of Secondary Metabolites with Potential Pharmacological Effects in Pain Relief

The search for molecules that contribute to the relief of pain is a field of research in constant development. Lamiaceae is one of the most recognized families world-wide for its use in traditional medicine to treat diseases that include pain and inflammation. Mexico can be considered one of the most important centers of diversification, and due to the high endemism of this family, it is crucial for the in situ conservation of this family. Information about the most common genera and species found in this country and their uses in folk medicine are scarcely reported in the literature. After an extensive inspection in bibliographic databases, mainly Sciencedirect, Pubmed and Springer, almost 1200 articles describing aspects of Lamiaceae were found; however, 217 articles were selected because they recognize the Mexican genera and species with antinociceptive and/or anti-inflammatory potential to relieve pain, such as Salvia and Agastache. The bioactive constituents of these genera were mainly terpenes (volatile and non-volatile) and phenolic compounds such as flavonoids (glycosides and aglycone). The aim of this review is to analyze important aspects of Mexican genera of Lamiaceae, scarcely explored as a potential source of secondary metabolites responsible for the analgesic and anti-inflammatory properties of these species. In addition, we point out the possible mechanisms of action involved and the modulatory pathways investigated in different experimental models. As a result of this review, it is important to mention that scarce information has been reported regarding species of this family from Mexican genera. In fact, despite Calosphace being one of the largest subgenera of Salvia in the world, found mainly in Mexico, it has been barely investigated regarding its potential biological activities and recognized bioactive constituents. The scientific evidence regarding the different bioactive constituents found in species of Lamiaceae demonstrates that several species require further investigation in preclinical studies, and of course also in controlled clinical trials evaluating the efficacy and safety of these natural products to support their therapeutic potential in pain relief and/or inflammation, among other health conditions. Since Mexico is one of the most important centers of diversification, and due to the high endemism of species of this family, it is crucial their rescue, in situ conservation, and investigation of their health benefits.

Functionality of apigenin as a potent antioxidant with emphasis on bioavailability, metabolism, action mechanism and in vitro and in vivo studies: A review

Numerous diseases such as cancer, diabetes, cardiovascular, neurodegenerative diseases, etc. are linked with overproduction of reactive oxygen species (ROS) and oxidative stress. Apigenin (5,7,4'-trihydroxyflavone) is a widely distributed flavonoid, responsible for antioxidant potential and chelating redox active metals. Being present as glycosides or polymers, the apigenin degrades to variable amount in the digestive tract; during processing, its activity is also reduced due to high temperature or Fe/Cu addition. Although its metabolism remains elusive, enteric absorption occurs sufficiently to reduce plasma indices of oxidant status. Delayed clearance in plasma and slow liver decomposition enhance its systematic bioavailability. Antioxidant mechanism of apigenin includes: oxidant enzymes inhibition, modulation of redox signaling pathways (NF-kB, Nrf2, MAPK, and P13/Akt), reinforcing enzymatic and nonenzymatic antioxidant, metal chelation, and free radical scavenging. DPPH, ORAC, ABTS, and FRAP are the major in vitro methods for determining the antioxidant potential of apigenin, whereas its protective effects in whole and living cells of animals are examined using in vivo studies. Due to limited information on antioxidant potential of apigenin, its in vitro and in vivo antioxidant effects are, therefore, discussed with action mechanism and interaction with the signaling pathways. This paper concludes that apigenin is a potent antioxidant compound to overcome the difficulties related to oxidative stress and other chronic diseases.

Apigenin exerts chemopreventive effects on lung injury induced by SiO2 nanoparticles through the activation of Nrf2

Apigenin (APG) is a flavonoid widely distributed in fruits, vegetables, and herbs, with comprehensive pharmacological effects. In this paper, we report that APG can elicit a protective effect, which is comparable to those induced by gymnoside II/n-BuOH extracts of Bletilla striata, on SiO₂-induced lung injury in vitro and in vivo. In vitro experiments showed that APG (25 μM) could restore the SiO₂-decreased A549 cell viability and lower the apoptotic rate and the production of intracellular reactive oxygen species (ROS) in A549 cells treated with nm SiO₂. Western blot results showed that APG (25 μM) could increase the level of Nuclear factor E2-related factor 2 (Nrf2) and its downstream proteins. In vivo experiments showed that APG (20 mg/kg) could potently alleviate the SiO₂-elicited lung injury by enhancing the Nrf2 expression and thereby suppressing Bax/Bcl-2 pathway. The present study suggests that APG can significantly alleviate the SiO₂-induced lung injury both in vitro and in vivo through, at least partially, activating Nrf2 expression.

CircRNA circFADS2 is Downregulated in Endometritis and its Overexpression Promotes miR-643 Maturation in Human Endometrial Epithelial Cells to Suppress Cell Apoptosis

CircRNA circFADS2 suppresses LPS-induced inflammation, which plays a critical role in endometritis. Our preliminary sequencing analysis revealed a positive correlation between circFADS2 and miR-643, which also play protective roles in LPS-induced inflammation. Therefore, this study was performed to explore the involvement of circFADS2 in endometritis with a focus on its interaction with miR-643. RT-qPCR was performed to analyze the levels circFADS2, mature miR-643, and premature miR-643 in plasma samples from endometritis patients (n = 66) and healthy controls (n = 66). Pearson's correlation coefficient was applied to analyze correlations between these genes. The effect of circFADS2 on miR-643 maturation was analyzed by measuring miR-643 and premature miR-643 levels in circFADS2-overexpressed human endometrial epithelial cell line HEnEpCs. The role of circFADS2 and miR-643 in HEnEpC apoptosis under LPS treatment was analyzed by cell apoptosis assay. CircFADS2 was downregulated in endometritis and was positively correlated with mature miR-643, but not premature miR-643. CircFADS2 overexpression in HEnEpCs increased the level of mature miR-643 but not premature miR-643. Cell apoptosis analysis showed that circFADS2 and miR-643 overexpression protected HEnEpCs from LPS-induced cell apoptosis, and miR-643 inhibition reduced the effect of circFADS2 overexpression. CircFADS2 is downregulated in endometritis, and it overexpression promotes miR-643 maturation in HEnEpCs to suppress cell apoptosis.

Chlorogenic acid ameliorates mice clinical endometritis by activating Keap1/Nrf2 and inhibiting NFκB signalling pathway

OBJECTIVES

Clinical endometritis is a common reproductive disorder in mammals that seriously endangers animal health and causes economic losses worldwide. This study aims to use lipopolysaccharide and Trueperella pyogenes exotoxin as modelling reagents (LC) to perfuse the mouse uterus in order to establish a model of clinical endometritis and to investigate the anti-inflammatory and antioxidant effects of chlorogenic acid (CGA).

METHODS

In this study, five LC uterine perfusions were selected to model clinical endometritis. The anti-inflammatory and antioxidant effects of CGA were clarified. Through HE staining, proinflammatory cytokines, blood testing, NFκB and Keap1/Nrf2 signalling pathways and other index changes to explore the protection mechanism of CGA.

KEY FINDINGS

After CGA treatment, the appearance, inflammatory damage and blood indicators of the mouse uterus returned to normal. Simultaneously, CGA could inhibit the activation of NFκB and reduce the release of inflammatory cytokines; CGA could also activate Keap1/Nrf2, promote the dissociation of Keap1 and Nrf2 and significantly increase the expression of the downstream genes HO-1 and NQO1.

CONCLUSIONS

The above results together explain that five LC uterine perfusions can be used to establish a mouse model of clinical endometritis. CGA can treat clinical endometritis by activating Keap1/Nrf2 and inhibiting the NFκB signalling pathway.

Baicalin attenuates endometritis in a rabbit model induced by infection with Escherichia coli and Staphylococcus aureus via NF-κB and JNK signaling pathways

In this study, a rabbit endometritis model was developed to study cow endometritis. In addition, the protective effects of baicalin (a flavonoid) against endometritis were investigated. Clinical symptoms, differential leukocyte counting, uterine secretion smear microscopy and chemical examination, urine testing, and signs of necropsy showed abnormal changes and inflammatory responses in the uterus of rabbits. Histopathological results revealed visible inflammatory exudates and blood spots between intercellular spaces which confirmed that the rabbit endometritis model was successfully developed. Most importantly, these inflammatory signs were partially attenuated with baicalin treatment. The data revealed that the increased body temperature and leukocyte cells, pus, and the detachment of epithelial cells were alleviated with baicalin administration in a dose-dependent manner. Histopathological tissue changes such as inflammatory cells infiltrates, hyperemia, hemorrhages, and shedding of epithelial cells were partially attenuated with baicalin treatment. In addition, the mRNA expression of inflammation-related genes (iNOS, IL-1β, TNF-α, IL-10, IL-4, and IL-6) was significantly altered in RAW264.7 cells after LPS treatment. Further, the phosphorylated protein expression of JNK, p65, and IκBα were significantly reduced with LPS treatment. Intriguingly, baicalin pretreatment reversed the alteration in mRNA expression of inflammation-related genes and significantly reduced the phosphorylation of JNK, p65, and IκBα. In summary, our results suggest that baicalin has protective effects on bacterial-induced endometritis in rabbits that involve the suppression of NF-κB and JNK signaling pathways and pro-inflammatory cytokines.

Therapeutic Potential of Flavonoids in Pain and Inflammation: Mechanisms of Action, Pre-Clinical and Clinical Data, and Pharmaceutical Development

Pathological pain can be initiated after inflammation and/or peripheral nerve injury. It is a consequence of the pathological functioning of the nervous system rather than only a symptom. In fact, pain is a significant social, health, and economic burden worldwide. Flavonoids are plant derivative compounds easily found in several fruits and vegetables and consumed in the daily food intake. Flavonoids vary in terms of classes, and while structurally unique, they share a basic structure formed by three rings, known as the flavan nucleus. Structural differences can be found in the pattern of substitution in one of these rings. The hydroxyl group (-OH) position in one of the rings determines the mechanisms of action of the flavonoids and reveals a complex multifunctional activity. Flavonoids have been widely used for their antioxidant, analgesic, and anti-inflammatory effects along with safe preclinical and clinical profiles. In this review, we discuss the preclinical and clinical evidence on the analgesic and anti-inflammatory proprieties of flavonoids. We also focus on how the development of formulations containing flavonoids, along with the understanding of their structure-activity relationship, can be harnessed to identify novel flavonoid-based therapies to treat pathological pain and inflammation.

Chronic pelvic pain syndrome: Highlighting medicinal plants toward biomolecules discovery for upcoming drugs formulation

Chronic pelvic pain syndrome (CPPS) can be triggered by a various types of gynecological, gastrointestinal, urological, and musculoskeletal disorders. Recently, the role of the central nervous system has proven to be an integral part on the development of any chronic pain syndrome, including CPPS. However, owing to the complex and heterogeneous etiology and pathophysiology of CPPS, the establishment of effective therapeutic interventions remains challenging for both physicians and patients. Nonetheless, recent studies have pointed that medicinal plants and their secondary metabolites can be effectively used in CPPS therapy, besides contributing to restore the patients' quality of life and potentiate the conventional CPPS management. In this sense, this review aims to provide a careful overview on the biomedical data for the use of medicinal plants use and their secondary metabolites on CPPS management.

Apigenin exhibits anti-inflammatory effects in LPS-stimulated BV2 microglia through activating GSK3β/Nrf2 signaling pathway

Objective: Apigenin is a natural flavonoid compound extracted from Matricaria chamomilla. We evaluated the anti-inflammatory effects of apigenin in this study using the Lipopolysaccharide (LPS)-stimulated BV2 microglia.Methods: BV2 cells were treated with apigenin for 1 h and then treated with LPS. The inflammatory cytokine productions were tested by qRT-PCR and ELISA. The expression of GSK3β, Nrf2, and NF-κB signaling pathways were measured by western blot analysis.Results: Apigenin significantly attenuated LPS-induced TNF-α, IL-1β, and IL-6 production. Apigenin suppressed LPS-induced NF-κB activation. Furthermore, GSK3β, Nrf2, and HO-1 were concentration-dependently increased by apigenin. The suppression of apigenin on LPS-induced inflammatory response and NF-κB activation were prevented when Nrf2 was knocked out or by GSK3β inhibitor.Conclusions: Collectively, apigenin suppressed LPS-induced microglia activation via activating GSK3β/Nrf2 signaling pathway.

TREM-1 deficiency attenuates the inflammatory responses in LPS-induced murine endometritis

Endometritis, which is usually caused by bacterial infection, is characterized by high levels of pro-inflammatory cytokines and a high infertility rate. Triggering receptor expressed on myeloid cells-1 (TREM-1) has been recognized as a potent amplifier of inflammatory reactions. Studies have demonstrated reduced inflammatory responses and mortality rates of animals with bacterial infection due to the blocking of TREM-1 expression. However, whether TREM-1 deficiency could alleviate the inflammatory reaction in bacterial endometritis is still unclear. Here, TREM-1 knock-out (Trem-1-/- ) mice were used to inhibit TREM-1 signalling to evaluate its role in inflammatory reactions after a highly pathogenic LPS infection in mice uteri. The results demonstrated that TREM-1 deficiency attenuated the inflammation in mice uteri; markedly reduced the number of polymorphonuclear neutrophils; and suppressed interleukin-1β (IL-1β), IL-6, and tumour necrosis factor-α (TNF-α) concentrations in serum as well as their production in inflamed uteri after LPS stimulation. Our results illustrate an anticipated pathogenic impact of TREM-1 on endometritis during LPS infection and indicate that blocking of TREM-1 in LPS-induced endometritis holds considerable promise for blunting excessive inflammation.

Protective Effects of Astragaloside IV against LPS-Induced Endometritis in Mice through Inhibiting Activation of the NF-κB, p38 and JNK Signaling Pathways

Endometritis, inflammation of the endometrium, is a common reproductive obstacle disease that can lead to infertility in female animals. Astragaloside IV (AS IV), one of the major and active components of the Astragalus membranaceus (Fisch.) Bunge, is known for its anti-inflammatory effects. In the present study, the effects and mechanisms of AS IV on lipopolysaccharide (LPS)-induced endometritis were investigated using a mouse model. Female mice were prepared with AS IV (0.01 mg/g) by gavage for six days before being stimulated with LPS. The results showed that the histopathological changes, levels of inflammatory cytokines (IL-1β and TNF-α), concentration of NO, and myeloperoxidase (MPO) activity in LPS-induced uteri were attenuated significantly by pretreatment with AS IV. Furthermore, LPS-induced activations of NF-κB, p38, and JNK signal pathways were suppressed by pretreatment with AS IV. In conclusion, the data provided new evidence that AS IV effectively attenuates LPS-induced endometritis through inhibition of TLR4-mediated NF-κB, p38, and JNK signaling pathways, implying that AS IV might become a promising potential anti-inflammatory agent for endometritis and other inflammatory diseases.