Paeonol attenuates ligation-induced periodontitis in rats by inhibiting osteoclastogenesis via regulating Nrf2/NF-κB/NFATc1 signaling pathway

Quercetin, Main Active Ingredient of Moutan Cortex, Alleviates Chronic Orofacial Pain via Block of Voltage-Gated Sodium Channel

BACKGROUND

Chronic orofacial pain (COP) therapy is challenging, as current medical treatments are extremely lacking. Moutan Cortex (MC) is a traditional Chinese medicine herb widely used for chronic inflammatory diseases. However, the mechanism behind MC in COP therapy has not been well-established. The purpose of this study was to identify the active ingredients of MC and their specific underlying mechanisms in COP treatment.

METHODS

In this study, the main active ingredients and compound-target network of MC in COP therapy were identified through network pharmacology and bioinformatics analysis. Adult male Sprague-Dawley rats received oral mucosa lipopolysaccharide (LPS) injection to induce COP. Pain behaviors were evaluated by orofacial mechanical nociceptive assessment after intraganglionar injection. In vitro inflammatory cytokines in LPS-pretreated human periodontal ligament stem cells (hPDLSCs) and rat primary cultural trigeminal ganglion (TG) neurons were quantified by real-time quantitative polymerase chain reaction (RT-qPCR). Schrödinger software was used to verify the molecular docking of quercetin and critical targets. Whole-cell recording electrophysiology was used to evaluate the effect of quercetin on voltage-gated sodium (Na v ) channel in rat TG neurons.

RESULTS

The assembled compound-target network consisted of 4 compounds and 46 targets. As 1 of the active components of MC correlated with most related targets, quercetin alleviated mechanical allodynia in LPS-induced rat model of COP (mechanical allodynia threshold median [interquartile range (IQR) 0.5 hours after drug administration: vehicle 1.3 [0.6-2.0] g vs quercetin 7.0 [6.0-8.5] g, P = .002). Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that immune response and membrane functions play essential roles in MC-COP therapy. Five of the related targets were identified as core targets by protein-protein interaction analysis. Quercetin exerted an analgesic effect, possibly through blocking Na v channel in TG sensory neurons (peak current density median [IQR]: LPS -850.2 [-983.6 to -660.7] mV vs LPS + quercetin -589.6 [-711.0 to -147.8] mV, P = .006) while downregulating the expression level of proinflammatory cytokines-FOS (normalized messenger RNA [mRNA] level mean ± standard error of mean [SEM]: LPS [2. 22 ± 0.33] vs LPS + quercetin [1. 33 ± 0.14], P = .034) and TNF-α (normalized mRNA level mean ± SEM: LPS [8. 93 ± 0.78] vs LPS + quercetin [3. 77 ± 0.49], P < .0001).

CONCLUSIONS

Identifying Na v as the molecular target of quercetin clarifies the analgesic mechanism of MC, and provides ideas for the development of novel selective and efficient chronic pain relievers.

Global trends in research on aging associated with periodontitis from 2002 to 2023: a bibliometric analysis

Background

Aging has been implicated in many chronic inflammatory diseases, including periodontitis. Periodontitis is an inflammatory disease caused by long-term irritation of the periodontal tissues by the plaque biofilm on the surface of the teeth. However, only a few bibliometric analyses have systematically studied this field to date. This work sought to visualize research hot spots and trends in aging associated with periodontitis from 2002 to 2023 through bibliometric approaches.

Methods

Graphpad prism v8.0.2 was used to analyse and plot annual papers, national publication trends and national publication heat maps. In addition, CtieSpace (6.1.6R (64-bit) Advanced Edition) and VOSviewer (version 1.6.18) were used to analyse these data and visualize the scientific knowledge graph.

Results

The number of documents related to aging associated with periodontitis has steadily increased over 21 years. With six of the top ten institutions in terms of publications coming from the US, the US is a major driver of research in this area. journal of periodontology is the most published journal in the field. Tonetti MS is the most prolific authors and co-cited authors in the field. Journal of Periodontology and Journal of Clinical Periodontology are the most popular journals in the field with the largest literature. Periodontitis, Alzheimer's disease, and peri-implantitis are current hot topics and trends in the field. Inflammation, biomarkers, oxidative stress cytokines are current research hotspots in this field.

Conclusion

Our research found that global publications regarding research on aging associated with periodontitis increased dramatically and were expected to continue increasing. Inflammation and aging, and the relationship between periodontitis and systemic diseases, are topics worthy of attention.

Redox signaling and antioxidant defense in osteoclasts

Bone remodeling is essential for the repair and replacement of damaged or aging bones. Continuous remodeling is necessary to prevent the accumulation of bone damage and to maintain bone strength and calcium balance. As bones age, the coupling mechanism between bone formation and absorption becomes dysregulated, and bone loss becomes dominant. Bone development and repair rely on interaction and communication between osteoclasts and surrounding cells. Osteoclasts are specialized cells that are accountable for bone resorption and degradation, and any abnormalities in their activity can result in notable alterations in bone structure and worsen disease symptoms. Recent findings from transgenic mouse models and bone analysis have greatly enhanced our understanding of the origin, differentiation pathway, and activation stages of osteoclasts. In this review, we explore osteoclasts and discuss the cellular and molecular events that drive their generation, focusing on intracellular oxidative and antioxidant signaling. This knowledge can help develop targeted therapies for diseases associated with osteoclast activation.

Garcinone C attenuates RANKL-induced osteoclast differentiation and oxidative stress by activating Nrf2/HO-1 and inhibiting the NF-kB signaling pathway

Osteoporosis is the result of osteoclast formation exceeding osteoblast production, and current osteoporosis treatments targeting excessive osteoclast bone resorption have serious adverse effects. There is a need to fully understand the mechanisms of osteoclast-mediated bone resorption, identify new drug targets, and find better drugs to treat osteoporosis. Gar C (Gar C) is a major naturally occurring phytochemical isolated from mangosteen, and is a derivative of the naturally occurring phenolic antioxidant lutein. We used an OP mouse model established by ovariectomy (OVX). We found that treatment with Gar C significantly increased bone mineral density and significantly decreased the expression of TRAP, NFATC1 and CTSK relative to untreated OP mice. We found that Garcinone C could disrupt osteoclast activation and resorption functions by inhibiting RANKL-induced osteoclast differentiation as well as inhibiting the formation of multinucleated osteoclasts. Immunoblotting showed that Gar C downregulated the expression of osteoclast-related proteins. In addition, Gar C significantly inhibited RANKL-induced ROS production and affected NF-κB activity by inhibiting phosphorylation Formylation of P65 and phosphorylation and degradation of ikba. These data suggest that Gar C significantly reduced OVX-induced osteoporosis by inhibiting osteoclastogenesis and oxidative stress in bone tissue. Mechanistically, this effect was associated with inhibition of the ROS-mediated NF-κB pathway.

Plant molecules reinforce bone repair: Novel insights into phenol-modified bone tissue engineering scaffolds for the treatment of bone defects

Bone defects have become a major cause of disability and death. To overcome the limitations of natural bone implants, including donor shortages and immune rejection risks, bone tissue engineering (BTE) scaffolds have emerged as a promising therapy for bone defects. Despite possessing good biocompatibility, these metal, ceramic and polymer-based scaffolds are still challenged by the harsh conditions in bone defect sites. ROS accumulation, bacterial infection, excessive inflammation, compromised blood supply deficiency and tumor recurrence negatively impact bone tissue cells (BTCs) and hinder the osteointegration of BTE scaffolds. Phenolic compounds, derived from plants and fruits, have gained growing application in treating inflammatory, infectious and aging-related diseases due to their antioxidant ability conferred by phenolic hydroxyl groups. The prevalent interactions between phenols and functional groups also facilitate their utilization in fabricating scaffolds. Consequently, phenols are increasingly incorporated into BTE scaffolds to boost therapeutic efficacy in bone defect. This review demonstrated the effects of phenols on BTCs and bone defect microenvironment, summarized the intrinsic mechanisms, presented the advances in phenol-modified BTE scaffolds and analyzed their potential risks in practical applications. Overall, phenol-modified BTE scaffolds hold great potential for repairing bone defects, offering novel patterns for BTE scaffold construction and advancing traumatological medicine.

Anti-Inflammatory Activity of APPA (Apocynin and Paeonol) in Human Articular Chondrocytes

Osteoarthritis (OA) is a chronic joint disease leading to cartilage loss and reduction in the joint space which results in pain. The current pharmacological treatment of OA is inadequate and pharmacological interventions focus on symptom management. APPA, a combination of apocynin (AP) and paeonol (PA), is a potential drug for treating OA. The aim of this study was to analyze the effects of APPA on the modulation of the inflammatory response in chondrocytes. Samples were incubated with IL-1β and APPA, and their responses to proinflammatory cytokines, catabolic mediators and redox responses were then measured. The effect of APPA on mitogenesis was also evaluated. Results show that APPA attenuated the expression of IL-8, TNF-α, MMP-3, MMP-13, SOD-2 and iNOS, resulting in the protection of human articular cartilage. APPA decreased PGC-1α gene expression induced by IL-1β. APPA did not modulate the gene expression of Mfn2, Sirt-1 or Sirt-3. The overall findings indicate that APPA may be an effective treatment for OA by targeting several of the pathways involved in OA pathogenesis.

Identification of hub cuproptosis related genes and immune cell infiltration characteristics in periodontitis

Introduction

Periodontitis is an inflammatory disease and its molecular mechanisms is not clear. A recently discovered cell death pathway called cuproptosis, may related to the disease.

Methods

The datasets GSE10334 of human periodontitis and control were retrieved from the Gene Expression Omnibus database (GEO) for analysis.Following the use of two machine learning algorithms, least absolute shrinkage and selection operator (LASSO) and support vector machine-recursive feature removal (SVM-RFE) were used to find CRG-based signature. Then the Receiver operating characteristic (ROC) curves was used to evaluate the gene signature's discriminatory ability. The CIBERSORT deconvolution algorithm was used to study the link between hub genes and distinct types of immune cells. Next, the association of the CRGs with immune cells in periodontitis and relevant clusters of cuproptosis were found. The link between various clusters was ascertained by the GSVA and CIBERSORT deconvolution algorithm. Finally, An external dataset (GSE16134) was used to confirm the diagnosis capacity of the identified biomarkers. In addition, clinical samples were examined using qRT-PCR and immunohistochemistry to verifiy the expression of genes related to cuprotosis in periodontitis and the signature may better predict the periodontitis.

Results

15 periodontitis-related DE-CRGs were found,then 11-CRG-based signature was found by using of LASSO and SVM-RFE. ROC curves also supported the value of signature. CIBERSORT results of immune cell signature in periodontitis showed that signature genes is a crucial component of the immune response.The relevant clusters of cuproptosis found that the NFE2L2, SLC31A1, FDX1,LIAS, DLD, DLAT, and DBT showed a highest expression levels in Cluster2 ,while the NLRP3, MTF1, and DLST displayed the lowest level in Cluster 2 but the highest level in Cluster1. The GSVA results also showed that the 11 cuproptosis diagnostic gene may regulate the periodontitis by affecting immune cells. The external dataset (GSE16134) confirm the diagnosis capacity of the identified biomarkers, and clinical samples examined by qRT-PCR and immunohistochemistry also verified that these cuprotosis related signiture genes in periodontitis may better predict the periodontitis.

Conclusion

These findings have important implications for the cuproptosis and periodontitis, and highlight further research is needed to better understand the mechanisms underlying this relationship between the cuproptosis and periodontitis.

Protective effect of Nrf2 in periodontitis - A preclinical systematic review and meta-analysis

OBJECTIVE

Periodontitis is an inflammatory disease, while Nuclear factor erythroid-2 related factor 2 (Nrf2) acts a significant part in antioxidant, anti-inflammatory and immune response. However, the evidence in preclinical studies to certify Nrf2 can slow down the progression of periodontitis or facilitate its recovery is not enough. The present report aims to investigate the functional implications of Nrf2 in animal periodontitis models by evaluating the changes of Nrf2 levels and analyzing the clinical benefits of Nrf2 activation in the same models.

DESIGN

We searched PubMed, Web of Science, EBSCO, CNKI, VIP, Wan Fang databases. The random-effects model was used to evaluate the mean differences (MD) and 95 % confidence intervals (95%CI) when the units of measurements of outcome indicators were the same, in contrast, the standardized mean differences (SMD) and 95%CI were evaluated while the units were different.

RESULTS

8 studies were included for quantitative synthesis. Compared with healthy groups, the expression of Nrf2 was markedly lower in periodontitis groups (SMD: -3.69; 95%CI: -6.25, -1.12). After administration of kinds of Nrf2-activators, a significant increase in Nrf2 levels (SMD: 2.01; 95%CI: 1.27, 2.76) was accompanied by a decrease in distance between cementoenamel junction and alveolar bone crest (CEJ-ABC) (SMD: -2.14; 95%CI: -3.29, -0.99) and an improvement of bone volume/tissue volume (BV/TV) (SMD:17.51; 95%CI: 16.24, 18.77) was evaluated compared with periodontitis groups.

CONCLUSIONS

Nrf2 has a certain protective effect on periodontitis, however, the specific role Nrf2 plays in the development and severity of periodontitis remains to be demonstrated. PROSPERO registration number: CRD42022328008.

Paeonol ameliorates diabetic erectile dysfunction by inhibiting HMGB1/RAGE/NF-kB pathway

BACKGROUND

The management of diabetes mellitus-induced erectile dysfunction (DMED) is progressively becoming tricky due to the surge in the number of patients and the poor efficiency of phosphodiesterase type 5 inhibitors in DMED. Paeonol (Pae), as a traditional Chinese medicine, has been more and more widely used in the treatment of diabetic complications. However, whether Pae could be a potential therapeutic drug of DMED needs to be further evaluated.

OBJECTIVES

To investigate the pharmacological effect and possible mechanism of Pae in the treatment of DMED.

METHODS

Intraperitoneal streptozotocin injection and an apomorphine test were used to construct the model of DMED. Seventeen DMED rats were divided into two groups: DMED group (n = 8) and DMED+Pae group (Pae; 100 mg/kg/d; oral administration; n = 9). In addition, there were still 10 normal age-matched male rats as control group. Four weeks later, the cavernous nerve electric stimulation was carried out to measure the erectile response. Moreover, the corpus cavernosum smooth muscle cells (CCSMCs) were primarily isolated and exposed to high glucose (HG) stimulation, Pae treatment and glycyrrhizin (GL; the selective inhibitor of HMGB1). After an incubation for 1 week, the CCSMCs were harvested for detection.

RESULTS

The impairment of erectile function was observed in DMED rats compared with control samples, accompanied by the upregulation of HMGB1/RAGE/NF-κB Pathway. The lower nitric oxide and cGMP level and the higher level of inflammation, fibrosis, and apoptosis were also observed in DMED rats. It showed contrast that Pae treatment could improve the erectile function, as well as histologic alteration and related molecular changes. In addition, Pae could downregulate the HMGB1/RAGE/NF-κB pathway to regulate the apoptosis and inflammation levels of CCSMCs in high-glucose conditions, which is similar to the results of GL treatment.

CONCLUSION

Pae alleviated ED in DMED rats, likely by inhibiting HMGB1/RAGE/NF-κB Pathway, inflammatory, apoptosis, and fibrotic activity, and moderating endothelial dysfunction. Our study provide evidence for a potential new therapy for DMED.

LIPUS as a potential strategy for periodontitis treatment: A review of the mechanisms

Periodontitis is a chronic inflammatory condition triggered by oral bacteria. A sustained inflammatory state in periodontitis could eventually destroy the alveolar bone. The key objective of periodontal therapy is to terminate the inflammatory process and reconstruct the periodontal tissues. The traditional Guided tissue regeneration (GTR) procedure has unstable results due to multiple factors such as the inflammatory environment, the immune response caused by the implant, and the operator's technique. Low-intensity pulsed ultrasound (LIPUS), as acoustic energy, transmits the mechanical signals to the target tissue to provide non-invasive physical stimulation. LIPUS has positive effects in promoting bone regeneration, soft-tissue regeneration, inflammation inhibition, and neuromodulation. LIPUS can maintain and regenerate alveolar bone during an inflammatory state by suppressing the expression of inflammatory factors. LIPUS also affects the cellular behavior of periodontal ligament cells (PDLCs), thereby protecting the regenerative potential of bone tissue in an inflammatory state. However, the underlying mechanisms of the LIPUS therapy are still yet to be summarized. The goal of this review is to outline the potential cellular and molecular mechanisms of periodontitis-related LIPUS therapy, as well as to explain how LIPUS manages to transmit mechanical stimulation into the signaling pathway to achieve inflammatory control and periodontal bone regeneration.

The role of Nrf2 in periodontal disease by regulating lipid peroxidation, inflammation and apoptosis

Nuclear factor E2-related factor 2(Nrf2) is a transcription factor that mainly regulates oxidative stress in the body. It initiates the expression of several downstream antioxidants, anti-inflammatory proteins and detoxification enzymes through the Kelch-like ECH-associating protein 1 (Keap1) -nuclear factor E2-related factor 2(Nrf2) -antioxidant response element (ARE) signaling pathway. Its anti-apoptosis, anti-oxidative stress and anti-inflammatory effects have gradually become the focus of periodontal disease research in recent years. In this paper, the structure and function of Nrf2 pathway and its mechanism of action in the treatment of periodontitis in recent years were analyzed and summarized, so as to further clarify the relationship between Nrf2 pathway and oxidative stress in the occurrence and development of periodontitis, and to provide ideas for the development of new treatment drugs targeting Nrf2 pathway.

Codon Usage and Context Analysis of Genes Modulated during SARS-CoV-2 Infection and Dental Inflammation

The overexpression of SARS-CoV-2 primary receptors and co-receptors (ACE2, TMPRSS2, FURIN, and CD147) enhance the likeliness of SARS-CoV-2 infection. The genes for same receptors are overexpressed in the periodontal tissues of periodontitis patients. On the other hand, BMAL1 is recognized to play a crucial role in regulating pulmonary inflammation and enhancing susceptibility to viral infection. Silenced BMAL1 disrupts circadian transcriptional regulations, enhances vulnerability to SARS-CoV-2 infections, and may trigger the further production of TNF-α and other pro-inflammatory cytokines that propagate the cytokine storm and exacerbate periodontal inflammation. Therefore ACE2, TMPRSS2, FURIN, CD147, and BMAL1 are the crossroads between SARS-CoV-2 and Periodontitis genes. The enhanced expression of ACE2, TMPRSS2, FURIN, and CD147 and the diminished expression of BMAL1 may be a strategy to check both ailments simultaneously. In gene manipulation techniques, oligos are introduced, which contain all the necessary information to manipulate gene expression. The data are derived from the studies on genes' molecular patterns, including nucleotide composition, dinucleotide patterns, relative synonymous codon usage, codon usage bias, codon context, and rare and abundant codons. Such information may be used to manipulate the overexpression and underexpression of the genes at the time of SARS-CoV-2 infection and periodontitis to mitigate both ailments simultaneously; it can be explored to uncover possible future treatments.

Exploring Nrf2 as a therapeutic target in testicular dysfunction

Testicular dysfunction, a major contributory factor to infertility, has received a lot of attention over the recent years. Several studies have linked abnormal sperm function and morphology with an enhanced generation of reactive oxygen species (ROS) and oxidative stress. The nuclear factor erythroid-derived 2 (Nrf2) is a transcriptional response to cellular stresses (intrinsic or extrinsic) that regulates the oxidative status, mitochondrial dysfunction, inflammation, and proteostasis. In this review, the therapeutic role of Nrf2 was explored. To do so, scientific data were retrieved from databases such as Elsevier, Wiley, Web of Science, Springer, PubMed, Taylor and Francis, and Google Scholar using search terms such as "Nrf2" and "testis," "sperm," "testicular function," and "testosterone." It has been noted that Nrf2 influences the physiology and pathology of testicular dysfunction, especially in the spermatogenic process, by regulating cellular resistance to oxidative stress, inflammation, and environmental toxicants. However, numerous compounds serve as activators and inhibitors of testicular Nrf2. Nrf2 activators might play a therapeutic role in the prevention and treatment of testicular dysfunction, while molecules that inhibit Nrf2 might induce dysfunction in testis components. Nrf2 activators protect cells against oxidative damage and activate Nrf2/KEAP1 signaling which promotes its movement to the nucleus, and increased Nrf2 function and expression, along with their downstream antioxidant gene. Nrf2 inhibitors facilitate oxidative stress via interfering with the Nrf2 signal pathway. The Nrf2 activation could serve as a promising therapeutic target for testicular dysfunction. This review explored the effect of Nrf2 on testicular function while highlighting potential activators and inhibitors of Nrf2.

Paeonol protects against acute pancreatitis by Nrf2 and NF-κB pathways in mice

OBJECTIVES

Paeonol (PAE) is an active ingredient with anti-inflammatory and antioxidant properties. This study was designed to investigate the effect of PAE on acute pancreatitis (AP).

METHODS

AP was induced by the intraperitoneal injection of 20% l-arginine (4 g/kg) for 6 h. Mice were pretreated with PAE (25, 50 or 100 mg/kg) intragastrically for 5 days. The histological damage and alterations of biochemical indicators, inflammatory cytokines and oxidative stress factors in AP mice were detected. The Nrf2 and NF-κB pathways were examined to illustrate the potential mechanism.

KEY FINDINGS

In AP model, we found that PAE attenuated histological injury of pancreatic tissues, reduced the serum levels of α-amylase and increased Ca2+ contents in a dose-dependent manner. The white blood cell content, and IL-1β, IL-6 and TNF-α levels in the serum of AP mice were reduced by PAE. Furthermore, PAE caused a reduction of MPO and MDA levels, accompanied by an increase in SOD activity in the pancreas of AP mice. We also demonstrated that the alterations of Nrf2 and NF-κB pathways in AP mice were reversed by PAE.

CONCLUSIONS

PAE attenuates inflammation and oxidative stress in the development of AP by the regulation of Nrf2 and NF-κB pathways.

Protective effects of paeonol against lipopolysaccharide-induced liver oxidative stress and inflammation in gibel carp (Carassius auratus gibelio)

Paeonol (2'-hydroxy-4'-methoxyacetophenone) is a phenol that exhibits antioxidant and anti-inflammatory capabilities. In this study, the underlying mechanism of paeonol against LPS-induced oxidative stress and inflammatory responses in gibel carp was investigated. Three hundred healthy gibel carp were divided into five groups (n = 9), intraperitoneally injected with LPS and thereafter treated with paeonol (16 mg/kg and 64 mg/kg). Fish were anesthetized with MS-222 (100 mg/L), and samples were collected at 72 h to investigate plasma biochemical indexes, liver histopathology, antioxidant enzymatic activity, and TLR receptor-related gene expression. Fish injected with LPS (20 mg/kg) exhibited significantly increased plasma aminotransferase (ALT), aminotransferase (AST), lactate dehydrogenase (LDH), glucose (GLU), diamine oxidase (DAO), and alkaline phosphatase (ALP) levels (P < 0.05). In addition, LPS challenge significantly enhanced myeloperoxidase (MPO) and malondialdehyde (MDA) contents, whereas those of catalase (CAT) and glutathione peroxidase (GSH-Px) decreased (P < 0.05). However, treatment with paeonol attenuated these LPS-induced changes (P < 0.05). The mRNA expression of TLR4, TIRAP, MyD88, TRAF6, NF-κB, TNF-α, IL-1β, and IL-8, which were activated by LPS challenge (P < 0.05), were downregulated by paeonol. Additionally, histopathological examination demonstrated that paeonol alleviates LPS-induced hepatic tissue lesions in fish. Taken together, the results suggest that paeonol mitigates LPS-induced liver oxidative stress and inflammation in gibel carp.

Paeonol regulates NLRP3 inflammasomes and pyroptosis to alleviate spinal cord injury of rat

Background

Spinal cord injury (SCI) is a life-threatening traumatic disorder. Paeonol has been confirmed to be involved in a variety of diseases. The purpose of this study is to investigate the role of paeonol on SCI progression.

Methods

Sprague Dawley (SD) rat was used for the establishment of SCI model to explore the anti-inflammation, anti-oxidation, and neuroprotective effects of paeonol (60 mg/kg) on SCI in vivo. For in vitro study, mouse primary microglial cells (BV-2) were induced by lipopolysaccharide (LPS)/adenosine triphosphate (ATP) treatment. The effect of paeonol on the polarization of LPS/ATP-induced BV-2 cells was determined by detection the expression inducible nitric oxide synthase (iNOS), tumour necrosis factor alpha (TNF-α), arginase-1 (Arg-1), and interleukin (IL)-10 using qRT-PCR. ELISA was used to assess the levels of IL-1β, IL-18, TNF-α, malondialdehyde (MDA), and glutathione (GSH). Western blotting was conducted to determine the levels of NLRP3 inflammasomes and TLR4/MyD88/NF-κB (p65) pathway proteins.

Results

Paeonol promoted the recovery of locomotion function and spinal cord structure, and decreased spinal cord water content in rats following SCI. Meanwhile, paeonol reduced the levels of apoptosis-associated speck-like protein (ASC), NLRP3, active caspase 1 and N-gasdermin D (N-GSDMD), repressed the contents of IL-1β, IL-18, TNF-α and MDA, and elevated GSH level. In vitro, paeonol exerted similarly inhibiting effects on pyroptosis and inflammation. Meanwhile, paeonol promoted BV-2 cells M2 polarization. In addition, paeonol also inactivated the expression of TLR4/MyD88/NF-κB (p65) pathway.

Conclusion

Paeonol may regulate NLRP3 inflammasomes and pyroptosis to alleviate SCI, pointing out the potential for treating SCI in clinic.

Effect of Yang He Decoction on Treatment of Bone Tuberculosis via Phosphoinositide 3-Kinases/Protein Kinase B and Mitogen-Activated Protein Kinase Signaling Pathways

Yang He Decoction (YHD), a classical Chinese medicine prescription, is used to treat bone and joint diseases. However, there are few mechanism studies for YHD on the use of YHD to treat bone tuberculosis (BT) and the corresponding mechanism of action of YHD. In the present study, the chemical ingredients of YHD and targets of the ingredients were revealed by a network pharmacology method, and an ingredient–target–disease network was visualized and analyzed. Then, gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis were carried out. In addition, molecular docking was performed to clarify the binding of the key active ingredients of YHD to the key targets. Further, an in vitro model of Mycobacterium tuberculosis-induced BT was established, and a mechanism for the inhibitory effect of YHD on the differentiation of RAW 264.7 cells into osteoclasts was investigated. A total of 138 active ingredients in YHD and 50 targets between YHD ingredients and BT were identified. The phosphatidylinositol 3-kinase–protein kinase B (PI3K–Akt) and mitogen-activated protein kinase (MAPK) signaling pathways were the key pathways involved in the anti-BT effect of YHD. Moreover, the in vitro results showed that YHD inhibited the differentiation of RAW 264.7 cells into osteoclasts. YHD decreased the levels of tumor necrosis factor-α and interleukin-1β, increased the levels of superoxide dismutase and glutathione peroxide, and decreased the level of malondialdehyde. Further, YHD inhibited the protein and messenger RNA expression of PI3K/Akt, p38 MAPK, and c-Jun N-terminal kinase. These findings show that YHD is a promising anti-BT agent that suppresses the PI3K/Akt and MAPK signaling pathways to inhibit the differentiation of RAW 264.7 cells into osteoclasts and ameliorate inflammation and oxidative stress.

Cerium oxide nanozyme attenuates periodontal bone destruction by inhibiting the ROS-NFκB pathway

Periodontitis, an inflammatory disease of oxidative stress, occurs due to excess reactive oxygen species (ROS) contributing to cell and tissue damage which in turn leads to alveolar bone resorption as well as the destruction of other periodontal support tissues. With significant recent advances in nanomaterials, we considered a unique type of nanomaterials possessing enzyme-like characteristics (called nanozymes) for potential future clinical applications, especially in light of the increasing number of studies evaluating nanozymes in the setting of inflammatory diseases. Here, we introduced a therapeutic approach for the management of periodontitis utilizing an injection of cerium oxide nanoparticles (CeO₂ NPs) in situ. In this study, our synthesized CeO₂ NPs could act as ROS scavengers in the inflammatory microenvironment with ideal outcomes. In vitro and in vivo experiments provide strong evidence on the roles of CeO₂ NPs in scavenging multiple ROS and suppressing ROS-induced inflammation reactions stimulated by lipopolysaccharides. Moreover, CeO₂ NPs could inhibit the MAPK-NFκB signalling pathway to suppress inflammatory factors. In addition, the results from a rat periodontitis model demonstrate that CeO₂ NPs could exhibit a remarkable capacity to attenuate alveolar bone resorption, decrease the osteoclast activity and inflammation, and consequently improve the restoration of destroyed tissues. Collectively, our present study underscores the potential of CeO₂ NPs for application in the treatment of periodontitis, and provides valuable insights into the application of nanozymes in inflammatory diseases.

Remodeling the periodontitis microenvironment for osteogenesis by using a reactive oxygen species-cleavable nanoplatform

Modestly removing the excessive reactive oxygen species (ROS) plays a crucial role in regulating the microenvironment of periodontitis and provides favorable conditions for osteogenesis. However, the current strategy for scavenging ROS is not controllable, substantially limiting the outcomes in periodontitis. Herein, we introduced a controllable ROS-scavenging nanoplatform by encasing N-acetylcysteine (NAC, (a well-known ROS scavenger) into tailor-made ROS-cleavable amphiphilic polymer nanoparticles (PEG-ss-PCL NPs) as an intracellular delivery carrier. The existing ROS in the inflammatory microenvironment facilitated polymer degradation via breakage of thioketal bonds, and then led to encapsulated NAC release. NAC eliminated all ROS induced by lipopolysaccharide (LPS), while PssL-NAC adjusted the ROS level slightly higher than that of the control group. The percentage of apoptotic cells cultured with NAC and PssL-NAC decreased observably compared with that of cells cultured with 10 µg/ml LPS. The microenvironment regulated by PssL-NAC was highly suitable for osteogenic differentiation based on PCR and Western blot results, which showed higher expression levels of BMP2, Runx2, and PKA. Analysis of ALP activity and Alizarin red S staining showed consistent results. Additionally, the injection of PssL-NAC into the periodontitis area could alleviate the tissue destruction induced by ligation of the maxillary second molar. PssL-NAC showed a better ability to decrease osteoclast activity and inflammation, consequently improving the restoration of destroyed tissue. Our study suggests that ROS-responsive polymer nanoparticles loaded with NAC (PssL-NAC) can be new promising materials for the treatment of periodontitis. STATEMENT OF SIGNIFICANCE: More and more studies indicate that periodontal tissue damage is closely related to the high reactive oxygen species (ROS) environment. Excessive ROS will aggravate periodontal tissue damage and is not conducive to tissue repair. However, as an essential signal molecule in human physiological activities, ROS absence is also useless for tissue repair. In this study, we proposed to improve ROS imbalance in the environment of periodontitis as a strategy to promote periodontal regeneration and successfully synthesized a smart drug-releasing nanoplatform that can respond to ROS. Besides, we validated its ability to regulate the ROS environment and promote osteogenesis through experimental data in vivo and in vitro.

Paeonol assists fluconazole and amphotericin B to inhibit virulence factors and pathogenicity of Candida albicans

This study aimed to evaluate the mono- and dual- antifungal activities of paeonol (PAE) and fluconazole (FLZ)/amphotericin B (AmB). To this end, the effects of PAE and FLZ/AmB on cell surface hydrophobicity, hydrolase activity, morphological transition were investigated in vitro and in a Galleria mellonella infection model. The results showed a relatively high minimum inhibitory concentration (MIC) and sessile MIC (SMIC) of PAE alone. However, compared with the single drug, the combined use of PAE and FLZ/AmB had a potent synergistic potential to inhibit the virulence factors for Candida. The concomitant use of two drugs was consistently more effective than either drug alone for increasing survival rate, decreasing the fungal burden, and alleviating the pathological features of G. mellonella infected by the fungus. Taken together, these findings demonstrate the anti-Candida effects of PAE plus FLZ/AmB and their potential to increase the sensitivity of C. albicans to FLZ/AmB of PAE.

The circadian clock gene Bmal1: Role in COVID-19 and periodontitis

The physiological processes of most living organisms follow a rhythmic pattern, which is controlled by the interaction between environmental cues and the internal circadian timing system. Different regulatory circadian genes are expressed in most cells and tissues, and disruptions in the sleep-wake cycle affect these genes, which may result in metabolic disorders and cause alterations of the immune system. The manifestations of these disrupted genes are evident in inflammatory conditions such as periodontitis and some viral diseases, including COVID-19. The brain and muscle ARNT-like protein-1 (Bmal1), an important circadian regulatory gene, decreases when the sleep-wake cycle is disrupted. Circadian genes have been linked to different events, including cytokine storm in inflammatory conditions and virus invasion. The evaluation of the effects of these regulatory circadian genes, especially Bmal1, in periodontitis and viral infection suggests that both diseases may have a common pathogenesis via the NF-κB pathway. This brief review highlights the role and importance of the circadian clock gene Bmal1 in the disease process of periodontitis and suggests its role and importance in viral infections, including COVID-19.

Paeonolide as a Novel Regulator of Core-Binding Factor Subunit Alpha-1 in Bone-Forming Cells

Paeonia suffruticosa has been extensively used as a traditional medicine with various beneficial effects; paeonolide (PALI) was isolated from its dried roots. This study aimed to investigate the novel effects and mechanisms of PALI in pre-osteoblasts. Here, cell viability was evaluated using an MTT assay. Early and late osteoblast differentiation was examined by analyzing the activity of alkaline phosphatase (ALP) and by staining it with Alizarin red S (ARS). Cell migration was assessed using wound healing and Boyden chamber assays. Western blot and immunofluorescence analyses were used to examine the intracellular signaling pathways and differentiation proteins. PALI (0.1, 1, 10, 30, and 100 μM) showed no cytotoxic or proliferative effects in pre-osteoblasts. In the absence of cytotoxicity, PALI (1, 10, and 30 μM) promoted wound healing and transmigration during osteoblast differentiation. ALP staining demonstrated that PALI (1, 10, and 30 μM) promoted early osteoblast differentiation in a dose-dependent manner, and ARS staining showed an enhanced mineralized nodule formation, a key indicator of late osteoblast differentiation. Additionally, low concentrations of PALI (1 and 10 μM) increased the bone morphogenetic protein (BMP)–Smad1/5/8 and Wnt–β-catenin pathways in osteoblast differentiation. Particularly, PALI (1 and 10 μM) increased the phosphorylation of ERK1/2 compared with BMP2 treatment, an FDA-approved drug for bone diseases. Furthermore, PALI-mediated early and late osteoblast differentiation was abolished in the presence of the ERK1/2 inhibitor U0126. PALI-induced RUNX2 (Cbfa1) expression and nuclear localization were also attenuated by blocking the ERK1/2 pathway during osteoblast differentiation. We suggest that PALI has biologically novel activities, such as enhanced osteoblast differentiation and bone mineralization mainly through the intracellular ERK1/2-RUNX2 signaling pathway, suggesting that PALI might have therapeutic action and aid the treatment and prevention of bone diseases, such as osteoporosis and periodontitis.

Syndecan 4 contributes to osteoclast differentiation induced by RANKL through enhancing autophagy

Periodontitis is a common chronic disease. Osteoclast differentiation contributes to alveolar bone resorption which is a distinct phenomenon during periodontitis. Syndecan 4 (SDC4), a member of the syndecan family, was found to be highly expressed during periodontitis. However, little is known about its role in periodontitis. Herein, we explored the role of SDC4 in osteoclast differentiation. An experimental periodontitis rat model was established by ligating the right first molar. The SDC4 expression in periodontium was detected by western blot and immunofluorescence. Our study demonstrated that SDC4 was highly expressed in the periodontium of periodontitis rats. It was positively transcriptionally regulated by NF-κB. SDC4 silencing abrogated osteoclast differentiation induced by RANKL, while SDC4 overexpression enhanced osteoclast differentiation. Moreover, SDC4 enhanced autophagy induced by RANKL. 3-MA, an autophagy inhibitor, was employed to explore whether SDC4 impacts osteoclast differentiation through activating autophagy. Treatment with 3-MA abolished osteoclast differentiation which was enhanced by SDC4, indicating that SDC4 promotes osteoclast differentiation through activating autophagy. This study reveals that SDC4 may contribute to osteoclast differentiation during periodontitis through activating autophagy. It sheds light on the important role of SDC4 in periodontitis.

Paeonol protects melanocytes against hydrogen peroxide-induced oxidative stress through activation of Nrf2 signaling pathway

Oxidative stress plays a pivotal role in the pathogenesis of vitiligo. Paeonol, a phenolic compound found in the root bark of Cortex Moutan, has been suggested to have therapeutic effects on various diseases through nuclear factor Nrf2 mediated antioxidant pathways. However, the therapeutic effects of paeonol on vitiligo have not been investigated. In this study, we investigated whether paeonol could protect melanocytes against oxidative stress through Nrf2 activation. Hydrogen peroxide (H₂ O₂ ) was used to mimic the oxidative stress. PIG1 cells were pretreated with paeonol for 24 h, and then were treated with H₂ O₂ for 24 h. To detect the role of Nrf2, siRNA method was used to knockdown the Nrf2 expression. After that, cell viability, melanin content, tyrosinase activity, intracellular reactive oxygen species, antioxidant enzymes activities, nuclear translocation of Nrf2, and mRNA expression of Nrf2 downstream antioxidant genes were detected. Paeonol improved cell viability and melanogenesis in PIG1 cells treated with H₂ O₂ . Paeonol also alleviated oxidative stress by restoring the activities of superoxide dismutase, catalase, and glutathione peroxidase. Paeonol promoted Nrf2 nuclear translocation and the expression of its downstream-regulated antioxidative genes under oxidative stress. Furthermore, Nrf2 knockdown by siRNA abolished the protective effects of paeonol on PIG1 cells against oxidative damage. Paeonol protected melanocytes against H₂ O₂ -induced oxidative stress by Nrf2 mediated antioxidant pathways. Paeonol is a potential therapeutic drug for vitiligo.

MiR-19b-3p accelerates bone loss after spinal cord injury by suppressing osteogenesis via regulating PTEN/Akt/mTOR signalling

Rapid and extensive bone loss, one of the skeletal complications after spinal cord injury (SCI) occurrence, drastically sacrifices the life quality of SCI patients. It has been demonstrated that microRNA (miRNA) dysfunction plays an important role in the initiation and development of bone loss post-SCI. Nevertheless, the effect of miR-19b-3p on bone loss after SCI is unknown and the accurate mechanism is left to be elucidated. The present work was conducted to explore the role of miR-19b-3p/phosphatase and tensin homolog deleted on chromosome ten (PTEN) axis on osteogenesis after SCI and further investigates the underlying mechanisms. We found that miR-19b-3p level was increased in the femurs of SCI rats with decreased autophagy. The overexpression of miR-19b-3p in bone marrow mesenchymal stem cells (BMSCs) targeted down-regulation of PTEN expression, facilitated protein kinase B (Akt) and mammalian target of rapamycin (mTOR) phosphorylation, and thereby suppressing BMSCs osteogenic differentiation via autophagy. Besides, the inhibiting effects of miR-19b-3p on osteogenic differentiation of BMSCs could be diminished by autophagy inducer rapamycin. Meanwhile, bone loss after SCI in rats was also reversed by antagomir-19b-3p treatment, suggesting miR-19b-3p was an essential target for osteogenic differentiation via regulating autophagy. These results indicated that miR-19b-3p was involved in bone loss after SCI by inhibiting osteogenesis via PTEN/Akt/mTOR signalling pathway.

Fraxinellone alleviates inflammation and promotes osteogenic differentiation in lipopolysaccharide-stimulated periodontal ligament stem cells by regulating the bone morphogenetic protein 2/Smad pathway

OBJECTIVE

The aim of the present study was to investigate the role of fraxinellone in periodontitis and identify its potential mechanisms.

DESIGN

Lipopolysaccharide-induced periodontal ligament stem cells (PDLSCs) was employed to simulate the periodontitis in vitro. The levels of inflammatory factors were evaluated. After treatment with fraxinellone, alkaline phosphatase activity was determined. Additionally, calcium nodules staining was evaluated by alizarin red staining and the expression of osteogenesis differentiation-associated proteins was detected using western blot analysis. Moreover, the levels of proteins in bone morphogenetic protein 2 (BMP2)/Smad pathway were measured. Subsequently, BMP2 was silenced by transfection with small hairpin RNA to explore the underlying mechanisms of fraxinellone in lipopolysaccharide-induced PDLSCs.

RESULTS

Lipopolysaccharide stimulation significantly upregulated the levels of inflammatory factors, which were inhibited by fraxinellone intervention. Moreover, fraxinellone notably promoted osteogenic differentiation and calcification shown by increasing levels of alkaline phosphatase, calcification and osteogenic marker proteins. Furthermore, the expression of BMP2, phosphorylated Smad1 and phosphorylated Smad5 was remarkably upregulated when fraxinellone exposure in lipopolysaccharide-induced PDLSCs. What's more, BMP2 silencing dramatically restored the effects of fraxinellone on inflammation and osteogenic differentiation of PDLSCs stimulated by lipopolysaccharide.

CONCLUSION

These data demonstrated that fraxinellone alleviates inflammation and promotes osteogenic differentiation in lipopolysaccharide-stimulated PDLSCs by regulating the BMP2/Smad pathway, providing experimental supports for the clinical application of fraxinellone in the treatment of periodontitis.

Potential Advantages of Bioactive Compounds Extracted From Traditional Chinese Medicine to Inhibit Bone Destructions in Rheumatoid Arthritis

Bone destruction is an important pathological feature of rheumatoid arthritis (RA), which finally leads to the serious decline of life quality in RA patients. Bone metabolism imbalance is the principal factor of bone destruction in RA, which is manifested by excessive osteoclast-mediated bone resorption and inadequate osteoblast-mediated bone formation. Although current drugs alleviate the process of bone destruction to a certain extent, there are still many deficiencies. Recent studies have shown that traditional Chinese medicine (TCM) could effectively suppress bone destruction of RA. Some bioactive compounds from TCM have shown good effect on inhibiting osteoclast differentiation and promoting osteoblast proliferation. This article reviews the research progress of bioactive compounds exacted from TCM in inhibiting bone destruction of RA, so as to provide references for further clinical and scientific research.

Four active monomers from Moutan Cortex exert inhibitory effects against oxidative stress by activating Nrf2/Keap1 signaling pathway

Paeonol, quercetin, β-sitosterol, and gallic acid extracted from Moutan Cortex had been reported to possess anti-oxidative, anti-inflammatory, and antitumor activities. This work aimed to illustrate the potential anti-oxidative mechanism of monomers in human liver hepatocellular carcinoma (HepG2) cells-induced by hydrogen peroxide (H2O2) and to evaluate whether the hepatoprotective effect of monomers was independence or synergy in mice stimulated by carbon tetrachloride (CCl4). Monomers protected against oxidative stress in HepG2 cells in a doseresponse manner by inhibiting the generation of reactive oxygen species, increasing total antioxidant capacity, catalase and superoxide dismutase (SOD) activities, and activating the antioxidative pathway of nuclear factor E2-related factor 2/Kelchlike ECH-associated protein 1 (Nrf2/Keap1) signaling pathway. We found that the in vitro antioxidant capacities of paeonol and quercetin were better than those of β-sitosterol and gallic acid. Furthermore, paeonol apparently diminished the levels of alanine transaminase and aspartate aminotransferase, augmented the contents of glutathione and SOD, promoted the expressions of Nrf2 and heme oxygenase-1 proteins in mice stimulated by CCl4. In HepG2 cells, paeonol, quercetin, β-sitosterol, and gallic acid play a defensive role against H2O2-induced oxidative stress through activating Nrf2/Keap1 pathway, indicating that these monomers have anti-oxidative properties. Totally, paeonol and quercetin exerted anti-oxidative and hepatoprotective effects, which is independent rather than synergy.

Hyperoside ameliorates periodontitis in rats by promoting osteogenic differentiation of BMSCs via activation of the NF-κB pathway

Hyperoside, as an active compound, widely exists in a large number of Chinese herbal medicines and has been reported to possess anti‐inflammatory and diuretic properties. However, the effects and underlying mechanisms of hyperoside on periodontitis have not been previously reported. In this study, we found that hyperoside ameliorates symptoms of periodontitis in a rat model, with improvements in alveolar bone resorption, relief of inflammatory infiltration, increase in orderly arrangement of collagen fibers and increase of osteogenic differentiation. In addition, hyperoside promoted proliferation, up‐regulated EdU‐positive cells, decreased cell‐cycle distribution and increased the protein expression of Ki67 and PCNA in rat bone mesenchymal stem cells (rBMSCs), as revealed by Cell Counting Kit‐8, EdU, flow cytometry and western blot analysis. Moreover, hyperoside significantly promoted osteogenic differentiation, as shown by quantitative RT‐PCR, western blot and alizarin red staining assays. Furthermore, hyperoside activated the nuclear factor‐κB (NF‐κB) signaling pathway in rBMSCs, similar to the results observed in vivo. Finally, BMS345541, an inhibitor of the NF‐κB signaling pathway, could reverse the effects of hyperoside on the biological functions in rBMSCs. In conclusion, our results suggest that hyperoside has potential therapeutic properties against periodontitis via promotion of proliferation and osteogenic differentiation of rBMSCs via activation of the NF‐κB signaling pathway.

Low-intensity Pulsed Ultrasound regulates alveolar bone homeostasis in experimental Periodontitis by diminishing Oxidative Stress

Periodontitis is a widespread oral disease that results in the loss of alveolar bone. Low-intensity pulsed ultrasound (LIPUS), which is a new therapeutic option, promotes alveolar bone regeneration in periodontal bone injury models. This study investigated the protective effect of LIPUS on oxidative stress in periodontitis and the mechanism underlying this process.

Methods: An experimental periodontitis model was induced by administering a ligature. Immunohistochemistry was performed to detect the expression levels of oxidative stress, osteogenic, and osteoclastogenic markers in vivo. Cell viability and osteogenic differentiation were analyzed using the Cell Counting Kit-8, alkaline phosphatase, and Alizarin Red staining assays. A reactive oxygen species assay kit, lipid peroxidation MDA assay kit, and western blotting were used to determine oxidative stress status in vitro. To verify the role of nuclear factor erythroid 2-related factor 2 (Nrf2), an oxidative regulator, during LIPUS treatment, the siRNA technique and Nrf2^-/- mice were used. The PI3K/Akt inhibitor LY294002 was utilized to identify the effects of the PI3K-Akt/Nrf2 signaling pathway.

Results: Alveolar bone resorption, which was experimentally induced by periodontitis in vivo, was alleviated by LIPUS via activation of Nrf2. Oxidative stress, induced via H₂O₂ treatment in vitro, inhibited cell viability and suppressed osteogenic differentiation. These effects were also alleviated by LIPUS treatment via Nrf2 activation. Nrf2 silencing blocked the antioxidant effect of LIPUS by diminishing heme oxygenase-1 expression. Nrf2^-/- mice were susceptible to ligature-induced periodontitis, and the protective effect of LIPUS on alveolar bone dysfunction was weaker in these mice. Activation of Nrf2 by LIPUS was accompanied by activation of the PI3K/Akt pathway. The oxidative defense function of LIPUS was inhibited by exposure to LY294002 in vitro.

Conclusions: These results demonstrated that LIPUS regulates alveolar bone homeostasis in periodontitis by attenuating oxidative stress via the regulation of PI3K-Akt/Nrf2 signaling. Thus, Nrf2 plays a pivotal role in the protective effect exerted by LIPUS against ligature-induced experimental periodontitis.

Cynanchum paniculatum and Its Major Active Constituents for Inflammatory-Related Diseases: A Review of Traditional Use, Multiple Pathway Modulations, and Clinical Applications

Cynanchum paniculatum Radix, known as Xuchangqing in Chinese, is commonly prescribed in Chinese Medicine (CM) for the treatment of various inflammatory diseases. The anti-inflammatory property of Cynanchum paniculatum can be traced from its wind-damp removing, collaterals' obstruction relieving, and toxins counteracting effects as folk medicine in CM. This paper systematically reviewed the research advancement of the pharmacological effects of Cynanchum paniculatum among a variety of human diseases, including diseases of the respiratory, circulatory, digestive, urogenital, hematopoietic, endocrine and metabolomic, neurological, skeletal, and rheumatological systems and malignant diseases. This review aims to link the long history of clinical applications of Cynanchum paniculatum in CM with recent biomedical investigations. The major bioactive chemical compositions of Cynanchum paniculatum and their associated action mechanism unveiled by biomedical investigations as well as the present clinical applications and future perspectives are discussed. The major focuses of this review are on the diverse mechanisms of Cynanchum paniculatum and the role of its active components in inflammatory diseases.

Cinnamtannin B-1 Prevents Ovariectomy-Induced Osteoporosis via Attenuating Osteoclastogenesis and ROS Generation

Osteoporosis (OP) is one of the common bone metabolic diseases that endangers postmenopausal women and the elders. Both excessive bone resorption caused by osteoclast over-activation and increased oxidative stress are associated with osteoporosis. Cinnamtannin B-1 (CB-1) is considered as a high-valued plant extract monomer due to its antioxidant properties. However, the mechanism of CB-1 impacts on reducing oxidative stress, inhibiting the production of reactive oxygen species (ROS) and osteoclast differentiation and preventing ovariectomy-induced osteoporosis are still unclear. In this study, the effects of CB-1 on nuclear factor κB (RANKL)-induced osteoclasts formation and differentiation in vitro and the potential therapeutic effect on ovariectomy (OVX)-induced osteoporosis in vivo are investigated. CB-1 was found to inhibit osteoclast formation and bone resorption function in a dose-dependent manner, and it inhibited specific genes related to osteoclast as well. Micro-CT and histopathological staining showed that CB-1 can effectively prevent OVX-induced osteoporosis. In addition, CB-1 treatment can effectively inhibit the production of reactive oxygen species (ROS) in vivo and in vitro. Mechanistically, CB-1 inhibits the activation of osteoclasts by inhibiting the activation of the NF-κB signaling pathway. In conclusion, CB-1 would be able to be used as a promising new drug strategy to inhibit RANKL-induced osteoclastogenesis and prevent ovariectomy-induced osteoporosis.

Paeonol alleviates dextran sodium sulfate induced colitis involving Candida albicans-associated dysbiosis

Inflammatory bowel disease (IBD), which consists of ulcerative colitis (UC) and Crohn's disease (CD), is a chronic inflammatory disorder of the gastrointestinal tract. Occurrence and development of UC have been associated with multiple potential causative factors, which include fungal dysbiosis. Growing evidence reveals that Candida albicans-associated dysbiosis is correlated with clinical deterioration in UC. Paeonol (PAE) is a commonly used traditional medicine with multiple reported properties including effective alleviation of UC. In this study, a murine UC model was established by colonizing mice with additional C. albicans via gavage prior to dextran sodium sulfate (DSS) administration. Effects of PAE treatment were also assessed at initiation and in preestablished C. albicans-associated colitis. The results showed that C. albicans supplementation could aggravate disease activity index (DAI), compromise mucosal integrity, exacerbate fecal and tissue fungal burdens, increase serum β-glucan and anti-Saccharomyces cerevisiae antibody (ASCA) levels, promote serum and colonic tissue pro-inflammatory cytokine secretion (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8) and decrease the anti-inflammatory cytokine IL-10 level. It also stimulated Dectin-1, TLR2 and TLR4 as well as expression of their downstream effector NF-κB in colonic tissue. After PAE treatment, the adverse impacts of C. albicans on colitis were relieved, via decreased receptor-associated local and systemic inflammation. Our study suggests that PAE should be a candidate for treatment of fungal dysbiosis-associated UC and may act through the Dectin-1/NF-κB pathway in collaboration with TLR2 and TLR4.

LAY SUMMARY

Candida albicans is believed to be an important stimulator in ulcerative colitice (UC) development. Suppressing the growth of intestinal C. albicans can be contributory to the amelioration of UC. Paeonol (PAE) is a commonly used traditional medicine with multiple biological functions. In this study, we observed that PAE could alleviate symptoms in mice UC model accompanying with burden reduction of C. albicans. Therefore, we suppose that PAE can be a candidate in the treatment of C. albicans-associated UC.

Paeonol protects against testicular ischaemia-reperfusion injury in rats through inhibition of oxidative stress and inflammation

Ischaemia-reperfusion (IR) is the most common form of testicular injury that results in oxidative damage and inflammation ending by subinfertility. Paeonol, a natural phenolic compound, exhibits antioxidant and anti-inflammatory effects. Thus, the present study investigated the role of paeonol in rat testicular IR injury. Thirty adult Wistar rats were randomly divided into five groups; sham, sham treated with paeonol, IR injury, and IR pre-treated with paeonol at low and high doses. Serum testosterone and testicular levels of malondialdehyde and reduced glutathione (GSH) besides superoxide dismutase (SOD) activity were determined. Gene quantifications for tumour necrosis factor-α (TNF-α), hypoxia-inducible factor-1α (HIF-1α) and heat shock protein 70 (HSP70) were also assessed. Histopathological pictures and the immunohistochemical expression of testicular nuclear factor erythroid 2-related factor 2 (Nrf2), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were shown. Pre-treatment with paeonol prevented the drop in serum testosterone, alongside with improvement of testicular malondialdehyde and GSH levels plus SOD activity. Paeonol regained the normal spermatogenesis with prevention of IR-induced increase in TNF-α, HIF-1α and HSP70 gene expression besides IL-1β and IL-6 immunostaining and reduction in Nrf2 protein expression. Paeonol exerted a dose-dependent beneficial effect on testicular IR injury. This effect was achieved by its antioxidant and anti-inflammatory effects.

Tetramethylpyrazine reduces inflammation levels and the apoptosis of LPS‑stimulated human periodontal ligament cells via the downregulation of miR‑302b

Periodontitis is the main cause of tooth or tissue loss. Human periodontal ligament stem cells (hPDLSCs), which have high proliferative, self-renewal and multi-differentiation abilities, are vital for the restoration of periodontitis-induced injuries. The anti-inflammatory and anti-apoptotic agent, tetramethylpyrazine (TMP), is a promising agent used for the protection of PDLSCs from apoptosis and inflammation induced by periodontitis. The aim of the present study was to investigate the effects of TMP on lipopolysaccharide (LPS)-stimulated hPDLSCs. LPS-stimulated hPDLSCs were established as the cell model. CCK-8 assay was performed to evaluate cell viability, western blot analysis was performed to measure protein expression and flow cytometry was performed to detect cell apoptosis levels. Detection kits were used to evaluate the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6. Reverse transcription-quantitative PCR analysis was performed to detect gene expression. TMP alleviated the effects of LPS on cell viability, inflammation levels and cell apoptosis. TMP downregulated microRNA (miR)-302b levels in LPS-stimulated cells. Transfection with miR-302b mimic reversed the anti-inflammatory and anti-apoptotic effects of TMP on LPS-stimulated cells. TMP reduced inflammation and the apoptosis of LPS-stimulated human periodontal ligament cells via the downregulation of miR-302b. The anti-inflammatory and anti-apoptotic effects exerted by TMP render it a promising agent for the protection of PDLSCs from injuries induced by periodontitis. The findings of the present study may aid in the development of a novel strategy for the treatment of periodontitis and may pave the way for further research.

Chemistry, pharmacokinetics, pharmacology and recent novel drug delivery systems of paeonol

Paeonol is a bioactive phenol present in Dioscorea japonica, Paeonia suffruticosa and Paeonia lactiflora. It is reported for various pharmacological activities.

AIM

To review chemistry, pharmacokinetics, pharmacological activities as well as various formulations of paeonol.

MATERIALS AND METHODS

A literature search was done using different search terms for paeonol by using different scientific databases like PubMed, Scopus and ProQuest. Scientific papers published during the period 1969 to 2019 were comprehensively reviewed.

KEY FINDINGS

Researchers have synthesized methoxy, ethoxy, piperazine, chromonylthiazolidine, phenol-phenylsulfonyl, alkyl ether, aminothiazole, tryptamine hybrids and paeononlsilatie derivatives to enhance the stability of paeonol. These derivatives were synthesized and evaluated for in vitro series of biological activities like anti-inflammatory, tyrosinase inhibitory, neuroprotective, anticancer and antiviral activity. Regardless of valuable therapeutic potential, the clinical use of paeonol is restricted due to poor water solubility, low oral bioavailability, low stability and high volatility at room temperature. To enhance the bioavailability of paeonol various formulations are prepared and evaluated for its activity. Paeonol formulations can be categorized as conventional-tablets, topical gel and hydrogel; polymeric delivery system-microparticles, microsponges, dendrimers, nanocapsules, polymeric nanoparticles, nanospheres; lipid-based delivery systems-microemulsion, self-micro-emulsifying drug delivery, liposome, transethosomes, ethosomes, niosomes, proniosomes, lipid-based nanoparticles and nanoemulsion of paeonol.

SIGNIFICANCE

Paeonol has a potential to be developed as a techno-commercial product with respect to its multi-faceted pharmacological properties. Even though in vitro and in vivo studies have been reported the important activities of paeonol, its commercial utilization requires extensive safety and efficacy data.

Paeonol alleviates primary dysmenorrhea in mice via activating CB2R in the uterus

BACKGROUND AND PURPOSE

Primary dysmenorrhea is the most common gynaecologic problem in menstruating women and is characterized by spasmodic uterine contraction and pain symptoms associated with inflammatory disturbances. Paeonol is an active phytochemical component that has shown anti-inflammatory and analgesic effects in several animal models. The aim of this study was to explore whether paeonol is effective against dysmenorrhea and to investigate the potential mechanism of cannabinoid receptor signalling.

EXPERIMENTAL APPROACH

Dysmenorrhea was established by injecting oestradiol benzoate into female mice. The effects of paeonol on writhing time and latency, uterine pathology and inflammatory mediators were explored. Isolated uterine smooth muscle was used to evaluate the direct effect of paeonol on uterine contraction.

KEY RESULTS

The oral administration of paeonol reduced dysmenorrhea pain and PGE2 and TNF-α expression in the uterine tissues of mice, and paeonol was found to be distributed in lesions of the uterus. Paeonol almost completely inhibited oxytocin-, high potassium- and Ca²⁺-induced contractions in isolated uteri. Antagonists of CB2R (AM630) and the MAPK pathway (U0126), but not of CB1R (AM251), reversed the inhibitory effect of paeonol on uterine contraction. Paeonol significantly blocked L-type Ca²⁺ channels and calcium influx in uterine smooth muscle cells via CB2R. Molecular docking results showed that paeonol fits well with the binding site of CB2R.

CONCLUSIONS AND IMPLICATIONS

Paeonol partially acts through CB2R to restrain calcium influx and uterine contraction to alleviate dysmenorrhea in mice. These results suggest that paeonol has therapeutic potential for the treatment of dysmenorrhea.

Paeonol: pharmacological effects and mechanisms of action

Paeonia suffruticosa possesses various medicinal benefits and has been used extensively in traditional oriental medicine for thousands of years. Paeonol is the main component isolated from the root bark of Paeonia suffruticosa. The pharmacological effects of Paeonia suffruticosa are mostly attributed to paeonol. Paeonol injection has been successfully applied in China for nearly 50 years for inflammation/pain-related indications. Currently, the dosage forms of paeonol approved by China Food and Drug Administration include tablet, injection, and external preparations such as ointment and adhesive plaster. So far, the clinical applications of paeonol are mainly focusing on the anti-inflammatory activity. Studies of other pharmacological activities of paeonol are developing rapidly, and which may play an important role in the future. Besides, substantial mechanisms of pharmacological action of paeonol have been clarified in recent years. In this review, we summarize the pharmacological effects anti-inflammatory, neuroprotective, anti-tumor, anti-cardiovascular diseases and associated mechanisms of action of paeonol up to date.