Icariin alleviates MSU-induced rat GA models through NF-κB/NALP3 pathway

Traditional herbal medicine: Therapeutic potential in acute gouty arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Acute gouty arthritis (AGA) is characterized by a rapid inflammatory reaction caused by the build-up of monosodium urate (MSU) crystals in the tissues surrounding the joints. This condition often associated with hyperuricemia (HUA), is distinguished by its symptoms of intense pain, active inflammation, and swelling of the joints. Traditional approaches in AGA management often fall short of desired outcomes in clinical settings. However, recent ethnopharmacological investigations have been focusing on the potential of Traditional Herbal Medicine (THM) in various forms, exploring their therapeutic impact and targets in AGA treatment.

AIM OF THE REVIEW

This review briefly summarizes the current potential pharmacological mechanisms of THMs - including active ingredients, extracts, and prescriptions -in the treatment of AGA, and discusses the relevant potential mechanisms and molecular targets in depth. The objective of this study is to offer extensive information and a reference point for the exploration of targeted AGA treatment using THMs.

MATERIALS AND METHODS

This review obtained scientific publications focused on in vitro and in vivo studies of anti-AGA THMs conducted between 2013 and 2023. The literature was collected from various journals and electronic databases, including PubMed, Elsevier, ScienceDirect, Web of Science, and Google Scholar. The retrieval and analysis of relevant articles were guided by keywords such as "acute gouty arthritis and Chinese herbal medicine," "acute gouty arthritis herbal prescription," "acute gouty arthritis and immune cells," "acute gouty arthritis and inflammation," "acute gouty arthritis and NOD-like receptor thermoprotein domain associated protein 3 (NLRP3)," "acute gouty arthritis and miRNA," and "acute gouty arthritis and oxidative stress."

RESULTS

We found that AGA has a large number of therapeutic targets, highlighting the effectiveness the potential of THMs in AGA treatment through in vitro and in vivo studies. THMs and their active ingredients can mitigate AGA symptoms through a variety of therapeutic targets, such as influencing macrophage polarization, neutrophils, T cells, natural killer (NK) cells, and addressing factors like inflammation, NLRP3 inflammasome, signaling pathways, oxidative stress, and miRNA multi-target interactions. The anti-AGA properties of THMs, including their active components and prescriptions, were systematically summarized and categorized based on their respective therapeutic targets.

CONCLUSION

phenolic, flavonoid, terpenoid and alkaloid compounds in THMs are considered the key ingredients to improve AGA. THMs and their active ingredients achieve enhanced efficacy through interactions with multiple targets, of which NLRP3 is a main therapeutic target. Nonetheless, given the intricate composition of traditional Chinese medicine (TCM), additional research is required to unravel the underlying mechanisms and molecular targets through which THMs alleviate AGA.

Epimedin B exerts an anti-inflammatory effect by regulating the MAPK/NF-κB/NOD-like receptor signalling pathways

Epimedin B (EB), a predominant compound found in Herba Epimedii, has been shown to be effective in the treatment of osteoporosis and peripheral neuropathy. However, the anti-inflammatory effect of EB has not yet been reported. The anti-inflammatory activity of EB was evaluated in a zebrafish inflammation model induced by copper sulfate (CuSO4) and tail cutting. Our findings demonstrated that EB effectively inhibited acute inflammation, mitigated the accumulation of reactive oxygen species (ROS), and ameliorated the neuroinflammation-associated impairment of locomotion in zebrafish. Moreover, EB regulates several genes related to the mitogen-activated protein kinase (MAPK)/nuclear factor-κB (NF-κB)/Nod-like receptor signalling pathways (mapk8b, src, mmp9, akt1, mapk14a, mapk14b, mapk1, egfra, map3k4, nfκb2, iκbαa, pycard, nlrp3 and caspase1) and inflammatory cytokine (stat6, arg1, irfɑ, stat1ɑ, il-1β, il-4, il-6, il-8, cox-2, ptges, tnf-α and tgf-β). Therefore, our findings indicate that EB could serve as a promising therapeutic candidate for treating inflammation.

Preparing a novel baicalin-loaded microemulsion-based gel for transdermal delivery and testing its anti-gout effect

We previously demonstrated that baicalin had efficacy against gouty arthritis (GA) by oral administration. In this paper, a novel baicalin-loaded microemulsion-based gel (B-MEG) was prepared and assessed for the transdermal delivery of baicalin against GA. The preparation method and transdermal capability of B-MEG was screened and optimized using the central composite design, Franz diffusion cell experiments, and the split-split plot design. Skin irritation tests were performed in guinea pigs. The anti-gout effects were evaluated using mice. The optimized B-MEG comprised of 50 % pH 7.4 phosphate buffered saline, 4.48 % ethyl oleate, 31.64 % tween 80, 13.88 % glycerin, 2 % borneol, 0.5 % clove oil and 0.5 % xanthan gum, with a baicalin content of (10.42 ± 0.08) mg/g and particle size of (15.71 ± 0.41) nm. After 12 h, the cumulative amount of baicalin permeated from B-MEG was (672.14 ± 44.11) μg·cm-2. No significant skin irritation was observed following B-MEG application. Compared to the model group, B-MEG groups significantly decreased the rate of auricular swelling (P < 0.01) and number of twists observed in mice (P < 0.01); and also reduced the rate of paw swelling (P < 0.01) and inflammatory cell infiltration in a mouse model of GA. In conclusion, B-MEG represents a promising transdermal carrier for baicalin delivery and can be used as a potential therapy for GA.

Exploring effect of herbal monomers in treating gouty arthritis based on nuclear factor-kappa B signaling: A review

Gouty arthritis (GA) is an inflammatory disease caused by disorders of the purine metabolism. Although increasing number of drugs have been used to treat GA with the deepening of relevant research, GA still cannot be cured by simple drug therapy. The nuclear factor-kappa B (NF-κB) signaling pathway plays a key role in the pathogenesis of GA. A considerable number of Chinese herbal medicines have emerged as new drugs for the treatment of GA. This article collected relevant research on traditional Chinese medicine monomers in the treatment of GA using NF-κB, GA, etc. as keywords; and conducted a systematic search of relevant published articles using the PubMed database. In this study, we analyzed the therapeutic effects of traditional Chinese medicine monomers on GA in the existing literature through in vivo and in vitro experiments using animal and cell models. Based on this review, we believe that traditional Chinese medicine monomers that can treat GA through the NF-κB signaling pathway are potential new drug development targets. This study provides research ideas for the development and application of new drugs for GA.

Research progress of risk factors and early diagnostic biomarkers of gout-induced renal injury

Gout renal injury has an insidious onset, no obvious symptoms, and laboratory abnormalities in the early stages of the disease. The injury is not easily detected, and in many cases, the patients have entered the renal failure stage at the time of diagnosis. Therefore, the detection of gout renal injury–related risk factors and early diagnostic biomarkers of gout renal injury is essential for the prevention and early diagnosis of the disease. This article reviews the research progress in risk factors and early diagnostic biomarkers of gout renal injury.

Palmatine Protects Against MSU-Induced Gouty Arthritis via Regulating the NF-κB/NLRP3 and Nrf2 Pathways

Purpose

Gouty arthritis could be triggered by the deposition of monosodium uric acid (MSU) crystals. Palmatine (PAL), a protoberberine alkaloid, has been proven to possess compelling health-beneficial activities. In this study, we aimed to explore the effect of PAL on LPS plus MSU crystal-stimulated gouty arthritis in vitro and in vivo.

Methods

PMA-differentiated THP-1 macrophages were primed with LPS and then stimulated with MSU crystal in the presence or absence of PAL. The expression of pro-inflammatory cytokines and oxidative stress-related biomarkers and signal pathway key targets were determined by ELISA kit, Western blot, immunohistochemistry and qRT-PCR, respectively. In addition, the anti-inflammatory and antioxidant activities of PAL on MSU-induced arthritis mice were also evaluated.

Results

The results indicated that PAL (20, 40 and 80 μM) dose-dependently decreased the mRNA expression and levels of pro-inflammatory cytokines (interleukin-1beta (IL-1β), IL-6, IL-18 and tumor necrosis factor alpha (TNF-α)). The levels of superoxide dismutase (SOD) and glutathione (GSH) were remarkably enhanced, while the level of malondialdehyde (MDA) was reduced. Western blot analysis revealed that PAL appreciably inhibited NF-κB/NLRP3 signaling pathways through inhibiting the phosphorylation of p-65 and IκBα, blocking the expression of NLRP3, ASC, IL-1β and Caspase-1, as well as enhancing the antioxidant protein expression of Nrf2 and HO-1. In vivo, PAL attenuated MSU-induced inflammation in gouty arthritis, as evidenced by mitigating the joint swelling, and decreasing the productions of IL-1β, IL-6, IL-18, TNF-α and MDA, while enhancing the levels of SOD and GSH. Moreover, PAL further attenuated the infiltration of neutrophils into joint synovitis.

Conclusion

PAL protected against MSU-induced inflammation and oxidative stress via regulating the NF-κB/NLRP3 and Nrf2 pathways. PAL may represent a potential candidate for the treatment of gouty arthritis.

Anti-inflammatory and immunoregulatory effects of icariin and icaritin

Inflammation and immunity dysregulation have received widespread attention in recent years due to their occurrence in the pathophysiology of many conditions. In this regard, several pharmacological studies have been conducted aiming to evaluate the potential anti-inflammatory and immunomodulatory effects of phytochemicals. Epimedium, a traditional Chinese medicine, is often used as a tonic, aphrodisiac, and anti-rheumatic agent. Icariin (ICA) is the main active ingredient of Epimedium and is, once ingested, mainly metabolized into Icaritin (ICT). Data from in vitro and in vivo studies suggested that ICA and its metabolite (ICT) regulated the functions and activation of immune cells, modulated the release of inflammatory factors, and restored aberrant signaling pathways. ICA and ICT were also involved in anti-inflammatory and immune responses in several diseases, including multiple sclerosis, asthma, atherosclerosis, lupus nephritis, inflammatory bowel diseases, rheumatoid arthritis, and cancer. Yet, data showed that ICA and ICT exhibited similar but not identical pharmacokinetic properties. Therefore, based on their higher solubility and bioavailability, as well as trends indicating that single-ingredient compounds offer broader and safer therapeutic capabilities, ICA and ICT delivery systems and treatment represent interesting avenues with promising clinical applications. In this study, we reviewed the anti-inflammatory and immunomodulatory mechanisms, as well as the pharmacokinetic properties of ICA and its metabolite ICT.

Tongbixiao Pills Improve Gout by Reducing Uric Acid Levels and Inhibiting Inflammation

Gout is a chronic disease. Gout symptoms are often experienced in the middle of the night. The onset of gout in the middle of the night is closely related to abnormal liver and gallbladder meridian. The purpose of this study was to investigate the clinical efficacy and possible mechanism of action of Tongbixiao pills in the treatment of hyperuricemia and gouty arthritis. The Tongbixiao pills we used included several traditional Chinese medicines, most of which tonify the spleen; strengthen the liver; benefit the kidney; and reduce heat, dampness, and blood stasis. In this randomized clinical study of 105 patients, we found that Tongbixiao pills can reduce uric acid levels in hyperuricemia patients. Additionally, the efficacy was similar to that of allopurinol and the level of uric acid did not increase significantly at eight weeks after withdrawal. In the absence of notable adverse reactions, Tongbixiao pills can also increase uric acid excretion, reduce serum creatinine and lipid levels, and reduce inflammation and relieve gout symptoms. In addition, we used SD rats to simulate gout and arthritis and divided them into five groups: normal group, model group, low-dose group, medium-dose group, and high-dose group. The inflammatory indices of the 40 SD rats were observed. After seven days, ankle swelling in rats in the treatment group was significantly reduced. The indices of uric acid, creatinine, and urea nitrogen in the treatment group were significantly lower than those in the model group, which proved that Tongbixiao pills could inhibit hyperuricemia in rats, thus treating gout. This study demonstrates that Tongbixiao pills can treat gout, provide more treatment options for gouty arthritis, and improve the quality of life of patients.

Influence of Pinealectomy and Long-term Melatonin Administration on Inflammation and Oxidative Stress in Experimental Gouty Arthritis

Gout is an inflammatory arthritis characterized by the deposition of monosodium urate (MSU) crystals in the joints or soft tissue. MSU crystals are potent inflammation inducers. Melatonin (MLT) is a powerful endogenous anti-inflammatory agent and effective in reducing cellular damage. In the present study, possible underlying mechanisms associated with anti-inflammatory and antioxidative effects were investigated in rats with gouty arthritis and melatonin deprivation treated with MLT. Fifty-six rats were divided into seven groups: control, sham control, pinealectomy (PNX), MSU (on the 30th day, single-dose 20 mg/ml, intraperitoneal), MSU + MLT (10 mg/kg/day for 30 days, intraperitoneal), MSU + PINX and MSU + PINX + MLT. PNX procedure was performed on the first day of the study. As compared to the controls, the results showed that MSU administration caused significant increases in oxidative stress parameters (malondialdehyde and total oxidant status). Besides, significant decreases in antioxidant defense systems (glutathione, superoxide dismutase and total antioxidant status) were observed. A statistically significant increase was found in the mean histopathological damage score in the groups that received MSU injection. It was found that histopathological changes were significantly reduced in the MSU + MLT group given MLT. In our study, it was determined that many histopathological changes, as well as swelling and temperature increase in the joint, which are markers of inflammation, were significantly reduced with MLT supplementation. These results suggest that melatonin ameliorates MSU-induced gout in the rat through inhibition of oxidative stress and proinflammatory cytokine production.

Advances in Experimental and Clinical Research of the Gouty Arthritis Treatment with Traditional Chinese Medicine

Gouty arthritis (GA) is a multifactorial disease whose pathogenesis is utterly complex, and the current clinical treatment methods cannot wholly prevent GA development. Western medicine is the primary treatment strategy for gouty arthritis, but it owns an unfavorable prognosis. Therefore, the prevention and treatment of GA are essential. In China, traditional Chinese medicine (TCM) has been adopted for GA prevention and treatment for thousands of years. Gout patients are usually treated with TCM according to their different conditions, and long-term results can be achieved by improving their physical condition. And TCM has been proved to be an effective method to treat gout in modern China. Nevertheless, the pharmacological mechanism of TCM for gout is still unclear, which limits its spread. The theory of prevention and treatment of gout with TCM is more well acknowledged in China than in abroad. In this article, Chinese herbs and ancient formula for gout were summarized first. A total of more than 570 studies published from 2004 to June 2021 in PubMed, Medline, CNKI, VIP, Web of Science databases and Chinese Pharmacopoeia and traditional Chinese books were searched; the current status of TCM in the treatment of GA was summarized from the following aspects: articular chondrocyte apoptosis inhibition, antioxidative stress response, inflammatory cytokine levels regulation, uric acid excretion promotion, immune function regulation, uric acid reduction, and intestinal flora improvement in subjects with gout. The literature review concluded that TCM has a specific curative effect on the prevention and treatment of GA, particularly when combined with modern medical approaches. However, lacking a uniform definition of GA syndrome differentiation and the support of evidence-based medicine in clinical practice have provoked considerable concern in previous studies, which needs to be addressed in future research.

Lactiplantibacillus plantarum HG20 attenuates II type collagen-induced rheumatoid arthritis in rats via anti-inflammatory and inhibition of apoptosis

AIMS

This study aimed to explore the therapeutic effects of Lactiplantibacillus plantarum HG20 (HG20) on collagen-induced arthritis (CIA) rats and its mechanism.

METHODS AND RESULTS

CIA rats were established by injecting bovine type II collagen for 7 days, and treated by intragastric administration HG20 for 21 days. The foot palm temperature and arthritis score were measured once a week. The pathological changes in the knee joint were observed by hematoxylin and eosin staining. The levels of cytokines were detected by enzyme linked immunosorbent assay, and the effects of HG20 on inflammatory and apoptosis pathway of spleen cells were detected by western blot analysis. The results indicated that HG20 reduced the joint swelling degree and foot palm temperature, inhibited the development of joint histopathology, decreased the levels of pro-inflammatory cytokines, down-regulate the expression of pro-inflammatory cytokines by nuclear factor kappa-B pathway, and inhibited the apoptosis of spleen cells by inhibiting phosphatidylinositol 3-kinase/protein kinase B pathway and regulating apoptosis pathways.

CONCLUSIONS

HG20 had an adjuvant therapeutic effect on arthritis in CIA rats, and its mechanism might be related to the inflammatory and apoptosis pathway.

SIGNIFICANCE AND IMPACT OF STUDY

These results revealed that HG20 could be used as a functional probiotic in the field of food and medical, and which played a potential role in the prevention and treatment of arthritis.

Flavonoids: Nutraceuticals for Rheumatic Diseases via Targeting of Inflammasome Activation

Inflammation, an innate immune response that prevents cellular damage caused by pathogens, consists of two successive mechanisms, namely priming and triggering. While priming is an inflammation-preparation step, triggering is an inflammation-activation step, and the central feature of triggering is the activation of inflammasomes and intracellular inflammatory protein complexes. Flavonoids are natural phenolic compounds predominantly present in plants, fruits, and vegetables and are known to possess strong anti-inflammatory activities. The anti-inflammatory activity of flavonoids has long been demonstrated, with the main focus on the priming mechanisms, while increasing numbers of recent studies have redirected the research focus on the triggering step, and studies have reported that flavonoids inhibit inflammatory responses and diseases by targeting inflammasome activation. Rheumatic diseases are systemic inflammatory and autoimmune diseases that primarily affect joints and connective tissues, and they are associated with numerous deleterious effects. Here, we discuss the emerging literature on the ameliorative role of flavonoids targeting inflammasome activation in inflammatory rheumatic diseases.