Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the synovial joints, deformities, and disability. The prolonged use of conventional anti-inflammatory drugs is associated with severe adverse effects. Therefore, there is an urgent need for safer and less expensive therapeutic products. Celastrol is a bioactive component of Celastrus, a traditional Chinese medicine, and it possesses anti-arthritic activity. However, the mechanism of action of Celastrol remains to be fully defined. In this study based on the rat adjuvant-induced arthritis (AA) model of RA, we examined the effect of Celastrol on two of the key mediators of arthritic inflammation, namely chemokines and their receptors, and related pro-inflammatory cytokines. We treated arthritic Lewis rats with Celastrol (200 μg/rat) or its vehicle by daily intraperitoneal (i.p.) injection beginning at the onset of AA. At the peak phase of AA, the sera, the draining lymph node cells, spleen adherent cells, and synovial-infiltrating cells of these rats were harvested and tested. Celastrol-treated rats showed a significant reduction in the levels of chemokines (RANTES, MCP-1, MIP-1α, and GRO/KC) as well as cytokines (TNF-α and IL-1β) that induce them, compared to the vehicle-treated rats. However, Celastrol did not have much effect on cellular expression of chemokine receptors except for an increase in CCR1. Further, Celastrol inhibited the migration of spleen adherent cells in vitro. Thus, Celastrol-induced suppression of various chemokines that mediate cellular infiltration into the joints might contribute to its anti-arthritic activity. Our results suggest that Celastrol might offer a promising alternative/adjunct treatment for RA
Inflammation; arthritis; chemokines; cytokines; traditional Chinese medicine; natural plant products; animal model
Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the joints. The prolonged use of anti-inflammatory drugs and other newer drugs is associated with severe adverse reactions. Therefore, there is a need for newer anti-arthritic agents. Celastrol, a bioactive component of the Chinese herb Celastrus, possesses anti-arthritic activity as tested in the adjuvant arthritis (AA) model of rheumatoid arthritis (RA). However, the mechanism of action of Celastrol has not been fully defined. We reasoned that microarray analysis of the lymphoid cells of Celastrol-treated arthritic animals might provide vital clues in this regard. We isolated total RNA of the draining lymph node cells (LNC) of Celastrol-treated (Tc) and vehicle-treated (Tp) arthritic Lewis rats, restimulated them in vitro with the disease-related antigen, mycobacterial heat-shock protein 65 (Bhsp65), and tested it using microarray gene chips. Also tested were control arthritic rats just before any treatment (T0). Seventy six genes involved in various biological functions were differentially regulated by Bhsp65 in LNC of Tp group, and 19 genes among them were shared by the Tc group. Furthermore, a group of 14 genes was unique to Tc, indicating that Celastrol modulated not only arthritis-related genes but also those involved in other defined pathways. When Tc and Tp were compared, many of the Bhsp65-induced genes were related to the immune cells, cellular proliferation and inflammatory responses. Our results revealed 10 differentially expressed genes and 14 pathways that constituted the “Celastrol Signature”. Our results would help identify novel targets for therapeutic purposes.
Arthritis; Celastrus; Celastrol; Inflammation; Gene expression; Microarray
Rheumatoid arthritis (RA) is an autoimmune disease characterized by chronic inflammation of the synovial joints leading to bone and cartilage damage. Untreated inflammatory arthritis can result in severe deformities and disability. The use of anti-inflammatory agents and biologics has been the mainstay of treatment of RA. However, the prolonged use of such agents may lead to severe adverse reactions. In addition, many of these drugs are quite expensive. These limitations have necessitated the search for newer therapeutic agents for RA. Natural plant products offer a promising resource for potential antiarthritic agents. We describe here the cellular and soluble mediators of inflammation-induced bone damage (osteoimmunology) in arthritis. We also elaborate upon various herbal products that possess antiarthritic activity, particularly mentioning the specific target molecules. As the use of natural product supplements by RA patients is increasing, this paper presents timely and useful information about the mechanism of action of promising herbal products that can inhibit the progression of inflammation and bone damage in the course of arthritis.
This study was aimed at examining the effect of an ointment containing essential oils (EO) on the severity of adjuvant arthritis (AA), an experimental model of human rheumatoid arthritis (RA), in Lewis rats and to define the underlying mechanisms. At the onset of AA, rats received topical application twice daily of ointment containing 20% EO or placebo ointment. The synovial fluid (SF) and synovium-infiltrating cells (SIC) of rats were tested for pro-inflammatory cytokines TNF-α and IL-1β. The hind paws and skin were examined histologically. The activity/level of matrix metalloproteinases (MMPs) and anti-mycobacterial heat-shock protein 65 (Bhsp65) antibodies was tested. Arthritic rats treated with ointment containing EO developed less severe clinical arthritis compared to the controls, and this activity was attributable to EO and not the carrier oil. The levels of TNF-α and IL-1β, and the activity of MMPs in SF and SIC-lysate were significantly (p<0.05) reduced in EO-treated arthritic rats compared to the controls. However, the levels of anti-Bhsp65 antibodies were unaffected by treatment. Thus, topical dermal delivery of EO-containing ointment downmodulates the severity of AA in Lewis rats by inhibiting defined mediators of inflammation. Such ointments should be tested in patients with RA and other arthritic conditions.
Essential oils; Arthritis; Cytokines; Topical application; MMPs; Inflammation
Cytokines are immune mediators that play an important role in the pathogenesis of rheumatoid arthritis (RA), an autoimmune disease that targets the synovial joints. The cytokine environment in the peripheral lymphoid tissues and the target organ (the joint) has a strong influence on the outcome of the initial events that trigger autoimmune inflammation. In susceptible individuals, these events drive inflammation and tissue damage in the joints. However, in resistant individuals, the inflammatory events are controlled effectively with minimal or no overt signs of arthritis. Animal models of human RA have permitted comprehensive investigations into the role of cytokines in the initiation, progression, and recovery phases of autoimmune arthritis. The discovery of interleukin-17 (IL-17) and its association with inflammation and autoimmune pathology has reshaped our viewpoint regarding the pathogenesis of arthritis, which previously was based on a simplistic T helper 1 (Th1)-Th2 paradigm. This review discusses the role of the newer cytokines, particularly those associated with the IL-17/IL-23 axis in arthritis. Also presented herein is the emerging information on IL-32, IL-33, and IL-35. Ongoing studies examining the role of the newer cytokines in the disease process would improve understanding of RA as well as the development of novel cytokine inhibitors that might be more efficacious than the currently available options.
Several lines of evidence strongly implicate type I interferons (IFN-α and β) and IFN-signaling in the pathogenesis of certain autoimmune inflammatory diseases. Accordingly, genome-wide association studies have identified polymorphisms in the type I IFN-signaling pathways. Other studies also indicate that a feed-forward loop of type I IFN production, which involves sensing of cytoplasmic nucleic acids by sensors, contributes to the development of immunopathology. In addition, a mutually positive regulatory feedback loop between type I IFNs and estrogen receptor-α may contribute to a gender bias, thus resulting in an increased production of type I IFNs and associated immunopathology in women. Increased levels of type I IFNs have numerous immunomodulatory functions for both the innate and adaptive immune responses. Given that the IFN-β also has some anti-inflammatory roles, identifying molecular links among certain genotypes, cytokine profiles, and associated phenotypes in patients with autoimmune inflammatory diseases is likely to improve our understanding of autoimmunity-associated pathogenesis and suboptimal outcomes following standard therapies.
Cytokines play a pivotal role in the pathogenesis of autoimmune diseases. The precise triggers for the breakdown of self-tolerance and the subsequent events leading to the induction of pathogenic autoimmune responses remain to be defined for most of the naturally occurring autoimmune diseases. Studies conducted in experimental models of human autoimmune diseases and observations in patients have revealed a general scheme in which proinflammatory cytokines contribute to the initiation and propagation of autoimmune inflammation, whereas anti-inflammatory cytokines facilitate the regression of inflammation and recovery from acute phase of the disease. This idea is embodied in the T helper (Th) 1/Th2 paradigm, which over the past two decades has had a major influence on our thinking about the role of cytokines in autoimmunity. Interestingly, over the past decade, the interleukin (IL)-17/IL-23 axis has rapidly emerged as the new paradigm that has compelled us to critically re-examine the cytokine-driven immune events in the pathogenesis and treatment of autoimmunity. In this 2-volume special issue of the journal, leading experts have presented their research findings and viewpoints on the role of cytokines in the context of specific autoimmune diseases.
To review the literature on the role of heat-shock proteins (HSPs) in the pathogenesis of autoimmune arthritis in animal models ans patients with rheumatoid arthritis (RA).
The published literature in Medline (PubMed), including our published work on the cell-mediated as well as humoral immune response to various HSPs was reviewed. Studies in both the pre-clinical animal models of arthritis as well as RA were examined critically and the data presented.
In experimental arthritis, disease induction by different arthritogenic stimuli, including an adjuvant, led to immune response to mycobacterial HSP65 (BHSP65). However, attempts to induce arthritis by a purified HSP have not met with success. There are several reports of a significant immune response to HSP65 in RA patients. But, the issue of cause and effect is difficult to address. Nevertheless, several studies in animal models and a couple of clinical trials in RA patients have shown the beneficial effect of HSPs against autoimmune arthritis.
There is a clear association between immune response to HSPs, particularly HSP65, and the initiation and propagation of autoimmune arthritis in experimental models. The correlation is relatively less convincing in RA patients. In both cases, the ability of HSPs to modulate arthritis offers support, albeit an indirect one, for the involvement of these antigens in the disease process.
Heat-shock proteins (Hsps) have been invoked in the pathogenesis of a variety of autoimmune diseases. The mycobacterial heat-shock protein 65 (Bhsp65) has been studied extensively as one of the antigenic triggers of autoimmunity in experimental models of, as well as patients with, rheumatoid arthritis. As Hsps are highly conserved and immunogenic, it is generally anticipated that self Hsps might serve as the endogenous targets of the immune response initiated by the homologous foreign Hsps. Contrary to this expectation, studies in the rat adjuvant arthritis (AA) model have revealed that priming of the self (rat) hsp65 (Rhsp65)-directed T cells in the Lewis rat leads to protection against AA instead of disease induction or aggravation. The arthritis-protective attribute of the self hsp65 is also evident following spontaneous priming of the anti-Rhsp65 T cells during the natural course of AA. Furthermore, immunization of rats with human hsp60, or with Bhsp65 peptides that are crossreactive with the corresponding self hsp65 peptides, leads to protection against AA. Importantly, high levels of T cell reactivity against self hsp60 in patients with juvenile idiopathic arthritis positively correlate with a favorable outcome of the disease. Thus, immune response against self hsp65 in autoimmune arthritis is protective rather than being pathogenic.
Adjuvant arthritis; Autoimmunity; Heat-shock protein 65; Immunoregulation; Juvenile Idiopathic Arthritis
Rheumatoid arthritis (RA) is a debilitating autoimmune disease. Smoking is an important environmental factor in a subset of RA patients. Furthermore, the role of the cholinergic anti-inflammatory pathway in autoimmune inflammation is increasingly being realized. Nicotine is a major component of cigarette smoke and it also stimulates the α7-nicotinic acetylcholine receptors. Therefore, defining the mechanisms underlying the immunomodulatory effects of nicotine on arthritis is of high relevance. We have addressed this using the rat adjuvant-induced arthritis model of human RA.
Lewis rats were immunized s.c. with heat-killed M. tuberculosis H37Ra (Mtb) for disease induction. Rats were treated with nicotine i.p. either before (pretreatment) or after (posttreatment) the onset of AA. Control rats received the vehicle (buffer) in place of nicotine. The severity of arthritis was assessed and graded. The draining lymph node cells (LNC) were tested for T cell proliferative and cytokine responses against the disease-related antigen, mycobacterial heat-shock protein 65 (Bhsp65). The sera were tested for anti-cyclic citrullinated peptide antibodies (a-CCP) and anti-Bhsp65 antibodies.
Nicotine-pretreatment aggravated arthritis, whereas nicotine posttreatment suppressed the disease. This altered severity of AA directly correlated with the levels of the aCCP antibodies, of the Th1/Th17 cytokines, and of the corresponding dendritic cell-derived cytokines. The majority of these effects on cellular responses could be replicated in vitro.
Nicotine-induced modulation of AA involves specific alterations in the disease-related cellular and humoral immune responses in AA. These results are of significance in advancing our understanding of the pathogenesis of RA.
Experimental models of rheumatoid arthritis (RA) have contributed immensely to our understanding of the pathogenesis as well as the treatment of this debilitating autoimmune disease. Significant progress has been made in the past few years in defining the role of newer cytokines and regulatory T cells, of inflammation-mediated bone and cartilage damage, and of the cholinergic anti-inflammatory pathway in modulating the disease process in arthritis. Furthermore, new therapeutic targets, including specific tyrosine kinases and proteasome subunits have been explored. These advances offer renewed optimism for continued improvements in the management of RA.
Rheumatoid arthritis (RA) is a chronic debilitating disease characterized by synovial inflammation, damage to cartilage and bone, and deformities of the joints. Several drugs possessing anti-inflammatory and immunomodulatory properties are being used in the conventional (allopathic) system of medicine to treat RA. However, the long-term use of these drugs is associated with harmful side effects. Therefore, newer drugs with low or no toxicity for the treatment of RA are actively being sought. Interestingly, several herbs demonstrate anti-inflammatory and anti-arthritic activity. In this review, we describe the role of the major biochemical and molecular mediators in the pathogenesis of RA, and highlight the sites of action of herbal medicinal products that have anti-arthritic activity. With the rapidly increasing use of CAM products by patients with RA and other inflammation-related disorders, our review presents timely information validating the scientific rationale for the use of natural therapeutic products.
Complementary and alternative medicine (CAM); Herbal products; Inflammatory mediators; Rheumatoid arthritis (RA)
Rheumatoid arthritis (RA) is a debilitating autoimmune disease of global prevalence. The disease is characterized by synovial inflammation leading to cartilage and bone damage. Most of the conventional drugs used for the treatment of RA have severe adverse reactions and are quite expensive. Over the years, increasing proportion of patients with RA and other immune disorders are resorting to complementary and alternative medicine (CAM) for their health needs. Natural plant products comprise one of the most popular CAM for inflammatory and immune disorders. These herbal CAM belong to diverse traditional systems of medicine, including traditional Chinese medicine, Kampo, and Ayurvedic medicine. In this paper, we have outlined the major immunological pathways involved in the induction and regulation of autoimmune arthritis and described various herbal CAM that can effectively modulate these immune pathways. Most of the information about the mechanisms of action of herbal products in the experimental models of RA is relevant to arthritis patients as well. The study of immunological pathways coupled with the emerging application of genomics and proteomics in CAM research is likely to provide novel insights into the mechanisms of action of different CAM modalities.
Rheumatoid arthritis (RA) is a chronic inflammatory disease of autoimmune origin. Huo-luo-xiao-ling dan (HLXL) is an herbal mixture that has been used in traditional Chinese medicine over several decades to treat chronic inflammatory diseases including RA. However, the mechanism of the anti-arthritic action of this herbal remedy is poorly understood at the molecular level. In this study, we determined by microarray analysis the effects of HLXL on the global gene expression profile of the draining lymph node cells (LNC) in the rat adjuvant arthritis (AA) model of human RA. In LNC restimulated in vitro with the disease-related antigen mycobacterial heat-shock protein 65 (Bhsp65), 84 differentially expressed genes (DEG) (64 upregulated and 20 downregulated) versus 120 DEG (94 upregulated and 26 downregulated) were identified in HLXL-treated versus vehicle (Water)-treated rats, respectively, and 62 DEG (45 upregulated and 17 downregulated) were shared between the two groups. The most affected pathways in response to HLXL treatment included immune response, inflammation, cellular proliferation and apoptosis, and metabolic processes, many of which are directly relevant to arthritis pathogenesis. These results would advance our understanding of the mechanisms underlying the anti-arthritic activity of HLXL.
Heat-shock proteins (Hsps) are among the most highly conserved and immunogenic proteins shared by microbial agents and mammals. Under physiological conditions, the ubiquitously distributed Hsps maintain the integrity and function of other cellular proteins when cells are exposed to stressful stimuli. However, owing to their conserved nature and stress inducibility, Hsps may become targets of immune response. The T cells and/or antibodies induced by a microbial Hsp may crossreact with the corresponding mammalian Hsp (molecular mimicry) and trigger an autoimmune response, which if unchecked can lead to immune pathology and clinical manifestations. Furthermore, enhanced expression of Hsp under stress can unveil previously hidden antigenic determinants that can initiate and perpetuate autoimmune reactivity. Also, the innate immune mechanisms activated by an Hsp can reinforce and even direct the type of adaptive immune response to that protein. Hsps have been implicated in the induction and propagation of autoimmunity in several diseases, including rheumatoid arthritis, atherosclerosis and type 1 diabetes. However, Hsps possess immunoregulatory attributes as well and therefore, are being exploited for immunomodulation of various immune-mediated disorders.
Autoimmunity; Heat-shock proteins; Immunomodulation; Inflammation; Molecular mimicry; Stress proteins
The pro-inflammatory cytokines play a critical role in the initiation and propagation of autoimmune arthritis and many other disorders resulting from a dysregulated self-directed immune response. These cytokines influence the interplay among the cellular, immunological and biochemical mediators of inflammation at multiple levels. Regulation of the pro-inflammatory activity of these cytokines is generally perceived to be mediated by the anti-inflammatory and immunosuppressive cytokines such as IL-4, IL-10, or TGF-β. However, increasing evidence is accumulating in support of the regulatory attributes of the pro-inflammatory cytokines themselves, in studies conducted in animal models of diabetes, multiple sclerosis, uveitis, and lupus. The results of our recent studies have shown that the pro-inflammatory cytokines, TNF-α and IFN-γ, can suppress arthritic inflammation in rats, and also contribute to resistance against arthritis. These results are of paramount significance not only in fully understanding the pathogenesis of autoimmune arthritis, but also in anticipating the full ramifications of the in vivo neutralization of the pro-inflammatory cytokines, including that for therapeutic purposes.
The pathogenesis of T cell-mediated diseases like rheumatoid arthritis (RA) has typically been explained in the context of the Th1-Th2 paradigm: the initiation/propagation by pro-inflammatory cytokines, and downregulation by Th2 cytokines. However, in our study based on the adjuvant-induced arthritis (AA) model of RA, we observed that Lewis (LEW) (RT.1l) rats at the recovery phase of AA showed the highest level of IFN-γ in recall response to mycobacterial heat-shock protein 65 (Bhsp65), whereas AA-resistant Wistar-Kyoto (WKY) (RT.1l) rats secreted high levels of IFN-γ much earlier following disease induction. However, no significant secretion of IL-10 or TGF-β was observed in either strain. Furthermore, pre-treatment of LEW rats with a peptide of self (rat) hsp65 (R465), which induced T cells secreting predominantly IFN-γ, afforded protection against AA and decreased IL-17 expression by the arthritogenic epitope-restimulated T cells. These results provide a novel perspective on the pathogenesis of autoimmune arthritis.
Animal Models; Arthritis; Autoimmunity; Cytokines; Immune Regulation
Huo-luo-xiao-ling dan (HLXL) is an herbal mixture that has long been used in traditional Chinese medicine for the treatment of rheumatoid arthritis (RA) and other inflammatory disorders. Despite the availability of potent conventionally used drugs for RA, their limited efficacy in a proportion of patients coupled with their high cost and severe adverse effects has necessitated the search for novel therapeutics for this debilitating disease. Further, the control of both inflammation and bone damage is essential for effective management of arthritis. The aim of our study was to evaluate the efficacy of HLXL against arthritic bone damage in adjuvant arthritis (AA) model of RA. Our results show that HLXL treatment suppressed inflammatory arthritis and reduced bone and cartilage damage in the joints of arthritic Lewis rats. HLXL-induced protection against bone damage was mediated primarily via inhibition of mediators of osteoclastic bone remodeling (e.g., receptor activator of nuclear factor kappa-B ligand; RANKL), skewing of RANKL/osteoprotegerin (OPG) ratio in favor of antiosteoclastic activity, reduction in the number of osteoclasts in the arthrodial joint's bone, and inhibition of cytokine production and MMP activity. Our results suggest that HLXL might offer a promising alternative/adjunct treatment for both inflammation and bone damage in RA.
Rheumatoid arthritis (RA) is a chronic inflammatory disease affecting the joints that can lead to deformities and disability. The prolonged use of conventionally used drugs is associated with severe adverse reactions. Therefore, safer and less expensive therapeutic products are continually being sought. Huo-Luo-Xiao-Ling dan (HLXL), a traditional Chinese herbal mixture, and its modified versions possess anti-arthritic activity. In this paper, we examined the influence of modified HLXL on two of the key mediators of arthritic inflammation and tissue damage, namely, chemokines and matrix-metalloproteinases (MMPs) in the rat adjuvant-induced arthritis (AA) model of RA. We treated arthritic Lewis rats with HLXL (2.3 g/kg) by daily gavage beginning at the onset of AA. The control rats received the vehicle. At the peak phase of AA, rats were sacrificed and their draining lymph node cells (LNC) and spleen adherent cells (SAC) were tested. The HLXL-treated rats showed a significant reduction in the levels of chemokines (RANTES, MCP-1, MIP-1α, and GRO/KC), MMPs (MMP 2 and 9), as well as cytokines (IL-6 and IL-17) that induce them, compared to the control vehicle-treated rats. Thus, HLXL controls arthritis in part by suppressing the mediators of immune pathology, and it might offer a promising alternative/adjunct treatment for RA.
Autoimmune inflammation is a characteristic feature of rheumatoid arthritis (RA) and other autoimmune diseases. In the natural course of human autoimmune diseases, it is rather difficult to pinpoint the precise timing of the initial event that triggers the cascade of pathogenic events that later culminate into clinically overt disease. Therefore, it is a challenge to examine the early preclinical events in these disorders. Animal models are an invaluable resource in this regard. Furthermore, considering the complex nature of the pathogenic immune events in arthritis, microarray analysis offers a versatile tool to define the dynamic patterns of gene expression during the disease course.
In this study, we defined the profiles of gene expression at different phases of adjuvant arthritis (AA) in Lewis rats and compared them with those of antigen mycobacterial heat shock protein 65 (Bhsp65)-tolerized syngeneic rats. Purified total RNA (100 ng) extracted from the draining lymph node cells was used to generate biotin-labeled fragment cRNA, which was then hybridized with an oligonucleotide-based DNA microarray chip. Significance analysis of microarrays was used to compare gene expression levels between the two different groups by limiting the false discovery rate to < 5%. Some of the data were further analyzed using a fold change ≥2.0 as the cutoff. The gene expression of select genes was validated by quantitative real-time PCR.
Intriguingly, the most dramatic changes in gene expression in the draining lymphoid tissue ex vivo were observed at the preclinical (incubation) phase of the disease. The affected genes represented many of the known proteins that participate in the cellular immune response. Interestingly, the preclinical gene expression profile was significantly altered by a disease-modulating, antigen-based tolerogenic regimen. The changes mostly included upregulation of several genes, suggesting that immune tolerance suppressed disease by activating disease-regulating pathways. We identified a molecular signature comprising at least 12 arthritis-related genes altered by Bhsp65-induced tolerance.
This is the first report of microarray analysis in the rat AA model. The results of this study not only advance our understanding of the early phase events in autoimmune arthritis but also help in identifying potential targets for the immunomodulation of RA.
adjuvant arthritis; gene expression; heat shock proteins; immune tolerance; microarray analysis
Eleven authenticated botanicals used in the traditional Chinese medicine Huo-Luo-Xiao-Ling Dan were screened for ligands to cyclooxygenase (COX) using pulsed ultrafiltration liquid chromatography-mass spectrometry, and a mass spectrometry-based enzyme assay was used to determine the concentration of each of 17 ligands that inhibited COX-1 or COX-2 by 50% (IC50). Acetyl-11-keto-β-boswellic -boswellic acid, acid, acetyl-α-boswellic acid, acetyl-β-boswellic acid, and betulinic acid were COX-1 selective inhibitors with IC50 values of approximately 10 μM. Senkyunolide O and cryptotanshinone were COX-2 selective inhibitors with IC50 values of 5 and 22 μM, respectively. Roburic acid and phenethyl-trans-ferulate inhibited COX-1 and COX-2 equally. COX inhibition and the IC50 values of most of these natural product ligands have not been reported previously.
Cyclooxygenase; COX-2; drug discovery; botanical dietary supplements; senkyunolide O; cryptotanshinone
Rheumatoid arthritis (RA) is one of the major autoimmune diseases of global prevalence. The use of the anti-inflammatory drugs for the treatment of RA is associated with severe adverse reactions and toxicity. This limitation has necessitated the search for novel therapeutic products. We report here a traditional Chinese medicine-based herbal formula, Huo luo xiao ling dan (HLXL), which has potent antiarthritic activity as validated in the rat adjuvant-induced arthritis (AA) model. HLXL (2.3 g/Kg) was fed to Lewis (RT.11) rats daily by gavage beginning at the onset of arthritis and then continued through the observation period. HLXL inhibited the severity of ongoing AA. This suppression of arthritis was associated with significant alterations in the T cell proliferative and cytokine responses as well as the antibody response against the disease-related antigen, mycobacterial heat-shock protein 65 (Bhsp65). There was a reduction in the level of the proinflammatory cytokines IL-17 and IL-1β but enhancement of the anti-inflammatory cytokine IL-10 level. In addition, there was inhibition of both the anti-Bhsp65 antibody response and the serum level of nitric oxide. Thus, HLXL is a promising CAM modality for further testing in RA patients.
HLXL is a traditional Chinese medicine that has long been used in folk medicine for the treatment of chronic inflammatory diseases. However, the precise immunological mechanisms by which HLXL mediates its anti-inflammatory activity are not fully defined.
Aim of the study
To determine the effects of HLXL on antigen-specific immune parameters in adjuvant-induced inflammation model in the Lewis rat.
Materials and Methods
Rats were fed daily with either HLXL (2.3 g/kg) or vehicle (water) beginning 3 d before subcutaneous injection of heat-killed M. tuberculosis H37Ra (Mtb), and then continued for another 6 d. After 9 d of Mtb injection, the draining lymph node cells were tested for T cell proliferative and cytokine responses against mycobacterial heat-shock protein 65 (Bhsp65). Moreover, sera were tested for anti-Bhsp65 antibodies and nitric oxide (NO).
HLXL-treated rats showed reduced T cell proliferative response to Bhsp65 compared to control rats. Furthermore, HLXL suppressed IL-17 response but enhanced IL-10 response without much effect on IFN-γ. HLXL treatment also reduced the levels of anti-Bhsp65 antibodies but not that of NO.
HLXL feeding modulated both the cellular and the humoral immune response to Bhsp65 favoring an anti-inflammatory milieu for suppression of adjuvant-induced inflammation.
Huo-Luo-Xiao-Ling Dan; Immune modulation; Cytokines; Antibodies; T cells; Inflammation
The herbal formula Huo Luo Xiao Ling Dan (HLXL) and its modifications have been used in traditional Chinese medicine for about one hundred years to alleviate pain and inflammation.
To investigate the effects of HLXL on complete Freund’s adjuvant (CFA)-induced multiple-joint arthritis in rats.
Materials and Methods
Male Lewis rats, 190–210g, were immunized subcutaneously at the base of the tail with 200 µl of heat-killed M. tuberculosis in mineral oil (5 mg/ml). HLXL (2.30g/kg and 4.60g/kg) or vehicle control (n=8 per group) was administered orally (i.g.) once a day between days 16–25 post-CFA injection. The rats were observed for signs of arthritis with arthritic changes (erythema, edema, induration) being scored on a scale of 0 to 4 of increasing severity using a standard scoring system. The maximum arthritis score per rat was 16. A plethysmometer was used to measure edema volume in each paw. Adverse effects of HLXL were monitored by closely observing the animals for unusual behavioral changes. Levels of tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) in local tissue were measured by enzyme-linked immunosorbent assay on day 25 post-CFA.
HLXL significantly decreased arthritis scores between days 23–25 in the 2.30g/kg group and 21–25 in the 4.60g/kg group (p<0.05). It reduced paw edema on days 22 and 24 in the 2.30g/kg group and on days 20, 22 and 24 in the 4.60g/kg group compared to control (p<0.05). Local tissue TNF-α and IL-1β levels on day 25 post-CFA injection were significantly (p<0.05) lower in rats treated with HLXL than in control rats. No observable adverse effects were found.
The data suggest that HLXL produces significant anti-arthritic effects that may be mediated by suppressing pro-inflammatory cytokines, and it appears to be safe.
Arthritis; Chinese Herbs; IL-1β; TNF-α; Rats