Jararhagin-induced mechanical hyperalgesia depends on TNF-α, IL-1β and NFκB in mice

Photobiomodulation mitigates Bothrops jararacussu venom-induced damage in myoblast cells by enhancing myogenic factors and reducing cytokine production

BACKGROUND

Photobiomodulation has exhibited promise in mitigating the local effects induced by Bothrops snakebite envenoming; however, the mechanisms underlying this protection are not yet fully understood. Herein, the effectiveness of photobiomodulation effects on regenerative response of C2C12 myoblast cells following exposure to Bothrops jararacussu venom (BjsuV), as well as the mechanisms involved was investigated.

METHODOLOGY/PRINCIPAL FINDINGS

C2C12 myoblast cells were exposed to BjsuV (12.5 μg/mL) and irradiated once for 10 seconds with laser light of 660 nm (14.08 mW; 0.04 cm2; 352 mW/cm2) or 780 nm (17.6 mW; 0.04 cm2; 440 mW/ cm2) to provide energy densities of 3.52 and 4.4 J/cm2, and total energies of 0.1408 and 0.176 J, respectively. Cell migration was assessed through a wound-healing assay. The expression of MAPK p38-α, NF-Кβ, Myf5, Pax-7, MyoD, and myogenin proteins were assessed by western blotting analysis. In addition, interleukin IL1-β, IL-6, TNF-alfa and IL-10 levels were measured in the supernatant by ELISA. The PBM applied to C2C12 cells exposed to BjsuV promoted cell migration, increase the expression of myogenic factors (Pax7, MyF5, MyoD and myogenin), reduced the levels of proinflammatory cytokines, IL1-β, IL-6, TNF-alfa, and increased the levels of anti-inflammatory cytokine IL-10. In addition, PBM downregulates the expression of NF-kB, and had no effect on p38 MAKP.

CONCLUSION/SIGNIFICANCE

These data demonstrated that protection of the muscle cell by PBM seems to be related to the increase of myogenic factors as well as the modulation of inflammatory mediators. PBM therapy may offer a new therapeutic strategy to address the local effects of snakebite envenoming by promoting muscle regeneration and reducing the inflammatory process.

Molecular Aspects Involved in the Mechanisms of Bothrops jararaca Venom-Induced Hyperalgesia: Participation of NK1 Receptor and Glial Cells

Accidents caused by Bothrops jararaca (Bj) snakes result in several local and systemic manifestations, with pain being a fundamental characteristic. The inflammatory process responsible for hyperalgesia induced by Bj venom (Bjv) has been studied; however, the specific roles played by the peripheral and central nervous systems in this phenomenon remain unclear. To clarify this, we induced hyperalgesia in rats using Bjv and collected tissues from dorsal root ganglia (DRGs) and spinal cord (SC) at 2 and 4 h post-induction. Samples were labeled for Iba-1 (macrophage and microglia), GFAP (satellite cells and astrocytes), EGR1 (neurons), and NK1 receptors. Additionally, we investigated the impact of minocycline, an inhibitor of microglia, and GR82334 antagonist on Bjv-induced hyperalgesia. Our findings reveal an increase in Iba1 in DRG at 2 h and EGR1 at 4 h. In the SC, markers for microglia, astrocytes, neurons, and NK1 receptors exhibited increased expression after 2 h, with EGR1 continuing to rise at 4 h. Minocycline and GR82334 inhibited venom-induced hyperalgesia, highlighting the crucial roles of microglia and NK1 receptors in this phenomenon. Our results suggest that the hyperalgesic effects of Bjv involve the participation of microglial and astrocytic cells, in addition to the activation of NK1 receptors.

Altered RNome expression in Murine Gastrocnemius Muscle following Exposure to Jararhagin, a Metalloproteinase from Bothrops jararaca Venom

Small RNAs (sRNAs) and microRNAs (miRNAs) are small endogenous noncoding single-stranded RNAs that regulate gene expression in eukaryotes. Experiments in mice and humans have revealed that a typical small RNA can affect the expression of a wide range of genes, implying that small RNAs function as global regulators. Here, we used small RNA deep sequencing to investigate how jararhagin, a metalloproteinase toxin produced from the venom of Bothrops jararaca, affected mmu-miRNAs expression in mice 2 hours (Jar 2hrs) and 24 hours (Jar 24hrs) after injection compared to PBS control. The findings revealed that seven mmu-miRNAs were substantially differentially expressed (p value (p (Corr) cut-off 0.05, fold change ≥ 2) at 2 hrs after jararhagin exposure and that the majority of them were upregulated when compared to PBS. In contrast to these findings, a comparison of Jar 24hrs vs. PBS 24hrs demonstrated that the majority of identified mmu-miRNAs were downregulated. Furthermore, the studies demonstrated that mmu-miRNAs can target the expression of several genes involved in the MAPK signaling pathway. The steady antithetical regulation of mmu-miRNAs may correlate with the expression of genes that trigger apoptosis via MAPK in the early stages, and this effect intensifies with time. The findings expand our understanding of the effects of jararhagin on local tissue lesions at the molecular level.

The Bioflavonoids Rutin and Rutin Succinate Neutralize the Toxins of B. jararaca Venom and Inhibit its Lethality

The venom of the Brazilian pit viper Bothrops jararaca (BjV) is a complex mixture of molecules, and snake venom metalloproteinases (SVMP) and serine proteinases (SVSP) are the most abundant protein families found therein. Toxins present in BjV trigger most of the deleterious disturbances in hemostasis observed in snakebites, i.e., thrombocytopenia, hypofibrinogenemia and bleedings. The treatment of patients bitten by snakes still poses challenges and the bioflavonoid rutin has already been shown to improve hemostasis in an experimental model of snakebite envenomation. However, rutin is poorly soluble in water; in this study, it was succinylated to generate its water-soluble form, rutin succinate (RS), which was analyzed comparatively regarding the chemical structure and characteristic features of rutin. Biological activities of rutin and RS were compared on hemostatic parameters, and against toxic activities of crude BjV in vitro. In vivo, C57BL/6 mice were injected i.p. with either BjV alone or pre-incubated with rutin, RS or 1,10-phenanthroline (o-phe, an SVMP inhibitor), and the survival rates and hemostatic parameters were analyzed 48 h after envenomation. RS showed the characteristic activities described for rutin - i.e., antioxidant and inhibitor of protein disulfide isomerase - but also prolonged the clotting time of fibrinogen and plasma in vitro. Differently from rutin, RS inhibited typical proteolytic activities of SVMP, as well as the coagulant activity of BjV. Importantly, both rutin and RS completely abrogated the lethal activity of BjV, in the same degree as o-phe. BjV induced hemorrhages, falls in RBC counts, thrombocytopenia and hypofibrinogenemia in mice. Rutin and RS also improved the recovery of platelet counts and fibrinogen levels, and the development of hemorrhages was totally blocked in mice injected with BjV incubated with RS. In conclusion, RS has anticoagulant properties and is a novel SVMP inhibitor. Rutin and RS showed different mechanisms of action on hemostasis. Only RS inhibited directly BjV biological activities, even though both flavonoids neutralized B. jararaca toxicity in vivo. Our results showed clearly that rutin and RS show a great potential to be used as therapeutic compounds for snakebite envenomation.

Pain modulated by Bothrops snake venoms: Mechanisms of nociceptive signaling and therapeutic perspectives

Snake venoms are substances mostly composed by proteins and peptides with high biological activity. Local and systemic effects culminate in clinical manifestations induced by these substances. Pain is the most uncomfortable condition, but it has not been well investigated. This review discusses Bothrops snakebite-induced nociception, highlighting molecules involved in the mediation of this process and perspectives in treatment of pain induced by Bothrops snake venoms (B. alternatus, B. asper, B. atrox, B. insularis, B. jararaca, B. pirajai, B. jararacussu, B. lanceolatus, B. leucurus, B. mattogrossensis, B. moojeni). We highlight, the understanding of the nociceptive signaling, especially in snakebite, enables more efficient treatment approaches. Finally, future perspectives for pain treatment concerning snakebite patients are discussed.

Peripheral mechanisms involved in Tityus bahiensis venom-induced pain

Scorpionism is a public health burden in Brazil. Tityus bahiensis is responsible for most accidents in the Southeastern region of Brazil. Here, the hyperalgesic mechanisms of Tityus bahiensis venom were investigated, focusing on the role of pro-inflammatory cytokines (tumor necrosis factor alpha [TNF-α] and interleukin 1 beta [IL-1β]) and activation of the transcription factor NFκB. Intraplantar (i.pl.) administration of Tityus bahiensis venom (0.2, 0.6, 1.2 and 2.4 μg/20 μL i.pl.) induced mechanical hyperalgesia and thermal hyperalgesia. The 2.4 μg dose of Tityus bahiensis venom induced overt pain-like behavior and increased myeloperoxidase (MPO) and N-acetyl-beta-D-glucosaminidase (NAG) activities, TNF-α and IL-1β levels in the paw tissue. Systemic pre-treatment with etanercept (soluble TNF-α receptor; 10 mg/kg), IL-1ra (IL-1 receptor antagonist; 30 mg/kg) and pyrrolidine dithiocarbamate (PDTC, nuclear factor kappa B [NFκB] inhibitor; 100 mg/kg) inhibited Tityus bahiensis venom-induced mechanical and thermal hyperalgesia, MPO and NAG activity and overt pain-like behavior. These data demonstrate the involvement of TNF-α and IL-1β signaling as well as NFκB activation in Tityus bahiensis venom-induced mechanical and thermal hyperalgesia, overt pain-like behavior, and MPO activity and NAG activity, indicating thus, that targeting these mechanisms might contribute to reducing the pain in this scorpionism.

Jararhagin, a snake venom metalloproteinase, induces mechanical hyperalgesia in mice with the neuroinflammatory contribution of spinal cord microglia and astrocytes

Jararhagin is a hyperalgesic metalloproteinase from Bothrops jararaca venom. In rodents, jararhagin induces nociceptive behaviors that correlate with an increase in peripheral cytokine levels. However, the role of the spinal cord glia in pain processing after peripheral stimulus of jararhagin has not been investigated. Aiming to explore this proposal, mice received intraplantar (i.pl.) injection of jararhagin and the following parameters were evaluated: hyperalgesia, spinal cord TNF-α, IL-1β levels, and CX3CR1, GFAP and p-NFκB activation. The effects of intrathecal (i.t.) injection of TNF-α soluble receptor (etanercept), IL-1 receptor antagonist (IL-1Ra), and inhibitors of NFκB (PDTC), microglia (minocycline) and astrocytes (α-aminoadipate) were investigated. Jararhagin inoculation induced cytokine production (TNF-α and IL-1β) in the spinal cord, which was reduced by treatment with PDTC (40% and 50%, respectively). Jararhagin mechanical hyperalgesia and cytokine production were inhibited by treatment with etanercept (67%), IL-1Ra (60%), PDTC (70%), minocycline (60%) and α-aminoadipate (45%). Furthermore, jararhagin induced an increase in p-NFκB, CX3CR1 and GFAP detection in the spinal cord indicating activation of NFκB, microglia and astrocytes. These results demonstrate for the first time that jararhagin-induced mechanical hyperalgesia is dependent on spinal cord activation of glial cells, consequent NFκB activation, and cytokine production in mice.

Inflammatory mediators in the pronociceptive effects induced by Bothrops leucurus snake venom: The role of biogenic amines, nitric oxide, and eicosanoids

Bothrops leucurus is the major causative agent of venomous snakebites in Northeastern Brazil. Severe pain is the most frequent symptom in these envenomings, with an important inflammatory component. This work characterized the pronociceptive effects evoked by B. leucurus venom (BLV) in mice and the role of inflammatory mediators in these responses. The nociceptive behaviors were quantified by the modified formalin test. The mechanical hyperalgesia was assessed by the digital von Frey test. Pharmacological assays were performed with different antagonists and synthesis inhibitors to investigate the involvement of inflammatory mediators in both nociceptive events. BLV (1-15 μg/paw) injection in mice evoked intense and dose-dependent nociceptive behaviors that lasted for up to 1 h. BLV (10 μg/paw) also caused sustained mechanical hyperalgesia. Histamine and serotonin played a role in the nociception, but not in the BLV-induced mechanical hyperalgesia. Nitric oxide contributed to both responses, but only to the late stages of mechanical hyperalgesia. Eicosanoids were also present in both nociceptive responses. Prostanoid synthesis by COX-1 seemed to be more relevant for the nociception, whereas COX-2 had a more prominent role in the mechanical hyperalgesia. Leukotrienes were the most relevant mediators of BLV-induced mechanical hyperalgesia, hence inhibiting lipoxygenase pathway could be an efficient therapeutic strategy for pain management during envenoming. Our behavioral data demonstrates that BLV promotes nociceptive transmission mediated by biogenic amines, nitric oxide and eicosanoids, and nociceptor sensitization through nitric oxide and eicosanoids. Moreover, phospholipases A₂ (PLA₂), an important class of toxins present in bothropic venoms, appear to play an important role in the nociceptive and hypernociceptive response induced by BLV.

Antioxidant and anti-inflammatory effects of hesperidin methyl chalcone in experimental ulcerative colitis

Neutrophil infiltration, pro-inflammatory cytokines, and reactive oxygen species (ROS) production have been implicated in development and progression of ulcerative colitis (UC), an inflammatory bowel disease (IBD) characterized by ulcerating inflammation of the mucosal layer generally restricted to the colon. The side effects, safety and human intolerance are limitations of the currently approved treatments for UC. Hesperidin methyl chalcone (HMC) is a flavonoid used to treat chronic venous disease, which shows anti-inflammatory, analgesic, and antioxidant properties in pre-clinical studies, however, its effects on colitis have never been described. Therefore, we aimed to evaluate the protective effects of HMC in a mouse model of acetic acid-induced colitis. Treatment with HMC significantly reduced neutrophil infiltration, edema, colon shortening, macro and microscopic damages induced by intracolonic administration of acetic acid. The improvement of colitis after HMC treatment is related to the increase in colon antioxidant status, and the inhibition of pro-inflammatory cytokines TNF-α, IL-6, IL-1β, and IL-33 in the colon. We observed, moreover, that HMC inhibited NF-κB activation in the colon, which might explain the reduction of the cytokines we observed. Finally, these results demonstrate a novel applicability of HMC to increase antioxidant response and reduce inflammation during acetic acid-induced colitis suggesting it as a promising therapeutic approach for the treatment of ulcerative colitis.

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

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

The granulopoietic cytokine granulocyte colony-stimulating factor (G-CSF) induces pain: analgesia by rutin

Rutin is a glycone form of the flavonol quercetin and it reduces inflammatory pain in animal models. Therapy with granulocyte colony-stimulating factor (G-CSF) is known by the pain caused as its main side effect. The effect of rutin and its mechanisms of action were evaluated in a model of hyperalgesia induced by G-CSF in mice. The mechanical hyperalgesia induced by G-CSF was reduced by treatment with rutin in a dose-dependent manner. Treatment with both rutin + morphine or rutin + indomethacin, at doses that are ineffectual per se, significantly reduced the pain caused by G-CSF. The nitric oxide (NO)-cyclic guanosine monophosphate (cGMP)-protein kinase G (PKG)-ATP-sensitive potassium channel (K_ATP) signaling pathway activation is one of the analgesic mechanisms of rutin. Rutin also reduced the pro-hyperalgesic and increased anti-hyperalgesic cytokine production induced by G-CSF. Furthermore, rutin inhibited the activation of the nuclear factor kappa-light-chain enhancer of activated B cells (NFκB), which might explain the inhibition of the cytokine production. Treatment with rutin upregulated the decreased mRNA expression of the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) combined with enhancement of the mRNA expression of the Nrf2 downstream target heme oxygenase (HO-1). Intraperitoneal (i.p.) treatment with rutin did not alter the mobilization of neutrophils induced by G-CSF. The analgesia by rutin can be explained by: NO-cGMP-PKG-K_ATP channel signaling activation, inhibition of NFκB and triggering the Nrf2/HO-1 pathway. The present study demonstrates rutin as a promising pharmacological approach to treat the pain induced by G-CSF without impairing its primary therapeutic benefit of mobilizing hematopoietic progenitor cells into the blood.

The kiss of (cell) death: can venom-induced immune response contribute to dermal necrosis following arthropod envenomations?

Introduction: Snakes, insects, arachnids and myriapods have been linked to necrosis following envenomation. However, the pathways involved in arthropod venom-induced necrosis remain a highly controversial topic among toxinologists, clinicians and the public. On the one hand, clinicians report on alleged envenomations based on symptoms and the victims' information. On the other hand, toxinologists and zoologists argue that symptoms are incompatible with the known venom activity of target species. This review draws from the literature on arthropod envenomations, snakebite, and inflammatory processes to suggest that envenomation by a range of organisms might trigger an intense inflammatory cascade that ultimately lead to necrosis. If confirmed, these processes would have important implications for the treatment of venom-induced necrosis. Objectives: To describe two inflammatory pathways of regulated necrosis, tumour necrosis factor (necroptosis) and Neutrophil Extracellular Traps (NETosis); to discuss existing knowledge about snake venom and arachnid-induced necrosis demonstrating the involvement of tumour necrosis factor and neutrophils in the development of tissue necrosis following envenomation and to contribute to the understanding of venom-induced necrosis by arthropods and provide clinicians with an insight into little known inflammatory processes which may occur post envenomation. Methods: ISI Web of Science databases were searched using the terms "spider bite necrosis", "arthropod envenomation necrosis", "venom necrosis", "venom immune response", "loxoscelism", "arachnidism", "necroptosis venom", "necroptosis dermatitis", "tumour necrosis factor TNF venom", "scorpionism", "scolopendrism", "centipede necrosis", "NETosis venom", "NETosis necrosis". Searches produced 1737 non-duplicate citations of which 74 were considered relevant to this manuscript. Non-peer-reviewed sources or absence of voucher material identifying the organism were excluded. What is necrosis? Necrosis is the breakdown of cell membrane integrity followed by inflowing extracellular fluid, organelle swelling and the release of proteolytic enzymes into the cytosol. Necrosis was historically considered an unregulated process; however, recent studies demonstrate that necrosis can also be a programmed event resulting from a controlled immune response (necroptosis). Tumour necrosis factor and the necroptosis pathway: Tumour necrosis factor is a pro-inflammatory cytokine involved in regulating immune response, inflammation and cell death/survival. The pro-inflammatory cytokine TNF-α participates in the development of necrosis after envenomation by vipers. Treatment with TNF-α-antibodies may significantly reduce the manifestation of necrosis. Neutrophil Extracellular Traps and the NETosis pathway: The process by which neutrophils discharge a mesh of DNA strands in the extracellular matrix to entangle ("trap") pathogens, preventing them from disseminating. Neutrophil Extracellular Traps have been recently described as important in venom-induced necrosis. Trapped venom accumulates at the bite site, resulting in significant localized necrosis. Arthropod venom driving necrosis: Insects, myriapods and arachnids can induce necrosis following envenomation. So far, the processes involved have only been investigated in two arachnids: Loxosceles spp. (recluse spiders) and Hemiscorpius lepturus (scorpion). Loxosceles venom contains phospholipases D which hydrolyse sphingomyelin, resulting in lysis of muscle fibers. Subsequently liberated ceramides act as intermediaries that regulate TNF-α and recruit neutrophils. Experiments show that immune-deficient mice injected with Loxosceles venom experience less venom-induced inflammatory response and survive longer than control mice. Necrosis following Hemiscorpius lepturus stings correlates with elevated concentrations of TNF-α. These observations suggest that necrosis may be indirectly triggered or worsened by pathways of regulated necrosis in addition to necrotic venom compounds. Conclusions: Envenomation often induce an intense inflammatory cascade, which under certain circumstances may produce necrotic lesions independently from direct venom activity. This could explain the inconsistent and circumstantial occurrence of necrosis following envenomation by a range of organisms. Future research should focus on identifying pathways to regulated necrosis following envenomation and determining more efficient ways to manage inflammation. We suggest that clinicians should consider the victim's immune response as an integral part of the envenomation syndrome.

Inflammation, angiogenesis and fibrogenesis are differentially modulated by distinct domains of the snake venom metalloproteinase jararhagin

Jararhagin, a metalloprotease from Bothrops jararaca snake venom, is a toxin containing the metalloproteinase, disintegrin-like and cysteine-rich domains; it causes acute inflammation and damage to vascular tissue. However, the actions of these domains on key components of chronic inflammation have not been determined. Our aim was to investigate the effects of jararhagin (Jar), jararhagin-C (Jar-C) and o-phenantrolin-treated jararhagin (Jar-Phe), on inflammatory response, blood vessel formation and extracellular matrix deposition in the murine sponge model. The polyether-polyurethane sponge matrix was implanted into Balb/c mice and injected daily with Jar (400 ng), Jar-Phe (400 ng), Jar-C (200 ng) or saline (control). Nine days after implantation, the sponge discs were removed and processed. In the Jar-treated implants, some of inflammatory markers (N-acetyl-β-d-glucosaminidase activity, CCL2 and TNF-α) and TGF-β1 levels were higher compared with the control group. In the Jar-C group, the inflammatory markers myeloperoxidase activity and CXCL1 were higher compared with the control. In this group, VEGF levels and collagen deposition were also higher. Jar-Phe treatment was able to inhibit the activity and/or production of MPO, CXCL1, CCL2 and TGF-β. The differential effects of these proteins in modulating the main components of fibrovascular tissue may be exploited in the management fibroproliferative diseases.

Recent development in antihyperalgesic effect of phytochemicals: anti-inflammatory and neuro-modulatory actions

INTRODUCTION

Pain is an unpleasant sensation triggered by noxious stimulation. It is one of the most prevalent conditions, limiting productivity and diminishing quality of life. Non steroidal anti inflammatory drugs (NSAIDs) are widely used as pain relievers in present day practice as pain is mostly initiated due to inflammation. However, due to potentially serious side effects, long term use of these antihyperalgesic drugs raises concern. Therefore there is a demand to search novel medicines with least side effects. Herbal products have been used for centuries to reduce pain and inflammation, and phytochemicals are known to cause fewer side effects. However, identification of active phytochemicals of herbal medicines and clear understanding of the molecular mechanism of their action is needed for clinical acceptance.

MATERIALS AND METHODS

In this review, we have briefly discussed the cellular and molecular changes during hyperalgesia via inflammatory mediators and neuro-modulatory action involved therein. The review includes 54 recently reported phytochemicals with antihyperalgesic action, as per the literature available with PubMed, Google Scholar and Scopus.

CONCLUSION

Compounds of high interest as potential antihyperalgesic agents are: curcumin, resveratrol, capsaicin, quercetin, eugenol, naringenin and epigallocatechin gallate (EGCG). Current knowledge about molecular targets of pain and their regulation by these phytochemicals is elaborated and the scope of further research is discussed.

A Traditional Chinese Medicine Xiao-Ai-Tong Suppresses Pain through Modulation of Cytokines and Prevents Adverse Reactions of Morphine Treatment in Bone Cancer Pain Patients

Treating cancer pain continues to possess a major challenge. Here, we report that a traditional Chinese medicine Xiao-Ai-Tong (XAT) can effectively suppress pain and adverse reactions following morphine treatment in patients with bone cancer pain. Visual Analogue Scale (VAS) and Quality of Life Questionnaire (EORTC QLQ-C30) were used for patient's self-evaluation of pain intensity and evaluating changes of adverse reactions including constipation, nausea, fatigue, and anorexia, respectively, before and after treatment prescriptions. The clinical trials showed that repetitive oral administration of XAT (200 mL, bid, for 7 consecutive days) alone greatly reduced cancer pain. Repetitive treatment with a combination of XAT and morphine (20 mg and 30 mg, resp.) produced significant synergistic analgesic effects. Meanwhile, XAT greatly reduced the adverse reactions associated with cancer and/or morphine treatment. In addition, XAT treatment significantly reduced the proinflammatory cytokines interleukin-1β and tumor necrosis factor-α and increased the endogenous anti-inflammatory cytokine interleukin-10 in blood. These findings demonstrate that XAT can effectively reduce bone cancer pain probably mediated by the cytokine mechanisms, facilitate analgesic effect of morphine, and prevent or reduce the associated adverse reactions, supporting a use of XAT, alone or with morphine, in treating bone cancer pain in clinic.