The bee venom test: a new tonic-pain test

Melittin protein inhibits the proliferation of MG63 cells by activating inositol-requiring protein-1α and X-box binding protein 1-mediated apoptosis

The aim of the present study was to explore the pro-apoptotic effect and specific mechanism of action of melittin (MEL) in humans. The effects of MEL on apoptosis in osteosarcoma and fetal osteoblast cells were investigated, and the mechanism that induced MG63 cell growth was also explored. The effects of MEL on cell proliferation were detected by a 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide analysis. Apoptosis was detected by flow cytometric analysis. MEL protein, inositol-requiring protein-1 (IRE-α), phosphorylated-protein kinase R-like endoplasmic reticulum (ER) kinase, spliced X-box-1 (XBP1), eukaryotic translation initiation factor-2α, cleaved activating transcription factor-6, caspase-12 and C/EBP homology protein (CHOP) were detected in three groups and two cell lines by western blot analysis. The results indicated that the expression or incubation of MEL in the MG63 cells triggered apoptosis and the inhibition of proliferation. One protein from the ER stress unfolded protein response pathway, IRE-α, was involved in the MEL-induced apoptosis in MG63 cells. Furthermore, spliced XBP1 protein was significantly increased in the MEL peptide incubated and MEL expressing groups of MG63 cells. Furthermore, CHOP protein expression was activated in MG63 cells following being incubated with or expressing MEL. In conclusion, MEL serves as an effective factor that inhibits the proliferation of MG63 cells via activating the ER stress-mediated apoptosis pathway. This activation is triggered by the IRE-α pathway mediated by inducing CHOP protein expression.

Spatial and temporal plasticity of synaptic organization in anterior cingulate cortex following peripheral inflammatory pain: multi-electrode array recordings in rats

To explore whether experiencing inflammatory pain has an impact upon intracortical synaptic organization, the planar multi-electrode array (MEA) technique and 2-dimensional current source density (2D-CSD) imaging were used in slice preparations of the anterior cingulate cortex (ACC) from rats. Synaptic activity across different layers of the ACC was evoked by deep layer stimulation through one electrode. The layer-localization of both local field potentials (LFPs) and the spread of current sink calculated by 2D-CSD analysis was characterized pharmacologically. Moreover, the induction of long-term potentiation (LTP) and changes in LTP magnitude were also evaluated. We found that under naïve conditions, the current sink was initially generated in layer VI, then spread to layer V and finally confined to layers II-III. This spatial pattern of current sink movement typically reflected changes in depolarized sites from deep layers (V-VI) to superficial layers (II-III) where intra- and extracortical inputs terminate. In the ACC slices from rats in an inflamed state (for 2 h) caused by intraplantar bee-venom injection, the spatial profile of intra-ACC synaptic organization was significantly changed, showing an enlarged current sink distribution and a leftward shift of the stimulus-response curves relative to the naïve and saline controls. The change was more distinct in the superficial layers (II-III) than in the deep site. In terms of temporal properties, the rate of LTP induction was significantly increased in layers II-III by inflammatory pain. However, the magnitude of LTP was not significantly enhanced by this treatment. Taken together, these results show that inflammatory pain results in distinct spatial and temporal plasticity of synaptic organization in the ACC, which may lead to altered synaptic transmission and modulation.

The mTOR signaling pathway regulates pain-related synaptic plasticity in rat entorhinal-hippocampal pathways

Background

Our previous work demonstrated that persistent peripheral nociception (PPN) leads to synaptic plasticity and functional changes in the rat hippocampus. The protein kinase mTOR is a critical regulator of protein synthesis-dependent synaptic plasticity in the hippocampus as well as synaptic plasticity associated with central and peripheral pain sensitization. We examined the role of mTOR signaling in pain-associated entorhinal cortex (EC) - hippocampal synaptic plasticity to reveal possible cellular mechanisms underlying the effects of chronic pain on cognition and emotion.

Results

Subcutaneous injection of bee venom (BV) into one hind paw to induce PPN resulted in sustained (> 8 h) mTOR phospho-activation and enhanced phosphorylation of the mTOR target p70 S6 kinase (S6K) in the hippocampus. The magnitude and duration of long-term potentiation (LTP) in both EC - dentate gyrus (DG) and EC - CA1 synaptic pathways were elevated in BV-treated rats as measured by microelectrode array recording. Moreover, the number of potentiated synapses in the hippocampus was markedly upregulated by BV-induced PPN. Both elevated mTOR-S6K signaling and enhanced LTP induced by BV injection were reversed by systemic injection of the mTOR inhibitor rapamycin (RAPA). Rats injected with BV exhibited markedly reduced ambulation and exploratory activity in the open field (signs of depression and anxiety) compared to controls, and these effects were also reversed by RAPA.

Conclusion

We suggest that PPN-induced enhancement of synaptic plasticity in EC - hippocampal pathways and the behavioral effects of PPN are dependent on mTOR-S6K signaling.

Neonatal bee venom exposure induces sensory modality-specific enhancement of nociceptive response in adult rats

OBJECTIVE

Previous studies have shown that inflammatory pain at the neonatal stage can produce long-term structural and functional changes in nociceptive pathways, resulting in altered pain perception in adulthood. However, the exact pattern of altered nociceptive response and associated neurochemical changes in the spinal cord in this process is unclear.

METHOD

In this study, we used an experimental paradigm in which each rat first received intraplantar bee venom (BV) or saline injection on postnatal day 1, 4, 7, 14, 21, or 28. This was followed 2 months later by a second intraplantar bee venom injection in the same rats to examine the difference in nociceptive responses.

RESULTS

We found that neonatal inflammatory pain induced by the first BV injection significantly reduced baseline paw withdrawal mechanical threshold, but not baseline paw withdrawal thermal latency, when rats were examined 2 months from the first BV injection. Neonatal inflammatory pain also exacerbated mechanical, but not thermal, hyperalgesia in response to the second BV injection in these same rats. Rats exposed to neonatal inflammation also showed up-regulation of spinal NGF, TrkA receptor, BDNF, TrkB receptor, IL-1β, and COX-2 expression following the second BV injection, especially with prior BV exposure on postnatal day 21 or 28.

CONCLUSION

These results indicate that neonatal inflammation produces sensory modality-specific changes in nociceptive behavior and alters neurochemistry in the spinal cord of adult rats. These results also suggest that a prior history of inflammatory pain during the developmental period might have an impact on clinical pain in highly susceptible adult patients.

Acute Dermal Toxicity Study of Bee Venom (Apis mellifera L.) in Rats

Bee venom (Apis mellifera L. BV) has been used as a cosmetic ingredient for anti-ageing, anti-inflammatory and antibacterial functions. The aim of this study was to evaluate the acute toxicity after a single dermal administration of BV, BV was administered to 2 groups of Sprague-Dawley (SD) male and female rats (5 animals/group) at doses of 0 and 1,500 mg/kg body weight (BW). Mortality, clinical signs, body weight changes and gross findings were continually monitored for 15 days following the single dose. There were no unscheduled deaths in any groups during the study period. No BV related clinical signs and body weight changes were observed in any groups during the study period. There were no abnormal gross findings at necropsy on day 15 after the treatment. On the basis of the above results, it was concluded that there were no treatment-related effect on mortality, clinical signs, body weight changes and gross findings in SD rats treated with a single dermal dose of BV at dose of 1,500 mg/kg BW. Therefore, the approximate lethal dose of BV was considered to be over 1,500 mg/kg/day for both sexes of rats. BV may provide a developmental basis for a cosmetic ingredient or external application for topical uses.

Skin Sensitization Study of Bee Venom (Apis mellifera L.) in Guinea Pigs

Bee venom (Apis mellifera L., BV) has been used as a cosmetic ingredient for antiaging, anti-inflammatory and antibacterial functions. The aim of this study was to access the skin sensitization of BV, a Buehler test was conducted fifty healthy male Hartley guinea pigs with three groups; Group G1 (BVsensitization group, 20 animals), group G2 (the positive control-sensitization group, 20 animals), and group G3 (the ethyl alcohol-sensitization group, 10 animals). The exposure on the left flank for induction was repeated three times at intervals of one week. Two weeks after the last induction, the challenge was performed on the right flank. No treatment-related clinical signs or body weight changes were observed during the study period. The average skin reaction evaluated by erythema and edema on the challenge sites and sensitization rate in the BV-sensitization group at 30 hours were 0.0 and 0%, respectively, which are substantially low compared with in positive control group (average skin reaction: 0.55, sensitization rate: 40%) and identical with in vehicle control group, representing a weak sensitizing potential. The average skin reaction and sensitization rate observed at 54 hours were 0.0 and 0% in the BV-sensitization group, respectively, and 0.25 and 20% in the positive control group, respectively. It was concluded that BV classified to Grade I, induced no sensitization when tested in guinea pigs and may provide a developmental basis for a cosmetic ingredient or external application for topical uses.

Potentiation of a novel palladium (II) complex lethality with bee venom on the human T-cell acute lymphoblastic leukemia cell line (MOLT-4)

Background

Although honeybee venom (BV) has been reported to induce apoptosis in different types of cancerous cells, its synergistic effects with customary anti-cancer drugs remain largely unknown. In the present study, we evaluated the cytotoxic effect of BV alone (as a natural product) and the synergistic cytological effects of this component in combination with [Pd (bpy) (Pi-Pydtc)]NO₃ – a novel palladium complex on human T-cell lymphoblastic leukemia cells. To investigate the cytotoxic effect of the BV alone and in combination with palladium complex on MOLT-4 cells MTT assay was performed. In order to determine the apoptotic effects of BV separately and in combination with Pd (II) complex on these cells and its ability to induce apoptosis, morphological examination, flowcytometric analysis and caspase-3 colorimetric assay were done.

Results

We found that BV induced morphological changes, namely nuclear shrinkage, and inhibited MOLT-4 cell proliferation; both effects were dose- and time-dependent. Flow cytometry by Annexin-V antibody demonstrated that BV induced apoptosis in MOLT-4 cells. Furthermore, BV induced apoptosis independently of caspase-3 in these cells. In addition, we proved a clear synergistic effect of BV on [Pd (bpy) (Pi-Pydtc)]NO₃. The apoptotic pathway activated by BV in combination with Pd complex was caspase-3-dependent.

Conclusions

These observations provide an explanation for the anti-proliferative properties of BV, and suggest that this agent may be useful for treating lymphoblastic leukemia alone or in combination with chemotherapy drugs pending further investigations on animal models as preclinical tests.

Acute stress regulates nociception and inflammatory response induced by bee venom in rats: possible mechanisms

Restraint stress modulates pain and inflammation. The present study was designed to evaluate the effect of acute restraint stress on inflammatory pain induced by subcutaneous injection of bee venom (BV). First, we investigated the effect of 1 h restraint on the spontaneous paw-flinching reflex (SPFR), decrease in paw withdrawal mechanical threshold (PWMT) and increase in paw volume (PV) of the injected paw induced by BV. SPFR was measured immediately after BV injection, and PWMT and PV were measured 2 h before BV and 2-8 h after BV. The results showed that acute restraint inhibited significantly the SPFR but failed to affect mechanical hyperalgesia. In contrast, stress enhanced significantly inflammatory swelling of the injected paw. In a second series of experiments, the effects of pretreatment with capsaicin locally applied to the sciatic nerve, systemic 6-hydroxydopamine (6-OHDA), and systemic naloxone were examined on the antinociception and proinflammation produced by acute restraint stress. Local capsaicin pretreatment inhibited BV-induced nociception and inflammatory edema, and had additive effects with stress on nociception but reduced stress enhancement of edema. Systemic 6-OHDA treatment attenuated the proinflammatory effect of stress, but did not affect the antinociceptive effect. Systemic naloxone pretreatment eliminated the antinociceptive effect of stress, but did not affect proinflammation. Taken together, our data indicate that acute restraint stress contributes to antinociception via activating an endogenous opioid system, while sympathetic postganglionic fibers may contribute to enhanced inflammation in the BV pain model.

Melittin: a lytic peptide with anticancer properties

Melittin (MEL) is a major peptide constituent of bee venom that has been proposed as one of the upcoming possibilities for anticancer therapy. Recent reports point to several mechanisms of MEL cytotoxicity in different types of cancer cells such as cell cycle alterations, effect on proliferation and/or growth inhibition, and induction of apoptotic and necrotic cell death trough several cancer cell death mechanisms, including the activation of caspases and matrix metalloproteinases. Although cytotoxic to a broad spectrum of tumour cells, the peptide is also toxic to normal cells. Therefore its therapeutic potential cannot be achieved without a proper delivery vehicle which could be overcome by MEL nanoparticles that possess the ability to safely deliver significant amount of MEL intravenously, and to target and kill tumours. This review paper summarizes the current knowledge and brings latest research findings on the anticancer potential of this lytic peptide with diverse functions.

Bee Venom Attenuates Experimental Autoimmune Encephalomyelitis through Direct Effets on CD4+CD25+FOXP3+ T Cells

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system that leads to substantial disability through deficits of sensation and of motor, autonomic, and neuro-cognitive function. Many clinical and pathological features of experimental autoimmune encephalomyelitis (EAE) show close similarity to MS. Bee venom (BV) has been used in the practice of oriental medicine and evidence from the literature indicates that BV plays an anti-inflammatory or anti-nociceptive role against inflammatory reactions associated with arthritis and other inflammatory diseases. The purpose of the present study was to determine whether BV could suppress immune cell differentiation and infiltration into spinal cord on EAE mice commonly used as a model for MS. BV treatment increased the population of CD4+CD25+Foxp3+ T cells and inhibited CD4+ T-cell proliferation in vitro. In vivo, BV treatment increased the population of CD4+CD25+Foxp3+ T cells. Furthermore, BV administration reduced the severity of EAE while concurrently decreasing INF-γ producing CD4+T cells, IL-17A producing CD4+T cells and inflammatory cytokine production including INF-γ, IL-17A, TNF and IL-6. BV-treated animals exhibited less infiltration and preserved morphology compared to saline-treated animals. Interestingly, the therapeutic effects of BV on EAE disappeared when CD4+CD25+Foxp3+ T cells were depleted by using anti-CD25 antibody. Our research suggests that BV could be a potential therapeutic agent for antiinflammatory effects in an animal model of EAE.

Effects of a non-selective TRPC channel blocker, SKF-96365, on melittin-induced spontaneous persistent nociception and inflammatory pain hypersensitivity

OBJECTIVE

Melittin is the main peptide in bee venom and causes both persistent spontaneous nociception and pain hypersensitivity. Our recent studies indicated that both transient receptor potential (TRP) vanilloid receptor 1 (TRPV1) and canonical TRPs (TRPCs) are involved in mediating the melittin-induced activation of different subpopulations of primary nociceptive cells. Here, we further determined whether TRPC channels are involved in melittin-induced inflammatory nociceptive responses in behavioral assays.

METHODS

The anti-nociceptive and anti-hyperalgesic effects of localized peripheral administration of three doses of the non-selective TRPC antagonist, SKF-96365 (1-{β-[3-(4-methoxyphenyl)propoxy]-4-methoxyphenyl}-1H-imidazole hydrochloride), were evaluated in melittin tests. Pain-related behaviors were rated by counting the number of paw flinches, and measuring paw withdrawal thermal latency (s) and paw withdrawl mechanical threshold (g), over a 1-h time-course.

RESULTS

Localized peripheral SKF-96365 given before melittin prevented, and given after melittin significantly suppressed, the melittin-evoked persistent spontaneous nociception. Pre-blockade and post-suppression of activation of primary nociceptive activity resulted in decreased hypersensitivity to both thermal and mechanical stimuli applied to the primary injury site of the ipsilateral hindpaw, despite dose-effect differences between thermal and mechanical hyperalgesia. However, local administration of SKF-96365 into the contralateral hindpaw had no significant effect on any pain-associated behaviors. In addition, SKF-96365 had no effect on baseline threshold for either thermal or mechanical sensitivity under normal conditions.

CONCLUSION

Besides TRPV1, SKF-96365-sensitive TRPC channels might also be involved in the pathophysiological processing of melittin-induced inflammatory pain and hypersensitivity. Therapeutically, SKF-96365 is equally effective in preventing primary thermal and mechanical hyperalgesia as well as persistent spontaneous nociception. However, this drug is likely to be more effective in the relief of thermal hyperalgesia than mechanical hyperalgesia when applied 5 min after establishment of primary afferent activation.

Bee venom at different concentrations modulates the aeroallergen-induced activation of nasal polyp epithelial cells

Bee venom (BV) has long been used as an oriental traditional medicine for the control of pain and inflammation. However, BV's anti-inflammatory mechanisms remain unclear. This study aimed to clarify the potential clinical efficacy of BV concerning the anti-inflammatory effect on nasal epithelial cell inflammation. Nasal polyp epithelial cells were obtained from patients. Cells were exposed to Alternaria alternata, Aspergillus nigra, Dermatophagoides pteronyssinus, Dermatophagoides farina and lipopolysaccharide with or without various concentrations of BV. Interleukin (IL)-6, IL-8, and granulocyte macrophage colony-stimulating factor were measured to determine the activation of epithelial cells. Nuclear factor-ĸB (NF-ĸB) and activator protein 1 expression and activity were determined with Western blot analysis and ELISA. Cytotoxicity of BV was measured using a CellTiter-96® aqueous cell proliferation assay kit. Cell survival was significantly decreased at BV concentrations exceeding 5 µg/ml. Fungi-induced cytokine production was more effectively inhibited by BV than house dust mite. Alternaria enhanced NF-ĸB expression, which was strongly inhibited by BV. BV appears to be relatively safe, and is of potential value for the treatment of airway inflammation and/or immunologic diseases.

Bee venom in cancer therapy

Bee venom (BV) (api-toxin) has been widely used in the treatment of some immune-related diseases, as well as in recent times in treatment of tumors. Several cancer cells, including renal, lung, liver, prostate, bladder, and mammary cancer cells as well as leukemia cells, can be targets of bee venom peptides such as melittin and phospholipase A2. The cell cytotoxic effects through the activation of PLA2 by melittin have been suggested to be the critical mechanism for the anti-cancer activity of BV. The induction of apoptotic cell death through several cancer cell death mechanisms, including the activation of caspase and matrix metalloproteinases, is important for the melittin-induced anti-cancer effects. The conjugation of cell lytic peptide (melittin) with hormone receptors and gene therapy carrying melittin can be useful as a novel targeted therapy for some types of cancer, such as prostate and breast cancer. This review summarizes the current knowledge regarding potential of bee venom and its compounds such as melittin to induce cytotoxic, antitumor, immunomodulatory, and apoptotic effects in different tumor cells in vivo or in vitro. The recent applications of melittin in various cancers and a molecular explanation for the antiproliferative properties of bee venom are discussed.

Dermal and Ocular Irritation Studies of Honeybee (Apis mellifera L.) Venom

The aim of this study was to access the irritant properties of bee venom (BV) after its application to skin and eye mucous membranes of the rabbit. The animals were also observed for clinical signs and mortality after the application of the test material. Six animals were used for the skin irritation test and nine rabbits for the eye irritation test. The acute BV application to the rabbit skin revealed no appreciable clinical signs throughout the observation period of 72 h and there was no mortality seen. In the eye irritation test, eye reactions were read and graded 24, 48, 72, 96 and 168 h after BV treatment. No changes in the cornea, iris or conjunctivae were observed at all time points of observations. Based on the present findings, it can be concluded that the irritation potential of BV is negligible.

The Protective Effect of Apamin on LPS/Fat-Induced Atherosclerotic Mice

Apamin, a peptide component of bee venom (BV), has anti-inflammatory properties. However, the molecular mechanisms by which apamin prevents atherosclerosis are not fully understood. We examined the effect of apamin on atherosclerotic mice. Atherosclerotic mice received intraperitoneal (ip) injections of lipopolysaccharide (LPS, 2 mg/kg) to induce atherosclerotic change and were fed an atherogenic diet for 12 weeks. Apamin (0.05 mg/kg) was administered by ip injection. LPS-induced THP-1-derived macrophage inflammation treated with apamin reduced expression of tumor necrosis factor (TNF)-α, vascular cell adhesion molecule (VCAM)-1, and intracellular cell adhesion molecule (ICAM)-1, as well as the nuclear factor kappa B (NF-κB) signaling pathway. Apamin decreased the formation of atherosclerotic lesions as assessed by hematoxylin and elastic staining. Treatment with apamin reduced lipids, Ca(2+) levels, and TNF-α in the serum from atherosclerotic mice. Further, apamin significantly attenuated expression of VCAM-1, ICAM-1, TGF-β1, and fibronectin in the descending aorta from atherosclerotic mice. These results indicate that apamin plays an important role in monocyte/macrophage inflammatory processing and may be of potential value for preventing atherosclerosis.

Potential for Cell-Transplant Therapy with Human Neuronal Precursors to Treat Neuropathic Pain in Models of PNS and CNS Injury: Comparison of hNT2.17 and hNT2.19 Cell Lines

Effective treatment of sensory neuropathies in peripheral neuropathies and spinal cord injury (SCI) is one of the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord is a logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the potential of transplant of cells to treat chronic pain. Cell lines derived from the human neuronal NT2 cell line parentage, the hNT2.17 and hNT2.19 lines, which synthesize and release the neurotransmitters gamma-aminobutyric acid (GABA) and serotonin (5HT), respectively, have been used to evaluate the potential of cell-based release of antinociceptive agents near the lumbar dorsal (horn) spinal sensory cell centers to relieve neuropathic pain after PNS (partial nerve and diabetes-related injury) and CNS (spinal cord injury) damage in rat models. Both cell lines transplants potently and permanently reverse behavioral hypersensitivity without inducing tumors or other complications after grafting. Functioning as cellular minipumps for antinociception, human neuronal precursors, like these NT2-derived cell lines, would likely provide a useful adjuvant or replacement for current pharmacological treatments for neuropathic pain.

Melittin inhibits atherosclerosis in LPS/high-fat treated mice through atheroprotective actions

AIM

Atherosclerosis is influenced by multiple environmental factors that involve a complex interaction between blood components and the arterial wall and is characterized by inflammatory reactions. Melittin has been used in treatment of various chronic inflammatory diseases. We investigated the effects of melittin regulated atherosclerotic changes in an animal model of atherosclerosis.

METHODS

Atherosclerotic mice were induced by intraperitoneal (i.p) injection of lipopolysaccharide (LPS, 2 mg/kg) three times a week and an atherogenic diet for 12 weeks.

RESULTS

Melittin (0.1 mg/kg) treatment was administered with i.p injection. Melittin treatment showed that total cholesterol and triglyceride levels decreased in atherosclerotic mice however, high-density lipoprotein cholesterol (HDL-C) levels were higher in atherosclerotic mice treated with melittin than in atherosclerotic mice. H&E staining showed that heart and descending aorta were significantly recovered by melittin, compared to atherosclerotic mice. In addition, melittin decreased the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, vascular cell adhesion molecule (VCAM)-1, intercellular adhesion molecule (ICAM)-1, fibronectin and transforming growth factor (TGF)-β1 in atherosclerotic mice. In vitro, melittin decreased LPS-induced THP-1 cells-derived macrophages TNF-α and IL-1β expression levels and nuclear factor (NF)-κB signal pathway.

CONCLUSIONS

These results demonstrate that melittin has an anti-atherogenic effect by suppression of pro-inflammatory cytokines and adhesion molecules.

Effects of Bee Venom Treatment on Growth Performance of Young Pigs

This study examined the effect of whole bee venom (BV) as a potential stimulant of the piglet immune system, on growth performance, blood parameters, plasma protein and immune globulin content of serum. Piglets (n = 97) received combinations of 0.5, 1.0, 1.5, 2.0 and 2.5 mg/kg of parenterally administered BV on 4 occasions between birth and Day 30. In the apipuncture group (n = 31), piglets were acupunctured with the worker honeybee. Two acupoints, GV-1 (Jiao-chao) and GV-20 (Bai-hui), were selected for apipuncture. All piglets (n = 128) in the treatment groups were treated 4 times throughout the study period of 60 days. The control piglets received no treatments. Blood was taken via jugular venipuncture on Day 30 after birth. Body weight and survivability were measured, and changes in hematological values were analyzed. Both the BV injection group and apipuncture group increased body weight and survivability by 26.6% and 21.8%, and 7.9% and 6.7% respectively compared to the controls. The numbers of leukocytes, erythrocytes, lymphocytes and monocytes were not influenced by treatments. However, a potential clinical benefit of high dose therapy was seen in increased populations of leukocytes, lymphocytes and monocytes compared with either the apipuncture or control groups. Other blood parameters such as total protein and albumin were not affected by treatment. However, IgG levels were generally higher in treated groups than in the controls. These findings indicate that BV might be useful to stimulate immuno-competence in pig production, possibly via the primary bioactive components of melittin, phospholipase A 2 and apamin. The administration of BV, either via injection or acupuncture, did not make any differences in growth performance of young pigs. These results would be useful for further purification and characterization of immune boosting agents from BV.

Secondary heat hyperalgesia induced by melittin in humans

Melittin, which is a principal protein of honeybee venom, can induce mechanical hyperalgesia in humans. The characteristics of the melittin induced mechanical hyperalgesia are quantitatively and qualitatively different from those evoked by capsaicin. The aim of the present study was to investigate in detail secondary heat hyperalgesia induced by melittin in humans. In six healthy volunteers, 10 microg of melittin was injected intradermally on the volar forearm, and VAS score to radiant heat stimuli (focused light from a xenon lamp) was assessed around the injection site 5, 30, and 60 min after injection. For normalization purposes, a pain rating index was calculated as the individual heat evoked VAS scores obtained after melittin divided by the individual baseline VAS scores. A two-way ANOVA revealed a significant increase of the pain rating index over time (F=3.6; P=0.03). The pain rating index at 60 min was significantly larger than at 5 min (P=0.04) and at 30 min (P=0.03). These results demonstrated slowly developing secondary heat hyperalgesia after injection of melittin. A possible contribution of peripheral inflammatory responses to the manifestation of secondary heat hyperalgesia is suggested, which in reality render the distinction between the primary and secondary area of heat hyperalgesia unnecessary.

Effects of SKF-96365, a TRPC inhibitor, on melittin-induced inward current and intracellular Ca2+ rise in primary sensory cells

OBJECTIVE

Melittin (MEL) is a major component of bee venom and can produce both persistent spontaneous nociception and pain hypersensitivity when injected subcutaneously in the periphery. The present study aimed to examine the roles of transient receptor potential canonical (TRPC) channels in mediation of MEL-induced activation of primary nociceptive cells.

METHODS

Whole-cell patch-clamp and laser scanning confocal calcium detection were used to evaluate the effects of SKF-96365, a TRPC inhibitor, applied on the acutely isolated dorsal root ganglion (DRG) cells of rat, on MEL-induced increase in intracellular calcium concentration ([Ca(2+)](i)) and inward current.

RESULTS

Under voltage-clamp mode, 43.9% (40/91) DRG cells were evoked to give rise to the inward current by 2 μmol/L MEL, which could be significantly suppressed by 3 doses of SKF-96365 (1, 5 and 10 μmol/L) in a dose-dependent manner. Of the other 210 cells, 67.6% responded to MEL with an intracellular Ca(2+) rise, as revealed by confocal calcium imaging. Of these MEL-sensitive cells, 46.5% (66/142) were suppressed by the highest dose of SKF-96365.

CONCLUSION

MEL-induced activation of small to medium-sized DRG cells can be suppressed by SKF-96365, suggesting the involvement of TRPC channels in the mediation of MEL-induced activation of primary nociceptive cells.

Evaluation of bee venom and hyaluronic acid in the intra-articular treatment of osteoarthritis in an experimental rabbit model

The aim of this study was to investigate bee venom and hyaluronic acid in the intra-articular treatment of osteoarthritis in an experimental rabbit model. Forty-five rabbits were used and they were randomly divided into three groups (BVI, BVII, and HA) and each group was divided to two subgroups to evaluate the radiologic, magnetic resonance imaging, histopathologic, and biochemical evaluation in post treatment second week (a) and twelfth week (b). Radiologically, a significant difference was observed in the HA group (P<0.05). The MRI evaluation of at any time in group BVI(b) was found to be different. No significant differences were seen between the groups, biochemically. Histopathologically, cellularity, and orthochromasia was evident with Safranin-O in the BVI(b) and BVII(a); adhesions were seen in the BVII(a) group and clustering of chondrocyte in the HA(b) group were found to be different. Consequently, intra-articular application of HA and BV for experimental model of osteoarthritis has no significant influence upon recovery after therapy.

Effects of bee venom on glutamate-induced toxicity in neuronal and glial cells

Bee venom (BV), which is extracted from honeybees, is used in traditional Korean medical therapy. Several groups have demonstrated the anti-inflammatory effects of BV in osteoarthritis both in vivo and in vitro. Glutamate is the predominant excitatory neurotransmitter in the central nervous system (CNS). Changes in glutamate release and uptake due to alterations in the activity of glutamate transporters have been reported in many neurodegenerative diseases, including Parkinson's disease, Alzheimer's disease, and amyotrophic lateral sclerosis. To assess if BV can prevent glutamate-mediated neurotoxicity, we examined cell viability and signal transduction in glutamate-treated neuronal and microglial cells in the presence and absence of BV. We induced glutamatergic toxicity in neuronal cells and microglial cells and found that BV protected against cell death. Furthermore, BV significantly inhibited the cellular toxicity of glutamate, and pretreatment with BV altered MAP kinase activation (e.g., JNK, ERK, and p38) following exposure to glutamate. These findings suggest that treatment with BV may be helpful in reducing glutamatergic cell toxicity in neurodegenerative diseases.

Melittin restores proteasome function in an animal model of ALS

Amyotrophic lateral sclerosis (ALS) is a paralyzing disorder characterized by the progressive degeneration and death of motor neurons and occurs both as a sporadic and familial disease. Mutant SOD1 (mtSOD1) in motor neurons induces vulnerability to the disease through protein misfolding, mitochondrial dysfunction, oxidative damage, cytoskeletal abnormalities, defective axonal transport- and growth factor signaling, excitotoxicity, and neuro-inflammation.Melittin is a 26 amino acid protein and is one of the components of bee venom which is used in traditional Chinese medicine to inhibit of cancer cell proliferation and is known to have anti-inflammatory and anti-arthritic effects.The purpose of the present study was to determine if melittin could suppress motor neuron loss and protein misfolding in the hSOD1G93A mouse, which is commonly used as a model for inherited ALS. Meltittin was injected at the 'ZuSanLi' (ST36) acupuncture point in the hSOD1G93A animal model. Melittin-treated animals showed a decrease in the number of microglia and in the expression level of phospho-p38 in the spinal cord and brainstem. Interestingly, melittin treatment in symptomatic ALS animals improved motor function and reduced the level of neuron death in the spinal cord when compared to the control group. Furthermore, we found increased of α-synuclein modifications, such as phosphorylation or nitration, in both the brainstem and spinal cord in hSOD1G93A mice. However, melittin treatment reduced α-synuclein misfolding and restored the proteasomal activity in the brainstem and spinal cord of symptomatic hSOD1G93A transgenic mice.Our research suggests a potential functional link between melittin and the inhibition of neuroinflammation in an ALS animal model.

Melittin activates TRPV1 receptors in primary nociceptive sensory neurons via the phospholipase A2 cascade pathways

Previous studies demonstrated that melittin, the main peptide in bee venom, could cause persistent spontaneous pain, primary heat and mechanical hyperalgesia, and enhance the excitability of spinal nociceptive neurons. However, the underlying mechanism of melittin-induced cutaneous hypersensitivity is unknown. Effects of melittin applied topically to acutely dissociated rat dorsal root ganglion neurons were studied using whole-cell patch clamp and calcium imaging techniques. Melittin induced intracellular calcium increases in 60% of small (<25 μm) and medium (<40 μm) diameter sensory neurons. In current clamp, topical application of melittin evoked long-lasting firing in 55% of small and medium-sized neurons tested. In voltage clamp, melittin evoked inward currents in sensory neurons in a concentration-dependent manner. Repeated application of melittin caused increased amplitude of the inward currents. Most melittin-sensitive neurons were capsaicin-sensitive, and 65% were isolectin B4 positive. Capsazepine, the TRPV1 receptor inhibitor, completely abolished the melittin-induced inward currents and intracellular calcium transients. Inhibitions of signaling pathways showed that phospholipase A(2), but not phospholipase C, was involved in producing the melittin-induced inward currents. Inhibitors of cyclooxygenases (COX) and lipoxygenases (LOX), two key components of the arachidonic acid metabolism pathway, each partially suppressed the inward current evoked by melittin. Inhibitors of protein kinase A (PKA), but not of PKC, also abolished the melittin-induced inward currents. These results indicate that melittin can directly excite small and medium-sized sensory neurons at least in part by activating TRPV1 receptors via PLA2-COXs/LOXs cascade pathways.

Effect of bee venom acupuncture on methamphetamine-induced hyperactivity, hyperthermia and Fos expression in mice

Acupuncture has been used to treat drug addiction by nicotine, alcohol, cocaine and morphine. This study was designed to investigate the effect of bee venom (BV) acupuncture on hyperactivity and hyperthermia induced by acute exposure to methamphetamine (METH, 1mg/kg, s.c.) in mice. Diluted BV (20μl of 0.01, 0.1, 1 and 10mg/ml in saline, s.c.) was administered bilaterally into the Zusanli acupoint (ST36) or control points (SP9 or GB39 or tail base). BV injection into ST36 dose dependently reduced METH-induced hyperactivity and hyperthermia, while BV injection (1mg/ml) into control points did not produce these suppressive effects. METH injection significantly increased Fos expression in several brain regions including nucleus accumbens (NA), caudate putamen (CPU), ventral tegmental area (VTA), substantia nigra (SN) and locus coeruleus (LC). Interestingly, BV (1mg/ml) injection into ST36 further increased METH-induced Fos expression in NA (core and shell), SN and LC. When we performed sciatic denervation or combination treatment of BV and lidocaine (BV diluted in 5% lidocaine solution), the enhancement of Fos elevation by BV was completely blocked in the NA, SN and LC in METH-injected mice, indicating that BV-induced peripheral nerve stimulation played an important role in the BV effect. Furthermore, the effects of BV were completely blocked by the α₂-adrenoceptor antagonist, idazoxan (3mg/kg, i.p.), but not by β-adrenoceptor antagonist, propranolol (10mg/kg, i.p.). Taken together, these findings suggest that BV acupuncture into ST36 may modulate METH-induced hyperactivity, hyperthermia and Fos expression through activation of the peripheral nerve and the central α₂-adrenergic activation.

The nociceptive and anti-nociceptive effects of bee venom injection and therapy: a double-edged sword

Bee venom injection as a therapy, like many other complementary and alternative medicine approaches, has been used for thousands of years to attempt to alleviate a range of diseases including arthritis. More recently, additional theraupeutic goals have been added to the list of diseases making this a critical time to evaluate the evidence for the beneficial and adverse effects of bee venom injection. Although reports of pain reduction (analgesic and antinociceptive) and anti-inflammatory effects of bee venom injection are accumulating in the literature, it is common knowledge that bee venom stings are painful and produce inflammation. In addition, a significant number of studies have been performed in the past decade highlighting that injection of bee venom and components of bee venom produce significant signs of pain or nociception, inflammation and many effects at multiple levels of immediate, acute and prolonged pain processes. This report reviews the extensive new data regarding the deleterious effects of bee venom injection in people and animals, our current understanding of the responsible underlying mechanisms and critical venom components, and provides a critical evaluation of reports of the beneficial effects of bee venom injection in people and animals and the proposed underlying mechanisms. Although further studies are required to make firm conclusions, therapeutic bee venom injection may be beneficial for some patients, but may also be harmful. This report highlights key patterns of results, critical shortcomings, and essential areas requiring further study.

Bee venom inhibits tumor angiogenesis and metastasis by inhibiting tyrosine phosphorylation of VEGFR-2 in LLC-tumor-bearing mice

Bee venom (BV) treatment is the therapeutic application of honeybee venom (HBV) for treating various diseases in Oriental medicine. In the present work, the authors investigated the functional specificity of BV as an angiogenesis inhibitor using in vitro models and in vivo mouse angiogenesis and lung metastasis models. BV significantly inhibited the viability of Lewis lung carcinoma (LLC) cells but did not affect peripheral blood mononuclear lymphocytes (PBML) cells. BV also inhibited vascular endothelial growth factor (VEGF)-induced proliferation, migration and capillary-like tube formation of human umbilical vein endothelial cells (HUVECs). Western blotting analysis showed that BV inhibited AKT and MAPK phosphorylation in LLC cells and HUVECs and down regulated expression of VEGF and VEGFR-2 of LLC cells and HUVECs. Also, BV effectively disrupted VEGF-induced neovascularization in Matrigel plugs in our in vivo angiogenesis assay. When given subcutaneously, BV also significantly suppressed tumor angiogenesis through inhibition of VEGF and VEGFR-2 in LLC model. Mice bearing subcutaneous LLC tumors were treated with 1mug/ml or 10mug/ml of BV. They showed reductions ranging between 49% and 62% in primary tumor volume and reduction of spontaneous pulmonary metastasis occurrences. Furthermore, BV treatment in the spontaneous lung metastases model after primary tumor excision prolonged their median survival time from 27 to 58days. These results suggest that the tumor-specific anti-angiogenic activity of BV takes effect during different stages of tumor progression by blocking the tyrosine phosphorylation of VEGFR-2, and validate the application of BV in lung cancer treatment.

Bee venom protects hepatocytes from tumor necrosis factor-alpha and actinomycin D

Honeybee (Apis mellifera) venom (BV) has a broad array of therapeutic applications in traditional medicine to treat variety of diseases. It is also known that BV possesses anti-inflammatory and anticancer effect and that it can inhibit proliferation and induces apoptosis in cancer cells, but there is no evidence of information regarding anti-apoptosis of BV on hepatocytes. In the present study, we investigated the anti-apoptotic effect of BV on tumor necrosis factor (TNF)-alpha with actinomycin (Act) D induces apoptosis in hepatocytes. TNF-alpha/Act D-treated hepatocytes were exposed to different low concentration (1, 10 and 100 ng/mL) of BV. Our results showed statistically significant inhibition in DNA damage caused by BV treatment compared to corresponding TNF-alpha/Act D-treated hepatocytes. BV suppressed TNF-alpha/Act Dtreated activation of bcl-2 family and caspase family, which resulted in inhibition of cytochrome c release and PARP cleavage. These results demonstrate that low concentration BV possess a potent suppressive effect on anti-apoptotic responses of TNF-alpha/Act D-treated hepatocytes and suggest that these compounds may contribute substantial therapeutic potential for the treatment of liver diseases.

Microinjection of morphine into thalamic nucleus submedius depresses bee venom-induced inflammatory pain in the rat

Previous studies have provided evidence of the existence of a pain modulatory feedback pathway consisting of thalamic nucleus submedius (Sm)–ventrolateral orbital cortex-periaqueductal grey pathway, which is activated during acute pain and leads to depression of transmission of nociceptive information in the spinal dorsal horn. The aim of this study was to test the hypothesis that morphine microinjection into the Sm decreased spontaneous pain and bilateral thermal hyperalgesia, as well as ipsilateral mechanical allodynia, induced by subcutaneous injections of bee venom into the rat hind paw. Morphine (1.0, 2.5 or 5.0 &#x006d;̀g in 0.5 μL) injected into the Sm, contralateral to the bee venominjected paw, depressed spontaneous nociceptive behaviour in a dose-dependent manner. Furthermore, morphine significantly decreased bilateral thermal hyperalgesia and ipsilateral mechanical allodynia 2 h after bee venom injection. These morphine-induced effects were antagonized by 1.0 μg naloxone (an opioid antagonist) microinjected into the Sm 5 min before morphine administration. The results provided further support for the important role of the Sm and Sm-opioid receptors in inhibiting nociceptive behaviour and indicated for the first time that Sm opioid receptors were also effective in inhibiting the hypersensitivity provoked by bee venom-induced inflammation.

Roles of the hippocampal formation in pain information processing

Pain is a complex experience consisting of sensory-discriminative, affective-motivational, and cognitive-evaluative dimensions. Now it has been gradually known that noxious information is processed by a widely-distributed, hierarchically- interconnected neural network, referred to as neuromatrix, in the brain. Thus, identifying the multiple neural networks subserving these functional aspects and harnessing this knowledge to manipulate the pain response in new and beneficial ways are challenging tasks. Albeit with elaborate research efforts on the cortical responses to painful stimuli or clinical pain, involvement of the hippocampal formation (HF) in pain is still a matter of controversy. Here, we integrate previous animal and human studies from the viewpoint of HF and pain, sequentially representing anatomical, behavioral, electrophysiological, molecular/biochemical and functional imaging evidence supporting the role of HF in pain processing. At last, we further expound on the relationship between pain and memory and present some unresolved issues.

Nociception-induced spatial and temporal plasticity of synaptic connection and function in the hippocampal formation of rats: a multi-electrode array recording

Background

Pain is known to be processed by a complex neural network (neuromatrix) in the brain. It is hypothesized that under pathological state, persistent or chronic pain can affect various higher brain functions through ascending pathways, leading to co-morbidities or mental disability of pain. However, so far the influences of pathological pain on the higher brain functions are less clear and this may hinder the advances in pain therapy. In the current study, we studied spatiotemporal plasticity of synaptic connection and function in the hippocampal formation (HF) in response to persistent nociception.

Results

On the hippocampal slices of rats which had suffered from persistent nociception for 2 h by receiving subcutaneous bee venom (BV) or formalin injection into one hand paw, multisite recordings were performed by an 8 × 8 multi-electrode array probe. The waveform of the field excitatory postsynaptic potential (fEPSP), induced by perforant path electrical stimulation and pharmacologically identified as being activity-dependent and mediated by ionotropic glutamate receptors, was consistently positive-going in the dentate gyrus (DG), while that in the CA1 was negative-going in shape in naïve and saline control groups. For the spatial characteristics of synaptic plasticity, BV- or formalin-induced persistent pain significantly increased the number of detectable fEPSP in both DG and CA1 area, implicating enlargement of the synaptic connection size by the injury or acute inflammation. Moreover, the input-output function of synaptic efficacy was shown to be distinctly enhanced by the injury with the stimulus-response curve being moved leftward compared to the control. For the temporal plasticity, long-term potentiation produced by theta burst stimulation (TBS) conditioning was also remarkably enhanced by pain. Moreover, it is strikingly noted that the shape of fEPSP waveform was drastically deformed or split by a TBS conditioning under the condition of persistent nociception, while that in naïve or saline control state was not affected. All these changes in synaptic connection and function, confirmed by the 2-dimentional current source density imaging, were found to be highly correlated with peripheral persistent nociception since pre-blockade of nociceptive impulses could eliminate all of them. Finally, the initial pharmacological investigation showed that AMPA/KA glutamate receptors might play more important roles in mediation of pain-associated spatiotemporal plasticity than NMDA receptors.

Conclusion

Peripheral persistent nociception produces great impact upon the higher brain structures that lead to not only temporal plasticity, but also spatial plasticity of synaptic connection and function in the HF. The spatial plasticity of synaptic activities is more complex than the temporal plasticity, comprising of enlargement of synaptic connection size at network level, deformed fEPSP at local circuit level and, increased synaptic efficacy at cellular level. In addition, the multi-synaptic model established in the present investigation may open a new avenue for future studies of pain-related brain dysfunctions at the higher level of the neuromatrix.

Models and mechanisms of hyperalgesia and allodynia

Hyperalgesia and allodynia are frequent symptoms of disease and may be useful adaptations to protect vulnerable tissues. Both may, however, also emerge as diseases in their own right. Considerable progress has been made in developing clinically relevant animal models for identifying the most significant underlying mechanisms. This review deals with experimental models that are currently used to measure (sect. II) or to induce (sect. III) hyperalgesia and allodynia in animals. Induction and expression of hyperalgesia and allodynia are context sensitive. This is discussed in section IV. Neuronal and nonneuronal cell populations have been identified that are indispensable for the induction and/or the expression of hyperalgesia and allodynia as summarized in section V. This review focuses on highly topical spinal mechanisms of hyperalgesia and allodynia including intrinsic and synaptic plasticity, the modulation of inhibitory control (sect. VI), and neuroimmune interactions (sect. VII). The scientific use of language improves also in the field of pain research. Refined definitions of some technical terms including the new definitions of hyperalgesia and allodynia by the International Association for the Study of Pain are illustrated and annotated in section I.

Radioprotective Effects of Honeybee Venom (Apis mellifera) Against 915-MHz Microwave Radiation–Induced DNA Damage in Wistar Rat Lymphocytes: In Vitro Study

The aim of this study is to investigate the radioprotective effect of bee venom against DNA damage induced by 915-MHz microwave radiation (specific absorption rate of 0.6 W/kg) in Wistar rats. Whole blood lymphocytes of Wistar rats are treated with 1 μg/mL bee venom 4 hours prior to and immediately before irradiation. Standard and formamidopyrimidine-DNA glycosylase (Fpg)–modified comet assays are used to assess basal and oxidative DNA damage produced by reactive oxygen species. Bee venom shows a decrease in DNA damage compared with irradiated samples. Parameters of Fpg-modified comet assay are statistically different from controls, making this assay more sensitive and suggesting that oxidative stress is a possible mechanism of DNA damage induction. Bee venom is demonstrated to have a radioprotective effect against basal and oxidative DNA damage. Furthermore, bee venom is not genotoxic and does not produce oxidative damage in the low concentrations used in this study.

Imbalance between excitatory and inhibitory amino acids at spinal level is associated with maintenance of persistent pain-related behaviors

Although the postsynaptic events responsible for development of pathological pain have been intensively studied, the relative contribution of presynaptic neurotransmitters to the whole process remains less elucidated. In the present investigation, we sought to measure temporal changes in spinal release of both excitatory amino acids (EAAs, glutamate and aspartate) and inhibitory amino acids (IAAs, glycine, ?-aminobutyric acid and taurine) in response to peripheral inflammatory pain state. The results showed that following peripheral chemical insult induced by subcutaneous bee venom (BV) injection, there was an initial, parallel increase in spinal release of both EAAs and IAAs, however, the balance between them was gradually disrupted when pain persisted longer, with EAAs remaining at higher level but IAAs at a level below the baseline. Moreover, the EAAs-IAAs imbalance at the spinal level was dependent upon the ongoing activity from the peripheral injury site. Intrathecal blockade of ionotropic (NMDA and non-NMDA) and metabotropic (mGluRI, II, III) glutamate receptors, respectively, resulted in a differential inhibition of BV-induced different types of pain (persistent nociception vs. hyperalgesia, or thermal vs. mechanical hyperalgesia), implicating that spinal antagonism of any specific glutamate receptor subtype fails to block all types of pain-related behaviors. This result provides a new line of evidence emphasizing an importance of restoration of EAAs-IAAs balance at the spinal level to prevent persistence or chronicity of pain.

Microarray analysis of gene expression profiles in response to treatment with bee venom in lipopolysaccharide activated RAW 264.7 cells

AIM OF THE STUDY

The therapeutic application of bee venom (BV) has been used in traditional medicine to treat diseases such as arthritis, rheumatism and pain. Macrophages produce molecules that are known to play roles in inflammatory responses.

MATERIAL AND METHODS

We performed microarray analysis to evaluate the global gene expression profiles of RAW264.7 macrophage cells treated with BV. In addition, six genes were subjected to real-time PCR to confirm the results of the microarray. The cells were treated with lipopolysaccharide (LPS) or BV plus LPS for 30 min or 1h.

RESULTS

124 genes were found to be up-regulated and 158 were found to be down-regulated in cells that were treated with BV plus LPS for 30 min, whereas 211 genes were up-regulated and 129 were down-regulated in cells that were treated with BV plus LPS for 1h when compared with cells that were treated with LPS alone. Furthermore, the results of real-time PCR were similar to those of the microarray. BV inhibited the expression of specific inflammatory genes that were up-regulated by nuclear factor-kappa B in the presence of LPS, including mitogen-activated protein kinase kinase kinase 8 (MAP3K8), TNF, TNF-alpha-induced protein 3 (TNFAIP3), suppressor of cytokine signaling 3 (SOCS3), TNF receptor-associated factor 1 (TRAF1), JUN, and CREB binding protein (CBP).

CONCLUSIONS

These results demonstrate the potent activity of BV as a modulator of the LPS-mediated nuclear factor-kappaB (NF-kappaB)/MAPK pathway in activated macrophages. In addition, these results can be used to understand other effects of BV treatment.

Suppressive effects of bee venom on the immune responses in collagen-induced arthritis in rats

The effect of bee venom (BVA) on the development of type II collagen (CII)-induced arthritis (CIA) in rats has been studied. Male rats were immunized with an emulsion of 200 microg of CII and complete Freund's adjuvant (CFA). The rats were then given intraperitoneally (i.p.) injection of a suspension of BVA or saline during the experiment. The effect of BVA on cellular responses to CII was examined. In the control rats, the onset of arthritis was observed at the 24th day after the CII-immunization, and the severity of CIA was developed gradually. As compared with rats treated with saline, BVA i.p. injected at doses of more than 20 microl/100g mouse once a day for 14 days inhibited the ability of inguinal lymph node cells to produce T cell cytokines interleukin-1beta, -2, -6, tumor necrosis factor-alpha and interferon-gamma when the cells were obtained from rats 24 days after immunization and cultured in vitro with CII. When rats were injected i.p. with sheep red blood cells, hemagglutination titers in BVA-treated and control rats did not differ significantly when low doses of BVA was given to rats. However, i.p. injection of BVA at doses of more than 10 microl/100g/day suppressed antibody production. Pretreatment of rats with BVA could inhibit the development of collagen arthritis even when 10-20 microl/100g/day of the BVA were used for pretreatment. Interestingly, higher doses than 10 microlBVA/100g mouse were much effective for arthritis incidence. Treatment of rats with BVA prevented the development of collagen arthritis in a dose-dependent manner. Doses of BVA (15 and 20 microl/100g) resulted in decreased incidence of arthritis. In conclusion, therapeutic i.p injection with BVA improved the clinical course of the disease and the immune response to CII.

Bee Venom, Immunostimulant or Immunosuppressor? Insight into the Effect on Matrix Metalloproteinases and Interferons

The current evidence has defined conflicting properties for bee venom. The goal of this study was to determine whether bee venom (BV) is an immunosuppressor or immunostimulant. The WEHI-164, HT-1080, and K562 cell lines were used for assaying toxicity, proliferative response, matrix metalloproteinase-2 and -9 (MMP-2 and MMP-9) activity, and interferon production. The Australian and Iranian BV (ABV and IBV) were used at concentrations of 0.025-1 microg/ml in triplicate and 2-fold dilutions. MMP-2 and -9 activities were evaluated using the zymography method. The production of interferons (IFN-alpha and IFN-beta) were assessed using enzyme-linked immunoassay procedure. Our results show no significant difference between two sources of honeybee venom (ABV and IBV) when they are added to an identified cell line, whereas the response of various cell lines against BV could be different. The increasing amounts of ABV and/or IBV (between doses 0.025-0.5 microg/ml) to human monocyte cell line (K562) exhibit a significant increase in proliferative response. Our data show that the immunomodulatory effect of ABV and/or IBV on MMP-2 and MMP-9 activity in both cell culture media, WEHI-164 and K562, is similar. The stimulatory effect of BV on MMP-2 and -9 activities is occurred between doses 0-0.05 microg/ ml. In contrast, the inhibitory effect of BV on these two MMPs is seen at concentrations of >0.05 microg/ml. The ABV and/or IBV has no influence on IFN-alpha production in cell culture media, whereas adding the BV to K562 cell line could significantly increase the production level of IFN-beta only on day 8 posttreatment. We conclude that time- and dose-dependent response as well as the type of treated cell line could determine the immunosuppressive and/or immunostimulant property of bee venom that could be effective in future therapeutic strategies.

Spinal Metabotropic Glutamate Receptors (mGluRs) are Involved in the Melittin-induced Nociception in Rats

Intraplantar injection of melittin has been known to induce sustained decrease of mechanical threshold and increase of spontaneous flinchings. The present study was undertaken to investigate how the melittin-induced nociceptive responses were modulated by changes of metabotropic glutamate receptor (mGluR) activity. Changes in paw withdrawal threshold (PWT), number of flinchings and paw thickness were measured at a given time point after injection of melittin (10 microg/paw) into the mid-plantar area of rat hindpaw. To observe the effects of mGluRs on the melittin-induced nociceptions, group I mGluR (AIDA, 100 microg and 200 microg), mGluR(1) (LY367385, 50 microg and 100 microg) and mGluR(5) (MPEP, 200 microg and 300 microg) antagonists, group II (APDC, 100 microg and 200 microg) and III (L-SOP, 100 microg and 200 microg) agonists were intrathecally administered 20 min before melittin injection. Intraplantar injection of melittin induced a sustained decrease of mechanical threshold, spontaneous flinchings and edema. The effects of melittin to reduce mechanical threshold and to induce spontaneous flinchings were significantly suppressed following intrathecal pre-administration of group I mGluR, mGluR(1) and mGluR(5) antagonists, group II and III mGluR agonists. Group I mGluR antagonists and group II and III mGluR agonists had no significant effect on melittin-induced edema. These experimental findings indicate that multiple spinal mGluRs are involved in the modulation of melittin-induced nociceptive responses.