Cell adhesion molecules involved in the leukocyte recruitment induced by venom of the snake Bothrops jararaca

It has been shown that Bothrops jararaca venom (BjV) induces a significant leukocyte accumulation, mainly neutrophils, at the local of tissue damage. Therefore, the role of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1), LECAM-1, CD18, leukocyte function-associated antigen-1 (LFA-1) and platelet endothelial cell adhesion molecule-1 (PECAM-1) on the BjV-induced neutrophil accumulation and the correlation with release of LTB4, TXA2, tumor necrosis factor-alpha, interleukin (IL)-1 and IL-6 have been investigated. Anti-mouse LECAM-1, LFA-1, ICAM-1 and PECAM-1 monoclonal antibody injection resulted in a reduction of 42%, 80%, 66% and 67%, respectively, of neutrophil accumulation induced by BjV (250 microg/kg, intraperitoneal) injection in male mice compared with isotype-matched control injected animals. The anti-mouse CD18 monoclonal antibody had no significant effect on venom-induced neutrophil accumulation. Concentrations of LTB(4), TXA(2), IL-6 and TNF-alpha were significant increased in the peritoneal exudates of animals injected with venom, whereas no increment in IL-1 was detected. This results suggest that ICAM-1, LECAM-1, LFA-1 and PECAM-1, but not CD18, adhesion molecules are involved in the recruitment of neutrophils into the inflammatory site induced by BjV. This is the first in vivo evidence that snake venom is able to up-regulate the expression of adhesion molecules by both leukocytes and endothelial cells. This venom effect may be indirect, probably through the release of the inflammatory mediators evidenced in the present study.     

Angiostatin-like molecules are generated by snake venom metalloproteinases

Angiostatin is a plasminogen-derived anti-angiogenic factor composed of its first four kringle structures. This molecule is generated by proteolytic cleavage of plasminogen by some proteolytic enzymes in vitro. Since venoms of viper snakes are a rich source of both serine- and metalloproteinase, we hypothesized that angiostatin-like polypeptides could be generated during the envenomation after snake bites and play a pathophysiological role in the local tissue damage and regeneration. Our results showed that crude venoms from several species of Bothrops snakes were able to generate angiostatin-like polypeptides and purified metalloproteinases but not serine proteinases from Bothrops jararaca and Bothrops moojeni venoms were responsible for their generation in vitro. The putative plasminogen cleavage sites by the crude venoms and purified proteinases were determined by N-terminal amino acid sequencing of the angiostatin-like molecules. Angiostatin-like peptides derived from human plasminogen digestion by jararhagin, a metalloproteinase isolated from B. jararaca venom, inhibited endothelial cell proliferation in vitro. These results indicate that angiostatin-like molecules can be generated upon snakebite envenomations and may account for the poor and incomplete regenerative response observed in the damaged tissue.     

Modification of the toxicity of Bothrops atrox poison by interventions in the coagulation and kallikrein system of prey

LD50-determinations with venom mixtures from different age groups of Bothrops atrox were carried out on differently pretreated mice. No differences were seen in the LD50 when comparing untreated mice with mice previously defibrinogenated with batroxobin. Inhibition of the coagulation-, kallikrein-kinin- and fibrinolytic system by pretreatment with batroxobin and aprotinin led to a significantly decreased toxicity of the venom mixtures of all age groups. The age-related difference in toxicity had practically disappeared. Furthermore, the number of mice of the latter group dying within one hour after the venom injection was strongly reduced as compared to untreated and only batroxobin-treated animals. Tests performed on rats showed that the rapidly occurring lethality following the venom injection as a consequence of circulatory disturbances (strong fall of arterial blood pressure, bradycardia, dyspnea), may be prevented almost completely by preincubation of the venom with aprotinin.     

Effects of Jarastatin, a Novel Snake Venom Disintegrin, on Neutrophil Migration and Actin Cytoskeleton Dynamics

A new disintegrin, an RGD-containing peptide of 6 kDa called jarastatin, was purified from Bothrops jararaca venom. It is a potent inhibitor of platelet aggregation induced by ADP, collagen, and thrombin. The effect of jarastatin on neutrophil migration in vivo and in vitro and on the actin cytoskeleton dynamics of these cells was investigated. Incubation in vitro with jarastatin significantly inhibited, in a concentration-dependent manner, the chemotaxis of human neutrophils toward fMLP, IL-8, and jarastatin itself. Despite this inhibitory effect, jarastatin induced neutrophil chemotaxis. A significant increase of F-actin content was observed in jarastatin-treated neutrophils. Furthermore, as demonstrated by confocal microscopy after FITC-phalloidin labeling, these cells accumulated F-actin at the plasmalemma, a distribution similar to that observed in fMLP-stimulated cells. Pretreatment of mice with jarastatin inhibited neutrophil migration into peritoneal cavities induced by carrageenan injection. The results suggest that binding of jarastatin to neutrophil integrins promotes cellular activation and triggers a dynamic alteration of the actin filament system and that this is one of the first event in integrin-mediated signaling.     

The venom of South American rattlesnakes inhibits macrophage functions and is endowed with anti-inflammatory properties

The injection of Crotalus durissus terrificus venom into the foot pad of mice did not induce a significant inflammatory response as evaluated by oedema formation, increased vascular permeability and cell migration. The subcutaneous injection of the venom, or its addition to cell cultures, had an inhibitory effect on the spreading and phagocytosis of resident macrophages, without affecting the viability of the cells. This effect was not observed when the venom was added to cultures of thioglycollate elicited macrophages, but it was able to inhibit these macrophage functions when the cells were obtained from animals injected simultaneously with the venom and thioglycollate. These observations suggest that the venom interferes with the mechanisms of macrophage activation. Leukocyte migration induced by intraperitoneal injection of thioglycollate was also inhibited by previous venom injection. This down-regulatory activity of the venom on macrophage functions could account for the mild inflammatory response observed in the site of the snake bite in Crotalus durissus terrificus envenomation in man.     

Characterization of beta-adrenoceptors responsible for venom production in the venom gland of the snake Bothrops jararaca

We have shown that the stimulation of beta-adrenoceptors is an important step in venom production in the Bothrops jararaca venom gland. In the present study, the pharmacological profile of the beta-adrenoceptor present in Bothrops jararaca venom gland was characterized by radioligand binding assay and by the ability of isoprenaline to promote accumulation of cyclic AMP in dispersed secretory cells. In both cases, the venom glands were obtained from non-extracted snakes (quiescent stage) or from snakes which venom was extracted 4 days before sacrifice (venom production stimulated stage). [125I]-iodocyanopindolol ([125I]-ICYP) bound to extracted gland membranes in a concentration-dependent and saturable manner, but with low affinity. Propranolol, beta1- or beta2-selective adrenoceptors ligands displaced the [125I]-ICYP binding with low affinity, while selective beta3-adrenoceptor ligands did not displace the [125I]-ICYP binding. The displacement of [125I]-ICYP by propranolol was similar in non-extracted and extracted glands, showing the presence of beta-adrenoceptors in both stages. In dispersed secretory cells of non-extracted glands, isoprenaline (1 microM) increased the cyclic AMP production and propranolol (10 microM) was able to block this effect. On the other hand, in extracted glands, isoprenaline had no effect. The results suggest that the beta-adrenoceptors present in the Bothrops jararaca venom glands are different from those (beta1, beta2 or beta3) described in mammals, but are coupled to the Gs protein, like the known beta-adrenoceptor subtypes. Moreover, previous in vivo stimulation of venom production desensitizes the beta-adrenoceptors system and, although the receptors could be detected by binding studies, they are not coupled to the Gs protein, indicating that beta-adrenoceptors stimulation contributes to the initial steps of venom synthesis.     

Effect of heparin and antivenom on skeletal muscle damage produced by Bothrops jararacussu venom

We examined the effect of treatment with heparin and polyvalent antivenom on mice muscle Extensor digitorum longus (EDL) regeneration, after damage induced by injection of Bothrops jararacussu crude venom over the muscle of the right posterior limb. The mice were separated into groups and each group received treatment, by intravenous route with either high molecular weight heparin (H), low molecular weight heparin (LMWH), polyvalent antivenom (PAV) or with the combination of PAV plus H or PAV plus LMWH at 15 minutes and 4 hours after the injection of the venom. Myotoxicity was measured by the increase in plasma creatine kinase (CK) activity at two hours after the injection of the venom. The histological changes in EDL at 1, 3, 7 and 21 days after the injection of the venom were analyzed by light microscopy. In each group the normal and regenerated muscle fibers were quantified using Scion Image computer program. We also evaluated in vitro, the influence of these substances in the proteolytic and phospholipase activities of the venom. Heparins decreased the proteolytic activity of the venom but did not affect its phospholipase activity. However the PAV antagonized both activities. PAV and its combinations showed antimyotoxic activity, according to the magnitude of CK plasma levels. At 21 days the regeneration was observed in all animals, also in those that received only the venom. All treatments, except LMWH, promote a significant increase in the number of muscle fibers.     

Programmed cell death in Trypanosoma cruzi induced by Bothrops jararaca venom

Cells die through a programmed process or accidental death, know as apoptosis or necrosis, respectively. Bothrops jararaca is a snake whose venom inhibits the growth of Trypanosoma cruzi epimastigote forms causing mitochondrion swelling and cell death. The aim of the present work was to determine the type of death induced in epimastigotes of T. cruzi by this venom. Parasite growth was inhibited after venom treatment, and 50% growth inhibition was obtained with 10 microg/ml. Ultrastructural observations confirmed mitochondrion swelling and kinetoplast disorganization. Furthermore, cytoplasmic condensation, loss of mitochondrion membrane potential, time-dependent increase in phosphatidylserine exposure at the outer leaflet plasma membrane followed by permeabilization, activation of caspase like protein and DNA fragmentation were observed in epimastigotes throughout a 24 h period of venom treatment. Taken together, these results indicate that the stress induced in epimastigote by this venom, triggers a programmed cell death process, similar to metazoan apoptosis, which leads to parasite death.     

Plant natural products active against snake bite--the molecular approach

The article surveys the substances identified in plants reputed to neutralize the effects of snake venoms. Protective activity of many of them against the lethal action of the venom of the jararaca (Bothrops jararaca) snake was confirmed by biological assays. It was shown that all belong to chemical classes capable of interacting with macromolecular targets--receptors and enzymes. In a few cases it has been shown that exogenous natural micromolecules can mimic the biological activity of endogenous macromolecules. From the evidence presented, it can be inferred that micromolecules which neutralize the action of snake venoms mechanistically replace endogenous antitoxic serum proteins with venom neutralizing capacity such as produced by some animals.     

Histopathological changes in avian kidney caused by Bothrops insularis (jararaca ilh a) venom and a phospholipase A2-containing fraction

The histopathological changes induced in avian kidney by the intramuscular injection of Bothrops insularis (jararaca ilh a) venom and its phospholipase A2 (PLA2)-containing fraction were examined. Acute experiments (3 h and 24 h) with B. insularis crude venom (20 microg and 80 microg) or its PLA2-contaning fraction (10 microg and 40 microg) resulted in significant structural damage to the kidneys of 5-12-day-old chicks. Histopathological analysis indicated that the venom and its fraction acted on the renal tubules and glomeruli. The morphological changes, although widespread, varied in intensity from cell to cell, and from tubule to tubule in venom-injected chicks. The tubular and glomerular changes produced by the venom and its PLA2-containing fraction may be the result of a direct cytotoxic effect potentiated by ischemia-related disturbances in the regional hemodynamics. The venom and its fraction affected more segments along reptilian-type nephrons than along mammalian ones. This divergent sensitivity to the venom and its fraction may reflect the species-specific characteristics of B. insularis snake, an example of geographical isolation influencing its diet which is almost exclusively avian.     

Bothrops jararaca venom proteome rearrangement upon neonate to adult transition

The pharmacological activities displayed by Bothrops jararaca venom undergo a significant ontogenetic shift. Similarly, the diet of this species changes from ectothermic prey in early life to endothermic prey in adulthood. In this study we used large and representative newborn and adult venom samples consisting of pools from 694 and 110 specimens, respectively, and demonstrate a significant ontogenetic shift in the venom proteome complexity of B. jararaca. 2-DE coupled to MS protein identification showed a clear rearrangement of the toxin arsenal both in terms of the total proteome, as of the glycoproteome. N-glycosylation seems to play a key role in venom protein variability between newborn and adult specimens. Upon the snake development, the subproteome of metalloproteinases undergoes a shift from a P-III-rich to a P-I-rich profile while the serine proteinase profile does not vary significantly. We also used isobaric tag labeling (iTRAQ) of venom tryptic peptides for the first time to examine the quantitative changes in the venom toxins of B. jararaca upon neonate to adult transition. The iTRAQ analysis showed changes in various toxin classes, especially the proteinases. Our study expands the in-depth understanding of venom complexity variation particularly with regard to toxin families that have been associated with envenomation pathogenesis.     

Subpopulations of mononuclear leukocytes associated with inhibition of Ehrlich ascites tumor growth by treatment with Bothrops jararaca venom

Snake venoms have been used as antineoplastic substances in several experimental models. We demonstrated in previous studies that Bothrops jararaca venom (BjV) induces inhibition of Ehrlich ascites tumor (EAT) growth accompanied by an increase of mononuclear (MN) leukocytes in all groups inoculated with EAT and/or venom. The objective of the present study was to characterize the subpopulations of MN leukocytes involved in the inhibition of EAT growth by treatment with BjV. Swiss mice were inoculated with 1.0x10(3) EAT cells by the intraperitoneal route and treated with 0.4 mg/kg of BjV by the same route (Group TV). Treatment was started 24 h after tumor cell inoculation and consisted of five intraperitoneal injections performed at 72 h intervals. After 2, 8 and 14 days, groups of animals were sacrificed and the number of B, TCD4 and TCD8 lymphocytes, macrophages and natural killer cells present in the peritoneal cavity was determined by flow cytometry. The control group consisted of animals inoculated with EAT and treated with 0.1 ml of saline under the same conditions as the experimental group (Group T). Two additional control groups consisted of animals not inoculated with EAT and treated with saline or venom. Data were analyzed statistically by the Kruskal-Wallis non-parametric test for independent samples. On the 2nd and 8th day we observed a difference between groups T and TV (group T > group TV) for all cell types, except natural killer cells, that only differed on the 2nd day. However, on the 14th day there was no difference in MN cells among groups. These data suggest that the inhibition of EAT is related to the toxic action of BjV on tumor cells and/or to the proteolytic effect of the venom on the mediators produced by the cells for growth modulation.     

Comparative effect of Phoneutria nigriventer spider venom and capsaicin on the rat paw oedema

Capsaicin, the pungent component of hot peppers, and the venom of the spider Phoneutria nigriventer are able to activate sensory nerves resulting in cutaneous neurogenic plasma extravasation. This study was undertaken to compare the ability of these substances to evoke oedema in the rat hind-paw and mechanisms underlying this effect. Subplantar injection of either Phoneutria nigriventer venom (PNV; 1-100 microg/paw) or capsaicin (10-200 microg/paw) caused a significant paw oedema that was potentiated by CGRP (10 pmol/paw). In rats treated neonatally with capsaicin to deplete neuropeptides, the paw oedema induced by either PNV (100 microg/paw) or capsaicin (100 microg/paw) was partially reduced (P<0.05). The tachykinin NK1 receptor antagonist SR140333 (0.2 micromol/kg; i.v.) prevented the paw oedema induced by the tachykinin NK1 receptor agonist GR73632 (30 pmol/paw) and partially reduced paw oedema induced by PNV or capsaicin. Treatment of rats with compound 48/80 (5 mg/kg; s.c. 3 days) or with both H1 receptor antagonist (mepyramine; 1 nmol/paw) and 5-HT receptor antagonist (methysergide; 1 nmol/paw) significantly inhibited PNV- or capsaicin-induced paw oedema. The combined treatment with mepyramine and methysergide and SR140333 further reduced PNV- and capsaicin-induced paw oedema. The bradykinin B2 receptor antagonist Hoe 140 affected neither PNV- nor capsaicin-induced responses. Our results suggest that PNV and capsaicin each induce paw oedema that is partially mediated by activation of sensory fibers culminating in the release of substance P as well as by activation of mast cells which in turn release amines such as histamine and 5-HT.     

Antisnake venom activity of ethanolic seed extract of Strychnos nux vomica Linn

The whole seed extract of S. nux vomica (in low doses) effectively neutralized Daboia russelii venom induced lethal, haemorrhage, defibrinogenating, PLA2 enzyme activity and Naja kaouthia venom induced lethal, cardiotoxic, neurotoxic, PLA2 enzyme activity. The seed extract potentiated polyvalent snake venom antiserum action in experimental animals. An active compound (SNVNF) was isolated and purified by thin layer chromatography and silica gel column chromatography, which effectively antagonised D. russelii venom induced lethal, haemorrhagic, defibrinogenating, oedema, PLA2 enzyme activity and N. kaouthia induced lethal, cardiotoxic, neurotoxic, PLA, enzyme activity. Polyvalent snake venom antiserum action was significantly potentiated by the active compound. Spectral studies revealed it to be a small, straight chain compound containing methyl and amide radicals. Detailed structure elucidation of the compound (SNVNF) is warranted before its clinical trials as a snake venom antagonist.     

Local inflammation,lethality and cytokine release in mice injected with Bothrops atrox venom.

We have provided evidence that: (a) lethality of mice to crude Bothrops venom varies according the isogenic strain (A/J > C57Bl/6 > A/Sn > BALB/c > C3H/HePas > DBA/2 > C3H/He); (b)BALB/c mice (LD50=100.0 microg) were injected i.p. with 50 microg of venom produced IL-6, IL-10, INF-gamma, TNF-alpha and NO in the serum. In vitro the cells from the mice injected and challenged with the venom only released IL-10 while peritoneal macrophages released IL-10, INF-gamma and less amounts of IL-6; (c) establishment of local inflammation and necrosis induced by the venom, coincides with the peaks of TNF-alpha, IFN-gamma and NO and the damage was neutralized when the venom was incubated with a monoclonal antibody against a 60 kDa haemorrhagic factor. These results suggest that susceptibility to Bothrops atrox venom is genetically dependent but MHC independent; that IL-6, IL-10, TNF-alpha, IFN-gamma and NO can be involved in the mediation of tissue damage; and that the major venom component inducers of the lesions are haemorrhagins.     

Neuromuscular action of venom from the South American colubrid snake Philodryas patagoniensis

Snakes of the opisthoglyphous genus Philodryas are widespread in South America and cause most bites by colubrids in this region. In this study, we examined the neurotoxic and myotoxic effects of venom from Philodryas patagoniensis in biventer cervicis and phrenic nerve-diaphragm preparations and we compared the biochemical activities of venoms from P. patagoniensis and Philodryas olfersii. Philodryas patagoniensis venom (40 microg/mL) had no effect on mouse phrenic nerve-diaphragm preparations but caused time-dependent neuromuscular blockade of chick biventer cervicis preparations. This blockade was not reversed by washing. The highest concentration of venom tested (40 microg/mL) significantly reduced (p<0.05) the contractures to exogenous acetylcholine (55 microM and 110 microM) and K(+) (13.4 mM) after 120 min; lower concentrations of venom had no consistent or significant effect on these responses. Venom caused a concentration- and time-dependent release of creatine kinase (CK) from biventer cervicis preparations. Histological analysis showed contracted muscle fibers at low venom concentrations and myonecrosis at high concentrations. Philodryas venoms had low esterase and phospholipase A(2) but high proteolytic activities compared to the pitviper Bothrops jararaca. SDS-PAGE showed that the Philodryas venoms had similar electrophoretic profiles, with most proteins having a molecular mass of 25-80 kDa. Both of the Philodryas venoms cross-reacted with bothropic antivenom in ELISA, indicating the presence of proteins immunologically related to Bothrops venoms. RP-HPLC of P. patagoniensis venom yielded four major peaks, each of which contained several proteins, as shown by SDS-PAGE. These results indicate that P. patagoniensis venom has neurotoxic and myotoxic components that may contribute to the effects of envenoming by this species.     

Neutralization of some hematological and hemostatic alterations induced by neuwiedase, a metalloproteinase isolated from Bothrops neuwiedi pauloensis snake venom, by the aqueous extract from Casearia mariquitensis (Flacourtiaceae)

The aqueous extract from the leaves of Casearia mariquitensis (C. m.), a plant found in Brazilian open pastures, was assayed for its ability to inhibit some hematological and hemostatic effects induced by neuwiedase, a 22 kDa class P-I metalloproteinase from the venom of the South American pit viper Bothrops neuwiedi pauloensis. The aqueous extract from C. m. was able to neutralize the hematological alterations induced by the crude venom (C.V.) upon erythrocytes when the venom was incubated at a ratio of 1:10 (w/w, venom/extract), but it did not neutralize the platelet decreasing ability of C.V. The plasma fibrinogen concentration decreased approximately 36% and 83% when 0.6 LD(50) of the C.V. or neuwiedase, respectively, were injected by i.p. route in mice, and the aqueous extract from C. m. was able to inhibit this effect. The Bbeta fibrinogen chain was protected against degradation caused by crude venom and neuwiedase when the venom or toxin were incubated with C. m. extract. We also observed that this extract exerted a very slight effect on the clotting time, prolonging it only to a little extent. The pulmonary hemorrhage induced by neuwiedase when injected intravenously with 0.6 LD(50) was completely inhibited when this toxin was incubated with the extract at a ratio of 1:10 (w/w, toxin/extract). It is concluded that C. m. displays components able to inhibit some hematological and systemic alterations induced by C.V.     

Inhibition of enzymatic and pharmacological activities of some snake venoms and toxins by Mandevilla velutina (Apocynaceae) aqueous extract

Phospholipases A(2) (PLA(2)) are multifunctional proteins which exhibit varied biological activities correlated to the structural diversities of the sub-classes. The crude aqueous extract from subterranean system of Mandevilla velutina, a plant found in Brazilian savanna, was assayed for its ability to inhibit biological activities of several snake venoms and isolated PLA(2)s. The extract induced total inhibition of the phospholipase activity of Crotalus durissus terrificus venom and only partial inhibition of Bothrops venoms. When assayed against purified toxins, the highest efficacy was detected against CB and crotoxin, while almost ineffective against PLA(2)s from the genus Bothrops. Although M. velutina crude extract significantly inhibited the myotoxic activity of C. d. terrificus venom and CB, it produced only partial inhibition of either Bothrops jararacussu venom or its main myotoxins BthTX-I (basic Lys49), BthTX-II (basic Asp49) and BthA-I-PLA(2) (acidic Asp49). The extract exhibited also full inhibition of hemorrhage caused by Bothrops alternatus, Bothrops moojeni and Bothrops pirajai snake venoms, but partial inhibition (90%) of that induced by B. jararacussu venom. The extract was ineffective to inhibit the fibrinogenolytic activity of B. moojeni, B. alternatus and B. pirajai crude venoms, while their caseinolytic activity was only partially inhibited. No inhibition of the anticoagulant activity, although partial reduction of the edema-inducing activity of C. d. terrificus and B. alternatus crude venoms, CB, PrTX-I, BthTX-I and crotoxin was observed. Besides extending survival of mice injected with lethal doses of C. d. terrificus and B. jararacussu venoms, M. velutina extract decreased to 50% the lethality of mice. Extracts of 18 month old micropropagated plants were able to partially neutralize the effect of the crude venoms and toxins.     

Leukocyte recruitment induced by snake venom metalloproteinases: Role of the catalytic domain

Snake venom metalloproteinases (SVMPs) are key toxins involved in local inflammatory reactions after snakebites. This study aimed to investigate the effect of SVMP domains on the alterations in leukocyte-endothelium interactions in the microcirculation of mouse cremaster muscle. We studied three toxins: BnP1, a PI-toxin isolated from Bothrops neuwiedi venom, which only bears a catalytic domain; Jararhagin (Jar), a PIII-toxin isolated from Bothrops jararaca venom with a catalytic domain, as well as ECD-disintegrin and cysteine-rich domains; and Jar-C, which is produced from the autolysis of Jar and devoid of a catalytic domain. All these toxins induced an increase in the adhesion and migration of leukocytes. By inhibiting the catalytic activity of Jar and BnP1 with 1.10-phenanthroline (oPhe), leukocytes were no longer recruited. Circular dichroism analysis showed structural changes in oPhe-treated Jar, but these changes were not enough to prevent the binding of Jar to collagen, which occurred through the ECD-disintegrin domain. The results showed that the catalytic domain of SVMPs is the principal domain responsible for the induction of leukocyte recruitment and suggest that the other domains could also present inflammatory potential only when devoid of the catalytic domain, as with Jar-C.     

Pharmacological characterisation of arthritis induced by Bothrops jararaca venom in rabbits: a positive cross talk between bradykinin, nitric oxide and prostaglandin E2

BACKGROUND: Our previous results showed that nitric oxide (NO) and bradykinin (BK) mediate the arthritis induced by Bothrops jararaca venom (BjV) in rabbits. In this study, we investigated the contribution of each receptor of BK as well as the inter-relationship between NO and eicosanoids in BjV-induced arthritis. METHODS: The arthritis was induced in rabbits with 16 microg of BjV injected intra-articularly. Prostaglandin E2 (PGE2), thromboxane B2 (TxB2), leukotriene B4 (LTB4) (radioimmunoassay) and nitrite/nitrate concentrations (NO2/NO3) (Griess reaction) were evaluated in the synovial fluid 4 h later. The animals were prior treated with NO synthase inhibitor (L-NAME; 20 mg/kg/day for 14 days), the B2 antagonist of BK (HOE-140) and the B1 antagonist of BK (des-Arg9[Leu8]-bradykinin), both at a dose of 0.3mg/kg, 30 min prior to the venom injection. RESULTS: Data show that L-NAME and HOE-140 treatment were equally able to reduce PGE2 and NO2/NO3 levels without interfering with TxB2 and LTB4 production. On the contrary, the B1 antagonist of BK inhibited TxB2 and LTB4 production, and did not alter PGE2 and NO metabolites levels in the inflamed joint. DISCUSSIONS: The results presented clarify the contribution of the kinin system, mainly through the B2 receptor, to the local inflammatory response induced by BjV, as well as its positive interaction with PGE2 and NO production.