Long-lasting anti-inflammatory properties of Crotalus durissus terrificus snake venom in mice

Tarantula cubensis extract (Theranekron®) ınhibits ınflammation in carrageenan-ınduced acute paw edema in rats

ABSTRACT The aim of this study was to investigate the anti-inflammatory effect of alcoholic extract of Tarantula cubensis alcoholic extract (TCAE) in experimentally induced inflammation in rats. Fifty-four adult Sprague-Dawley male rats were randomly divided into nine groups. Paw edema was induced by 0.2mL subplantar (s.p.) injection of 1% carrageenan (CAR) into the right hind paw. Rats were treated with the nonsteroidal anti-inflammatory drug (NSAID) indomethacin (INDO) (10mg/kg, p.o.) or TCAE at different doses (1, 10 or 100µg/kg) injected s.c. for systemic or s.p. for local anti-inflammatory effect. Saline was used as control. Changes in paw thickness, volume, and weight were calculated as percentages. Formalin-fixed paws were used for histopathological examination. We detected that TCAE applied s.c. at 10µg/kg and 100µg/kg doses resulted in thinner paw thickness, lower paw volume, and lower paw weights four hours after the induction of inflammation when compared with the INDO group (p<0.05). The paw edema inhibitory effect of TCAE applied at a dose of 10µg/kg, s.c. was 68% when compared with the INDO which had an inhibitory effect of 56%. These results were verified with similar histopathological findings. The anti-inflammatory feature of 10µg/kg of TCAE given systematically was similar to the effects of INDO. Our results suggest that TCAE has anti-inflammatory effects by reducing edema and decreasing inflammatory reaction. These results may be attributed to the inhibition of the production of proinflammatory mediators. Thus, TCAE may be considered as a potential anti-inflammatory agent for treating acute inflammatory conditions.

Correlating biological activity to thermo-structural analysis of the interaction of CTX with synthetic models of macrophage membranes

The important pharmacological actions of Crotoxin (CTX) on macrophages, the main toxin in the venom of Crotalus durissus terrificus, and its important participation in the control of different pathophysiological processes, have been demonstrated. The biological activities performed by macrophages are related to signaling mediated by receptors expressed on the membrane surface of these cells or opening and closing of ion channels, generation of membrane curvature and pore formation. In the present work, the interaction of the CTX complex with the cell membrane of macrophages is studied, both using biological cells and synthetic lipid membranes to monitor structural alterations induced by the protein. Here we show that CTX can penetrate THP-1 cells and induce pores only in anionic lipid model membranes, suggesting that a possible access pathway for CTX to the cell is via lipids with anionic polar heads. Considering that the selectivity of the lipid composition varies in different tissues and organs of the human body, the thermostructural studies presented here are extremely important to open new investigations on the biological activities of CTX in different biological systems.

Acute toxicity, antinociceptive, and anti-inflammatory activities of the orally administered crotamine in mice

Crotamine is a polypeptide toxin isolated from rattlesnake venom. Although several studies have been developed identifying many biological effects of isolated crotamine, none of them evaluated its acute toxicity, antinociceptive, and anti-inflammatory activities through oral administration. All in vivo experiments from this study were performed in mice. The up-and-down procedure and hippocratic screening were carried out to evaluate possible pharmacological and toxic effects. Antinociceptive and anti-inflammatory activities of this toxin were evaluated using acetic acid-induced abdominal writhing, formalin-induced pain assays, croton oil-induced ear edema, and carrageenan-induced pleurisy. Crotamine did not cause lethality or signs of intoxication up to the maximum dose tested (10.88 mg/kg). The number of contortions was reduced significantly by 34, 57, and 74% at the oral doses of 0.08, 0.16, and 0.32 mg/kg, respectively. At the dose of 0.16 mg/kg, crotamine decreases pain time-reactivity at neurogenic phase by 45% and at inflammatory phase by 60%. Also, crotamine elicited antiedematogenic activity through the attenuation of the croton oil-induced ear edema by 77%. In the carrageenan-induced pleurisy, the leukocyte, neutrophil, and mononuclear cell migration to the lesion site were reduced by 52%, 46%, and 59%, respectively. Altogether, crotamine demonstrated in vivo antinociceptive and anti-inflammatory effect through acute oral administration, generating an anti-migratory mechanism of action at non-toxic doses.

Immunotherapeutic potential of Crotoxin: anti-inflammatory and immunosuppressive properties

For the past 80 years, Crotoxin has become one of the most investigated isolated toxins from snake venoms, partially due to its major role as the main toxic component in the venom of the South American rattlesnake Crotalus durissus terrificus. However, in the past decades, progressive studies have led researchers to shift their focus on Crotoxin, opening novel perspectives and applications as a therapeutic approach. Although this toxin acts on a wide variety of biological events, the modulation of immune responses is considered as one of its most relevant behaviors. Therefore, the present review describes the scientific investigations on the capacity of Crotoxin to modulate anti-inflammatory and immunosuppressive responses, and its application as a medicinal immunopharmacological approach. In addition, this review will also discuss its mechanisms, involving cellular and molecular pathways, capable of improving pathological alterations related to immune-associated disorders.

Anti-ophidian activity of Bredemeyera floribunda Willd. (Polygalaceae) root extract on the local effects induced by Bothrops jararacussu venom

Bredemeyera floribunda roots are popularly used to treat snakebites in the semiarid region of Northeast Brazil, and previous studies indicate the anti-ophidian actions of triterpenoid saponins found in its roots. To assess B. floribunda root extract (BFRE) activity against the effects of Bothrops jararacussu venom (BjuV), antiphospholipasic, antiproteolytic, antihemorrhagic, antinecrotic, and anti-edematogenic activities were investigated in mice. Phytochemical analysis revealed the presence of saponins, flavonoids, and sugars, with rutin and saccharose being the major constituents of BFRE. Acute toxicity was determined and BFRE was nontoxic to mice. Phospholipase A2 and proteolytic activities induced by BjuV were inhibited in vitro by BFRE at all concentrations tested herein. BFRE (150 mg/kg) inhibited paw edema induced by BjuV (50 µg/animal), reducing total edema calculated by area under the curve, but carrageenan-induced paw edema was unchanged. Hemorrhagic and necrotizing actions of BjuV (50 µg/animal) were considerably decreased by BFRE treatment. Thus, BFRE blocked the toxic actions of B. jararacussu venom despite having no anti-inflammatory activity, which points to a direct inhibition of venom's toxins, as demonstrated in the in vitro assays. The larger amounts of rutin found in BFRE may play a role in this inhibition, since 3',4'-OH flavonoids are known inhibitors of phospholipases A2.

Evaluation of pro-inflammatory events induced by Bothrops alternatus snake venom

Inflammation is a major local feature of envenomation by bothropic snakes being characterized by a prominent local edema, pain, and extensive swelling. There are reports demonstrating that whole Bothrops snake venoms and toxins isolated from them are able to activate macrophages functions, such as phagocytosis, production of reactive oxygen, cytokines and eicosanoids, however, little is known about the effects of Bothrops alternatus (B.a.) venom on macrophages. In this work, we evaluated the proinflammatory effects of B.a. venom with in vivo and in vitro experiments using the Raw 264.7 cell line and mouse peritoneal macrophages. We detected that B.a. venom augments cell permeability (2-fold), and cellular extravasation (mainly neutrophils), increase proinflammatory cytokines IL1 (∼300-fold), IL12 (∼200-fold), and TNFα (∼80-fold) liberation and induce the expression of enzymes related to lipid signaling, such as cPLA_2α and COX-2. Additionally, using lipidomic techniques we detected that this venom produces a release of arachidonic acid (∼10 nMol/mg. Protein) and other fatty acids (16:0 and 18:1 n-9c). Although much of these findings were described in inflammatory processes induced by other bothropic venoms, here we demonstrate that B.a. venom also stimulates pro-inflammatory pathways involving lipid mediators of cell signaling. In this sense, lipidomics analysis of macrophages stimulated with B.a. venom evidenced that the main free fatty acids are implicated in the inflammatory response, and also demonstrated that this venom, is able to activate lipid metabolism even with a low content of PLA₂.

Origin and characterization of small membranous vesicles present in the venom of Crotalus durissus terrificus

Small membranous vesicles are small closed fragments of membrane. They are released from multivesicular bodies (exosomes) or shed from the surface membrane (microvesicles). They contains various bioactive molecules and their molecular composition varies depending on their cellular origin. Small membranous vesicles have been identified in snake venoms, but the origin of these small membranous vesicles in the venom is controversial. The aim of this study was to verify the origin of the small membranous vesicles in venom of Crotalus durissus terrificus by morphological analyses using electron microscopy. In addition, the protein composition of the vesicles was analyzed by using a proteome approach. The small membranous vesicles present in the venom were microvesicles, since they originated from microvilli on the apical membrane of secretory cells. They contained cytoplasmic proteins, and proteins from the plasma membrane, endoplasmic reticulum (ER), and Golgi membrane. The release of microvesicles may be a mechanism to control the size of the cell membrane of the secretory cells after intense exocytosis. Microvesicle components that may have a role in envenoming include ecto-5'-nucleotidase, a cell membrane protein that releases adenosine, and aminopeptidase N, a cell membrane protein that may modulate the action of many peptides.

Vitamin D Modulates Hematological Parameters and Cell Migration into Peritoneal and Pulmonary Cavities in Alloxan-Diabetic Mice

Background/Aims. The effects of cholecalciferol supplementation on the course of diabetes in humans and animals need to be better understood. Therefore, this study investigated the effect of short-term cholecalciferol supplementation on biochemical and hematological parameters in mice. Methods. Male diabetic (alloxan, 60 mg/kg i.v., 10 days) and nondiabetic mice were supplemented with cholecalciferol for seven days. The following parameters were determined: serum levels of 25-hydroxyvitamin D, phosphorus, calcium, urea, creatinine, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, red blood cell count, white blood cell count (WBC), hematocrit, hemoglobin, differential cell counts of peritoneal lavage (PeL), and bronchoalveolar lavage (BAL) fluids and morphological analysis of lung, kidney, and liver tissues. Results. Relative to controls, cholecalciferol supplementation increased serum levels of 25-hydroxyvitamin D, calcium, hemoglobin, hematocrit, and red blood cell counts and decreased leukocyte cell counts of PeL and BAL fluids in diabetic mice. Diabetic mice that were not treated with cholecalciferol had lower serum calcium and albumin levels and hemoglobin, WBC, and mononuclear blood cell counts and higher serum creatinine and urea levels than controls. Conclusion. Our results suggest that cholecalciferol supplementation improves the hematological parameters and reduces leukocyte migration into the PeL and BAL lavage of diabetic mice.

New immunization protocol to produce crotalic antivenom combining Crotalus durissus terrificus venom and its PLA2

Antivenoms are usually obtained by animal immunization with successive inoculations of increasing sublethal amounts of venom, which may impair the animal health. The high lethality of venom requires prolonged immunization plans with small amounts of venom. Thus, we propose an alternative plan that includes a pre-immunization of the animal with phospholipase A2, the main crotoxin component, which is responsible for the whole venom lethality. For comparison, three different immunization schemes were designed: high dose protocol (HDP; 0.5-27 mg of venom), low dose protocol (LDP; 0.1-7 mg of venom) and Mix protocol (MP; preimmunization 0.1-1.2 mg of crotalic PLA2, and then 4.5-8 mg of venom). Antibody titers were determined by ELISA, in blood plasma obtained from the marginal vein of the ear. The neutralizing ability of the different sera obtained by all protocols (HDS, LDS and MS) was tested against the most important pharmacological activities of whole venom: PLA2 activity, myotoxicity, thrombin like activity and lethality. MS showed the best neutralizing efficacy and at the same time, it was obtained by an immunization protocol that takes account of animal health care, since it requires low quantities of venoms in comparison to traditional protocols.

Taiwan cobra phospholipase A2 suppresses ERK-mediated ADAM17 maturation, thus reducing secreted TNF-α production in human leukemia U937 cells

The goal of this study was to explore the signaling pathway regulating the processing of proADAM17 into ADAM17 in Taiwan cobra phospholipase A2 (PLA2)-treated human leukemia U937 cells. PLA2 induced reactive oxygen species (ROS)-elicited p38 MAPK activation and ERK inactivation in U937 cells. Catalytically inactive bromophenacylated PLA2 (BPB-PLA2) and PLA2 mutants evoked Ca(2+)-mediated p38 MAPK activation, and the level of phosphorylated ERK remained unchanged. PLA2 treatment reduced mature ADAM17 expression and secreted TNF-α (sTNF-α) production. Co-treatment of SB202190 (p38 MAPK inhibitor) and catalytically inactive PLA2 increased ERK phosphorylation, ADAM17 maturation and sTNF-α production. Nevertheless, mRNA levels of ADAM17 and TNF-α were insignificantly altered after PLA2 and SB202190/BPB-PLA2 treatment. ADAM17 activity assay and knock-down of ADAM17 revealed that ADAM17 was involved in sTNF-α production. Restoration of ERK activation increased the processing of proADAM17 into ADAM17 in PLA2-treated cells, while inactivation of ERK reduced ADAM17 maturation in untreated and SB202190/BPB-PLA2-treated cells. Removal of cell surface heparan sulfate abrogated PLA2 and SB202190/BPB-PLA2 effect on ADAM17 maturation. Taken together, the present data reveal that PLA2 suppresses ERK-mediated ADAM17 maturation, thus reducing sTNF-α production in U937 cells. Moreover, the binding with heparan sulfate is crucial for the PLA2 effect.

Pharmacological characterization of Solanum cernuum Vell.: 31-norcycloartanones with analgesic and anti-inflammatory properties

Cycloeucalenone (1) and 24-oxo-31-norcycloartanone (2) obtained from Solanum cernuum Vell. were assayed to explore their pharmacologic roles. Previous studies showed that (2) has selective activity against lung tumor cell line (NCIH460) which expresses high levels of COX-2, suggesting its role in inflammatory process, and also a link between chronic inflammation and cancer-associated process. Dichloromethane crude extract (DCE) significantly reduced writhing and stretching induced by 0.8 % acetic acid at a dose of 100, 300, and 600 mg/kg, po; oral administration of different doses of (1) and (2) also displayed significant analgesic and anti-inflammatory effects in the writhing acetic acid test (p < 0.0001). Selected oral doses of both compounds (100 and 50 mg/kg) were assayed in the carrageenan-induced paw edema model. Compound (2) showed significant activity during the early phase (1.5-6 h) and also in the late phase (48 h) (p < 0.01). The anti-nociceptive activity observed for the compounds (1) and (2) and DCE was found to be related to the inhibition of different mediators involved in inflammation and nociceptive process. Both compounds decrease COX-2 protein expression, although only compound (2) reached a significant response (p < 0.05 vs control). However, in vitro Sirtuin 1 activity and TNF-α production in THP-1 macrophages were not affected.

Antinociceptive and anti-inflammatory effects of orally administrated denatured naja naja atra venom on murine rheumatoid arthritis models

To investigate the antinociceptive and anti-inflammatory activities of the denatured Naja Naja atra venom (NNAV) in rheumatoid arthritis-associated models, the denatured NNAV (heat treated; 30, 90, 270 μg/kg), the native NNAV (untreated with heat; 90 μg/kg), and Tripterygium wilfordii polyglycoside (TWP, 15 mg/kg) were administrated orally either prophylactically or therapeutically. We measured time of licking the affected paw in formaldehyde-induced inflammatory model, paw volume in egg-white-induced inflammation, and granuloma weight in formalin-soaked filter paper-induced granuloma. For adjuvant-induced arthritis (AIA) rats, paw edema, mechanical withdrawal threshold, serum levels of TNF-α and IL-10, and histopathological changes of the affected paw were assessed. We found that the denatured NNAV (90, 270 μg/kg) significantly reduced time of licking paw, paw volume, and granuloma weight in above inflammatory models and also attenuated paw edema, mechanical hyperalgesia, and histopathology changes in AIA rats. Additionally, the increase in serum TNF-α and the decrease in serum IL-10 in AIA rats were reversed by the denatured NNAV. Although the native NNAV and TWP rendered the similar pharmacological actions on the above four models with less potency than that of the denatured NNAV, these findings demonstrate that oral administration of the denatured NNAV produces antinociceptive and anti-inflammatory activities on rheumatoid arthritis.

Inhibitory effect of Crotalus durissus terrificus venom on chronic edema induced by injection of bacillus Calmette-Guérin into the footpad of mice

In this study, we evaluated the effect of the Crotalus durissus terrificus (Cdt) venom on the chronic paw edema induced by the injection of bacillus Calmette-Guérin (BCG) into the footpad of mice. The BCG injection evoked chronic edema, which was significantly diminished in animals treated subcutaneously (s.c.) with Cdt venom 1 h before or after the BCG injection. This inhibition persisted throughout the evaluation period (15 days). In mice injected with Cdt venom 6 or 11 days after injection of BCG, we observed a significant reduction in edema only in the period after the venom injection. While studying possible mechanisms involved in this inhibition, we observed that pre-treatment with dexamethasone, zileuton or Boc2 (a selective antagonist of formyl peptide receptors), but not with indomethacin, canceled out the inhibitory effect of Cdt venom on the edema induced by BCG. These results strongly suggest that this rattlesnake venom can stimulate the generation of mediators from the lipoxygenase pathway, which can down-regulate this chronic inflammatory edema. Using fractionated venom, the results indicated that crotoxin was the only component of Cdt venom responsible for this inhibitory effect. These results indicated that crotoxin, the main toxin of the C. durissus terrificus venom, has a significant inhibitory effect on BCG-induced chronic edema, possibly by generating anti-inflammatory mediators from the lipoxygenase pathway.

Crotoxin, a rattlesnake toxin, induces a long-lasting inhibitory effect on phagocytosis by neutrophils

Crotalus durissus terrificus snake venom (CdtV) has long-lasting anti-inflammatory properties and inhibits the spreading and phagocytic activity of macrophages. Crotoxin (CTX), the main component of CdtV, is responsible for these effects. Considering the role of neutrophils in the inflammatory response and the lack of information about the effect of CdtV on neutrophils, the aim of this study was to investigate the effect of CdtV and CTX on two functions of neutrophils, namely phagocytosis and production of reactive oxygen species, and on the intracellular signaling involved in phagocytosis, particularly on tyrosine phosphorylation and rearrangements of the actin cytoskeleton. Our results showed that the incubation of neutrophils with CdtV or CTX, at different concentrations, or the subcutaneous injection of CdtV or CTX in rats two hours or one, four or 14 days before or one hour after the induction of inflammation inhibited the phagocytic activity of neutrophils. Furthermore, these in vitro and in vivo effects were associated with CdtV and CTX inhibition of tyrosine phosphorylation and consequently actin polymerization. Despite the inhibitory effect on phagocytosis, this study demonstrated that CdtV and CTX did not alter the production of the main reactive oxygen species. Therefore, this study characterized, for the first time, the actions of CdtV on neutrophils and demonstrated that CTX induces a long-lasting inhibition of tyrosine phosphorylation and consequently phagocytosis. We suggest that CTX represents a potential natural product in controlling inflammatory diseases, since a single dose exerts a long-lasting effect on intracellular signaling involved in phagocytosis by neutrophils.

Envenomations by Bothrops and Crotalus snakes induce the release of mitochondrial alarmins

Skeletal muscle necrosis is a common manifestation of viperid snakebite envenomations. Venoms from snakes of the genus Bothrops, such as that of B. asper, induce muscle tissue damage at the site of venom injection, provoking severe local pathology which often results in permanent sequelae. In contrast, the venom of the South American rattlesnake Crotalus durissus terrificus, induces a clinical picture of systemic myotoxicity, i.e., rhabdomyolysis, together with neurotoxicity. It is known that molecules released from damaged muscle might act as ‘danger’ signals. These are known as ‘alarmins’, and contribute to the inflammatory reaction by activating the innate immune system. Here we show that the venoms of B. asper and C. d. terrificus release the mitochondrial markers mtDNA (from the matrix) and cytochrome c (Cyt c) from the intermembrane space, from ex vivo mouse tibialis anterior muscles. Cyt c was released to a similar extent by the two venoms whereas B. asper venom induced the release of higher amounts of mtDNA, thus reflecting hitherto some differences in their pathological action on muscle mitochondria. At variance, injection of these venoms in mice resulted in a different time-course of mtDNA release, with B. asper venom inducing an early onset increment in plasma levels and C. d. terrificus venom provoking a delayed release. We suggest that the release of mitochondrial ‘alarmins’ might contribute to the local and systemic inflammatory events characteristic of snakebite envenomations.

Every year, hundreds of thousands of people in tropical and sub-tropical areas of the world are bitten by poisonous snakes and may develop permanent damages. This is a major tropical disease which is largely neglected by scientific and clinical investigators. Snakes of Bothrops and Crotalus genus are responsible of most cases in Latin America. Here for the first time, we have shown that these venoms cause the release of both mitochondrial DNA and cytochrome c, two well known alarmins. Moreover, the kinetic of these processes are in agreement with the different pathophysiological profiles exhibited by Bothrops and Crotalus envenomations. These elements suggest a correlation between snake evenomations and sterile inflammatory syndrome. Alarmins are reported to have a fundamental role in innate immune response and inflammation; they might contribute to the local and systemic inflammatory events characteristic of these envenomations opening a new prospective in the study of these complex pathologies.

Involvement of cholinergic system in suppression of formalin-induced inflammatory pain by cobratoxin

AIM

To investigate the analgesic effect of cobratoxin (CTX), a long-chain α-neurotoxin from Thailand cobra venom, in a rat model of formalin-induced inflammatory pain.

METHODS

Inflammatory pain was induced in SD rats via injecting 5% formalin (50 μL) into the plantar surface of their right hind paw. CTX and other agents were ip administered before formalin injection. The time that the animals spent for licking the injected paw was counted every 5 min for 1 h.

RESULTS

CTX (25, 34, and 45 μg/kg) exhibited a dose-dependent analgesic effect during the phase 1 (0-15 min) and phase 2 (20-60 min) response induced by formalin. Pretreatment with naloxone (0.5 or 2.5 mg/kg) did not block the analgesic effect of CTX. Pretreatment with atropine at 5 mg/kg, but not at 2.5 mg/kg, antagonized the analgesic effect of CTX. Treatment with the nonselective nAChR antagonist mecamylamine (3 mg/kg) inhibited the analgesic effects of CTX in Phase 1 and Phase 2 responses, while with the selective α7-nAChR antagonist methyllycaconitine (3 mg/kg) antagonized the effect of CTX only in the Phase 1 response. Treatment with the α7-nAChR agonist PNU282987 (3 mg/kg) significantly reduced the formalin-induced phase 2 pain response, but only slightly reduced the Phase 1 pain response.

CONCLUSION

The results suggest that CTX exerts an antinociceptive effect in formalin-induced inflammatory pain, which appears to be mediated by mAChR and α7-nAChR.

Inflammatory effects of patagonfibrase, a metalloproteinase from Philodryas patagoniensis (Patagonia Green Racer; Dipsadidae) venom

Patagonfibrase is a P-III class metalloproteinase isolated from the venom of Philodryas patagoniensis, a South-American, rear-fanged 'colubrid' snake responsible for accidents with clinical significance. Since local inflammatory reactions are conspicuous signs of snakebites inflicted by this species and taking into consideration that most snake venom metalloproteinases exhibit inflammatory activity, this study deals with the proinflammatory effects evoked by patagonfibrase. Herein, we demonstrate that patagonfibrase causes a time- and dose-dependent hemorrhagic edema when injected into mouse hind paws. The peak of edema occurred at 30 min after injection, and the minimum edematogenic dose was 0.021 μg. By histological analysis, the presence of moderate to marked edema and hemorrhage, and a mild inflammatory infiltrate was observed. When injected subcutaneously into the scrotal bag of mice, patagonfibrase induced cell recruitment with a significant alteration in physiological parameters of leukocyte-endothelium interaction. The presence of 1 mmol/L o-phenanthroline, which chelates metal ions, significantly inhibited the proinflammatory effects induced by patagonfibrase. Taken together, these results imply that patagonfibrase is an important contributor to local inflammation elicited by P. patagoniensis envenomation, which may pave the way for novel therapeutic strategies to treat this snakebite. Moreover, our findings demonstrate for the first time that a venom metalloproteinase from a rear-fanged snake elicits proinflammatory effects mainly mediated by its catalytic activity.

Effect of goniothalamin on the development of Ehrlich solid tumor in mice

In this work the antiproliferative activity of goniothalamin (1), both in racemic and in its enantiomeric pure forms, in a solid tumor experimental model using laboratory animals is described. The antiedematogenic activity displayed by racemic 1 in the carrageenan edema model in mice together with the reduction of Ehrlich solid tumor model suggest a relationship between anticancer and antiinflammatory activities with the antiinflammatory activity favoring the antiproliferative activity itself.

Crotoxin is responsible for the long-lasting anti-inflammatory effect of Crotalus durissus terrificus snake venom: involvement of formyl peptide receptors

In the present study, it was investigated which components are responsible for the anti-inflammatory properties of Crotalus durissus terrificus venom (CdtV). The effect of crotoxin, as well as of other CdtV components was evaluated on edema, cell migration and alterations in leukocyte-endothelium interactions induced by carrageenan. Crotoxin (40 microg kg(-1)) was injected at different time periods before or after the injection of carrageenan (15 mg kg(-1)) into the mouse hind paw, peritoneum or scrotum. Results showed that crotoxin, but not other CdtV components, significantly inhibited inflammatory edema and cell migration when administered before or after carrageenan injection in mice. This toxin also prevented the occurrence of alterations in leukocyte-endothelium interactions induced by carrageenan injection, such as the increase in adhered cells. In animals pretreated with Boc2 (a selective antagonist of formyl peptide receptors), crotoxin showed neither inhibitory effects on edema and cell migration, nor prevented alterations in leukocyte-endothelium interactions induced by carrageenan. These findings demonstrate that crotoxin is the component responsible for the long-lasting anti-inflammatory activity of crude C. durissus terrificus venom, and activation of formyl peptide receptors seems to play a major role in this effect.

Suppression of complete Freund's adjuvant-induced adjuvant arthritis by cobratoxin

AIM

Cobratoxin (CTX), the long-chain alpha-neurotoxin from Thailand cobra venom, has been demonstrated to have analgesic action in rodent pain models. The present study evaluated the anti-inflammatory and anti-nociceptive effects of CTX on adjuvant arthritis (AA) in rats.

METHODS

Arthritis was induced by injection of complete Freund's adjuvant (CFA) in rats. Paw swelling and hyperalgesia of AA rats were measured at various times after CFA administration. Tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-2 (IL-2) and interleukin-10 (IL-10) levels in serum were determined with ELISA. Histopathological changes in synoviocytes were examined under a microscope. Involvement of the cholinergic system in the effects of CTX was examined by pretreatment of animals with the alpha(7) nicotinic receptor (alpha(7)-nAChR) antagonist methyllycaconitine (MLA).

RESULTS

CFA induced marked paw swelling and reduced thresholds of mechanical and cold-induced paw withdrawal. The levels of TNF-alpha, IL-1 and IL-2 in the serum of AA rats were increased, whereas the level of IL-10 was decreased. Histopathological examination of synoviocytes showed pronounced inflammation and accumulation of collagen. The administration of CTX (17.0 microg/kg, ip) significantly reduced paw swelling and mechanical and thermal hyperalgesia. CTX also reduced the production of TNF-alpha, IL-1, and IL-2 but increased the production of IL-10 and altered pathohistological changes. The analgesic and anti-inflammatory efficacy of CTX was significantly reduced by MLA (3 mg/kg, sc).

CONCLUSION

These results indicate that CTX has a beneficial effect on CFA-induced arthritis by modulating the production of inflammatory cytokines. alpha(7)-nAChR appears to mediate the anti-nociceptive and anti-inflammatory actions of CTX.