Atrox Venom Research Articles

The Contrasting Effects of Bothrops lanceolatus and Bothrops atrox Venom on Procoagulant Activity and Thrombus Stability under Blood Flow Conditions.

Consumption coagulopathy and hemorrhagic syndrome are the typical features of Bothrops sp. snake envenoming. In contrast, B. lanceolatus envenoming can induce thrombotic complications. Our aim was to test whether crude B. lanceolatus and B. atrox venoms would display procoagulant activity and induce thrombus formation under flow conditions. Fibrin formation in human plasma was observed for B. lanceolatus venom at 250-1000 ng/mL concentrations, which also induced clot formation in purified human fibrinogen, indicating thrombin-like activity. The degradation of fibrinogen confirmed the fibrinogenolytic activity of B. lanceolatus venom. B. lanceolatus venom displayed consistent thrombin-like and kallikrein-like activity increases in plasma conditions. The well-known procoagulant B. atrox venom activated plasmatic coagulation factors in vitro and induced firm thrombus formation under high shear rate conditions. In contrast, B. lanceolatus venom induced the formation of fragile thrombi that could not resist shear stress. Our results suggest that crude B. lanceolatus venom displays amidolytic activity and can activate the coagulation cascade, leading to prothrombin activation. B. lanceolatus venom induces the formation of an unstable thrombus under flow conditions, which can be prevented by the specific monovalent antivenom Bothrofav®.

Sex-related differences in toxic manifestations induced by Bothrops atrox venom in mice

Lancehead snakes of the genus Bothrops are responsible for 90% of the snakebites in Latin America. The objective of this study was to assess the LD50, physical, and hematological manifestations induced by B. atrox venom in male and female mice inoculated by different routes. B. atrox venom was inoculated in male and female mice by intramuscular (IM), subcutaneous (SC), intravenous (IV), and intraperitoneal (IP) routes. B. atrox venom LD50 was lower in male than female groups, regardless of the injection route. However, it was the lowest when the venom was inoculated by the IP route. Moreover, comparisons between male and female responses according to the injected venom dose showed higher edema-forming, local hemorrhagic, dermonecrotic, and myotoxic activities in male than in female mice. While the minimal hemorrhagic, and necrotic doses were not statistically different between the two groups, the difference between males and females was more pronounced at high venom doses. Hematological parameter changes were also more significant in male than in female mice. The venom decreased the levels of total leukocytes after 24 h of injection in male and female mice, with a more profound decrease in the male group. The micronucleus test, a tool for genotoxicity assessment, documented the mutagenic effects of B. atrox on leucocytes. We demonstrate the higher susceptibility of male mice to B. atrox venom than females. Sex differences must be considered when conducting experimental studies on snake venoms.

Phosphate-Buffered Saline and Dimethyl Sulfoxide Enhance the Antivenom Action of Ruthenium Chloride against Crotalus atrox Venom in Human Plasma-A Preliminary Report.

Ruthenium chloride (RuCl3) is widely utilized for synthesis and catalysis of numerous compounds in academia and industry and is utilized as a key molecule in a variety of compounds with medical applications. Interestingly, RuCl3 has been demonstrated to modulate human plasmatic coagulation and serves as a constituent of a compounded inorganic antivenom that neutralizes the coagulopathic effects of snake venom in vitro and in vivo. Using thrombelastography, this investigation sought to determine if RuCl3 inhibition of the fibrinogenolytic effects of Crotalus atrox venom could be modulated by vehicle composition in human plasma. Venom was exposed to RuCl3 in 0.9% NaCl, phosphate-buffered saline (PBS), or 0.9% NaCl containing 1% dimethyl sulfoxide (DMSO). RuCl3 inhibited venom-mediated delay in the onset of thrombus formation, decreased clot growth velocity, and decreased clot strength. PBS and DMSO enhanced the effects of RuCl3. It is concluded that while a Ru-based cation is responsible for significant inhibition of venom activity, a combination of Ru-based ions containing phosphate and DMSO enhances RuCl3-mediated venom inhibition. Additional investigation is indicated to determine what specific Ru-containing molecules cause venom inhibition and what other combinations of inorganic/organic compounds may enhance the antivenom effects of RuCl3.

Evaluation of the Inhibitory Potential of Synthetic Peptides Homologous to CDR3 Regions of a Monoclonal Antibody against Bothropic Venom Serine Proteases.

Snakebite accidents, neglected tropical diseases per the WHO, pose a significant public health threat due to their severity and frequency. Envenomation by Bothrops genus snakes leads to severe manifestations due to proteolytic enzymes. While the antibothropic serum produced by the Butantan Institute saves lives, its efficacy is limited as it fails to neutralize certain serine proteases. Hence, developing new-generation antivenoms, like monoclonal antibodies, is crucial. This study aimed to explore the inhibitory potential of synthetic peptides homologous to the CDR3 regions of a monoclonal antibody targeting a snake venom thrombin-like enzyme (SVTLE) from B. atrox venom. Five synthetic peptides were studied, all stable against hydrolysis by venoms and serine proteases. Impressively, four peptides demonstrated uncompetitive SVTLE inhibition, with Ki values ranging from 10-6 to 10-7 M. These findings underscore the potential of short peptides homologous to CDR3 regions in blocking snake venom toxins, suggesting their promise as the basis for new-generation antivenoms. Thus, this study offers potential advancements in combatting snakebites, addressing a critical public health challenge in tropical and subtropical regions.

Ruthenium-based antivenom attenuates Crotalus atrox venom mediated coagulopathy in rabbits.

The Western diamondback rattlesnake ( Crotalus atrox ) is a medically important venomous snake in the Southwestern United States, injuring humans, and their companion animals. The goals of this investigation were to utilize a rabbit model of subcutaneous envenomation to assess Crotalus atrox venom coagulopathy and determine the efficacy of a ruthenium-containing antivenom (RA) in attenuating it. Sedated New Zealand White rabbits had viscoelastic measurements of whole blood coagulation kinetics obtained from ear artery samples. Crotalus atrox venom (4 mg/kg) was injected subcutaneously and changes in coagulation determined over three hours and compared to samples obtained prior to envenomation. Other rabbits had site-directed RA injected 5 min after venom injection. A significant decrease in the velocity of clot growth and thrombus strength was observed in animals injected with venom alone. Site-directed administration of RA resulted in no change in coagulation over the 3 h following venom injection. The interaction of antivenom administration and time was significantly different in the cases of clot growth velocity and strength. A novel rabbit model was used to define the toxicodynamic profile of coagulopathy of Crotalus atrox venom and demonstrate the efficacy of RA. Future investigation is planned involving other medically important venoms and RA administration.

Primary recovery strategies of low‐molecular‐weight toxins from Crotalus molossus nigrescens and Crotalus atrox using aqueous two‐phase and three‐phase partition systems

AbstractBACKGROUNDRattlesnake venoms are a complex source of different toxin families with biotechnological and biomedical applications. However, the complexity of the sample and the low abundance of some toxins can restrict their study and applications. Toxin isolation usually requires multiple chromatographic steps, implying elevated operative costs and processing times. This raises the need for recovery and enrichment of those proteins and peptides. For that reason, we tested two liquid–liquid separation methods – aqueous two‐phase systems (ATPS) and three‐phase partition (TPP) – since these two alternatives have shown great potential for the primary recovery of different toxin families from rattlesnake venoms.RESULTSPolyethylene glycol (PEG)–citrate and ionic liquid (IL)–potassium phosphate ATPS and TPP based on t‐butanol and ammonium sulfate were used to partition different toxin families from Crotalus molossus nigrescens and C. atrox venoms. PEG–citrate allowed a selective partition of proteins between both phases. The best enrichment case was observed with a myotoxin band (6.6 kDa) in the PEG‐rich phase from 2% to 41.3% of abundance. In IL–potassium phosphate systems, proteins showed a preference towards the IL‐rich phase with no selective partition. In TPP, proteins were partitioned mainly to the bottom phase and interphase, but serine proteases (29.1 kDa) were enriched from 3.7% to 56.6% in the top phase.CONCLUSIONThe present study demonstrated that PEG–citrate ATPS and TPP separation methods can generate a selective partition of some toxin families from rattlesnake venoms. These enrichment methods will facilitate the isolation of toxins, from animal venoms, that are relevant for biotechnological and biomedical applications. © 2024 Society of Chemical Industry (SCI).

Bothrops venom-induced hemostasis disorders in the rat: Between Scylla and Charybdis.

Hemostasis impairment represents the most threatening consequence of Viperidae envenoming, notably with Bothrops genus. In the French departments of America, B. atrox envenomation in French Guiana may lead to bleeding while B. lanceolatus envenomation in Martinique to thrombosis. Bleeding related to B. atrox envenomation is attributed to vascular damage mediated by venom metalloproteinases and blood uncoagulable state resulting from thrombocytopenia and consumptive coagulopathy. Thrombosis related to B. lanceolatus envenomation are poorly understood. We aimed to compare the effects of B. atrox and B. lanceolatus venoms in the rat to identify the determinants of the hemorrhagic versus thrombotic complications. Viscoelastometry (ROTEM), platelet count, plasma fibrinogen, thrombin generation assay, fibrinography, endothelial (von Willebrand factor, ADAMTS13 activity, ICAM-1, and soluble E-selectin), and inflammatory biomarkers (IL-1β, IL-6, TNF-α, MCP-1, and PAI-1) were determined in blood samples obtained at H3, H6, and H24 after the subcutaneous venom versus saline injection. In comparison to the control, initial fibrinogen consumption was observed with the two venoms while thrombocytopenia and reduction in the clot amplitude only with B. atrox venom. Moreover, we showed an increase in thrombin generation at H3 with the two venoms, an increase in fibrin generation accompanied with hyperfibrinogenemia at H24 and an increase in inflammatory biomarkers with B. lanceolatus venom. No endothelial damage was found with the two venoms. To conclude, our data support two-sided hemostasis complications in Bothrops envenoming with an initial risk of hemorrhage related to platelet consumption and hypocoagulability followed by an increased risk of thrombosis promoted by the activated inflammatory response and rapid-onset fibrinogen restoration.

Bothrops atrox and Bothrops lanceolatus Venoms In Vitro Investigation: Composition, Procoagulant Effects, Co-Factor Dependency, and Correction Using Antivenoms.

Bothrops venoms are rich in enzymes acting on platelets and coagulation. This action is dependent on two major co-factors, i.e., calcium and phospholipids, while antivenoms variably neutralize venom-related coagulopathy effects. Our aims were (i) to describe the composition of B. atrox and B. lanceolatus venoms; (ii) to study their activity on the whole blood using rotational thromboelastometry (ROTEM); (iii) to evaluate the contribution of calcium and phospholipids in their activity; and (iv) to compare the effectiveness of four antivenoms (Bothrofav™, Inoserp™ South America, Antivipmyn™ TRI, and PoliVal-ICP™) on the procoagulant activity of these two venoms. Venom composition was comparable. Both venoms exhibited hypercoagulant effects. B. lanceolatus venom was completely dependent on calcium but less dependent on phospholipids than B. atrox venom to induce in vitro coagulation. The four antivenoms neutralized the procoagulant activity of the two venoms; however, with quantitative differences. Bothrofav™ was more effective against both venoms than the three other antivenoms. The relatively similar venom-induced effects in vitro were unexpected considering the opposite clinical manifestations resulting from envenomation (i.e., systemic bleeding with B. atrox and thrombosis with B. lanceolatus). In vivo studies are warranted to better understand the pathophysiology of systemic bleeding and thrombosis associated with Bothrops bites.

Venom Peptides of Crotalus atrox Against SARS-Cov-2 Spike Protein and Human ACE2 Receptor by Molecular Docking Analysis

Venoms are composed of about 100 to 500 pharmacologically active compounds. Less than 0.01% of these compounds have been identified and a significant majority of them act on unknown receptors. Here, the potential Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) activities of selected Crotalus atrox venom peptides (CVPs) including Atrolysin D (AD), vascular apoptosis-inducing protein-1 (VAIP-1), Catrocollastatin (CC), and Calcium-Free Phospholipase A2 (CFP) were investigated via molecular docking analysis. CVPs were docked against human angiotensin-converting enzyme-2 (ACE-2) and 3-chymotrypsin-like protease (3CLpro) viral spike protein. All CVPs had low binding energies to both 3CLpro and ACE2, suggesting that they interacted strongly with the active sites of enzymes, compared to the reference drugs lopinavir and ritonavir. The binding energy of 3CLpro was -139.517 kcal/mol, -96.239 kcal/mol, -121.590 kcal/mol, -259.424 kcal/mol with AD, VAIP-1, CC, and CFP, respectively. CFP showed a very strong binding activity with 3CLpro, suggesting that it could be a very effective compound in inhibiting the SARS-CoV-2 virus. The binding energy of ACE2 was -101.165 kcal/mol, -73.064 kcal/mol, -106.918 kcal/mol, -82.830 kcal/mol with AD, VAIP-1, CC, and CFP, respectively. AD made a much stronger bond with ACE2 than reference drugs, showing that it could be used as a virus-protective component in humans. The results suggest a potential drug candidate for the development of therapeutics against Coronavirus disease 2019 (COVID-19). In vitro and in vivo experiments are needed to confirm these compounds' potential preventive and therapeutic effects.

Bothrops atrox venom: Biochemical properties and cellular phenotypes of three highly toxic classes of toxins

Snake venoms have a complex mixture of compounds that are conserved across species and act synergistically, triggering severe local and systemic effects. Identification of the toxin classes that are most damaging to cell homeostasis would be a powerful approach to focus on the main activities that underpin envenomation. Here, we focus on the venom of Bothrops atrox, snake responsible for most of the accidents in Amazon region of South America. We identified the key cytotoxic toxin fractions from B. atrox venom and mapped their biochemical properties, protein composition and cell damage. Five fractions were obtained by mass exclusion chromatography and contained either a single class of enzymatic activity (i.e., L-amino acid oxidases or Hyaluronidases) or different activities co-distributed in two or more protein fractions (e.g., Metalloproteinases, Serine Proteases, or Phospholipases A2). Only three protein fractions reduced cell viability of primary human cells. Strikingly, such activity is accompanied by disruption of cell attachment to substratum and to neighbouring cells. Such strong perturbation of morphological cell features indicates likely defects in tissue integrity in vivo. Mass spectrometry identified the main classes of toxins that contribute to these phenotypes. We provide here a strategy for the selection of key cytotoxic proteins for targeted investigation of their mechanism of action and potential synergism during snakebite envenomation. Our data highlights putative toxins (or combinations of) that may be the focus of future therapeutic interference.

Intracellular Zinc Trafficking during Crotalus atrox Venom Wound Development.

In this study, we examined zinc trafficking in human umbilical vein endothelial cells (HUVEC) stimulated with Crotalus atrox (CA venom) snake venom. We utilized MTS cytotoxicity assays to monitor the cytotoxic range of CA venom. HUVEC monolayers stimulated with 10 µg/mL CA venom for 3 h displayed cellular retraction, which coincided with 53.0 ± 6.5 percent viability. In contrast, venom concentrations of 100 µg/mL produced a complete disruption of cellular adherence and viability decreased to 36.6 ± 1.0. The zinc probe Fluozin-3AM was used to detect intracellular zinc in non-stimulated controls, HUVEC stimulated with 10 µg/mL CA venom or HUVEC preincubated with TPEN for 2 h then stimulated with 10 µg/mL CA venom. Fluorescent intensity analysis returned values of 1434.3 ± 197.4 for CA venom demonstrating an increase of about two orders of magnitude in labile zinc compared to non-stimulated controls. Endothelial response to CA venom induced a 96.1 ± 3.0- and 4.4 ± 0.41-fold increase in metallothionein 1X (MT1X) and metallothionein 2A (MT2A) gene expression. Zinc chelation during CA venom stimulation significantly increased cell viability, suggesting that the maintenance of zinc homeostasis during envenomation injury improves cell survival.

Bothrops (Fer-de-lance) snakebites in the French departments of the Americas (Martinique and Guyana): Clinical and experimental studies and treatment by immunotherapy.

Snakebite envenomation is a relevant medical hazard in French Guiana and Martinique, two French territories in the Americas. All snakebite envenomations in Martinique are inflicted by the endemic viperid species Bothrops lanceolatus, whereas Bothrops atrox is responsible for the majority of snakebites in French Guiana, although other venomous snake species also occur in this South American territory. This review summarizes some of the key aspects of the natural history of these species, as well as of their venom composition, the main clinical manifestations of envenomations, and their treatment by antivenoms. B. atrox venom induces the typical set of clinical manifestations characteristic of Bothrops sp. venoms, i.e., local tissue damage and systemic alterations associated with coagulopathies, hemorrhage, hemodynamic alterations, and acute kidney injury. In the case of B. lanceolatus venom, in addition to some typical features of bothropic envenomation, a unique and severe thrombotic effect occurs in some patients. The pathogenesis of this effect remains unknown but may be related to the action of venom components and inflammatory mediators on endothelial cells in the vasculature. A monospecific antivenom has been successfully used in Martinique to treat envenomations by B. lanceolatus. In the case of French Guiana, a polyvalent antivenom has been used for some years, but it is necessary to assess the preclinical and clinical efficacy against viperid venoms in this country of other antivenoms manufactured in the Americas.

Bothrops atrox mice experimental envenoming treatment using light-emitting diode (led) as an adjunct therapy to conventional serum therapy.

The use of anti-venom is one of the main control measures for snakebite envenoming when applied immediately after the snakebite. Systemic effects of the envenoming are usually reversed; however, neutralization of local effects is hardly achieved. The need for adjuvant therapies associated with serum therapy can improve the treatment for local effects of envenoming, with greater effectiveness in preventing or delaying the progression of damage, reducing the clinical signs and symptoms of victims of snakebites. The purpose of the study was to evaluate the photobiomodulation therapy using LED and/or dexamethasone associated with conventional serum therapy for the treatment of local damage caused by Bothrops atrox envenomation in a murine model. For this, experimental envenoming was carried out in the gastrocnemius muscle of male Swiss mice weighing 18 to 22g divided into 8 groups of animals, distributed in groups non-treat, treated with anti-bothropic serum, dexamethasone, and LED, or the associated treatments, by intramuscular inoculation of 50µg of venom or sterile PBS (control). After 30min, the proposed treatments were administered alone or in combination. After 3h, blood and muscle samples were collected for myotoxicity, cytotoxicity, histological analysis, and IL-1β assays. The evaluation of the treatment alone showed that serum therapy is not effective for the treatment of local damage and photobiomodulation demonstrated to be an effective therapy to reduce leukocyte infiltration, hemorrhage, and myotoxicity in experimental envenoming; dexamethasone proved to be a good resource for the treatment of the inflammatory process reducing the leukocyte infiltration. The association of serum therapy, LED, and dexamethasone was the best treatment to reduce the local effects caused by Bothrops atrox venom. All in all, the association of photobiomodulation therapy using LED with conventional serum therapy and the anti-inflammatory drug is the best treatment for reducing the undesirable local effects caused by snakebite accidents involving B. atrox species.

Two-Dimensional Blue Native/SDS Polyacrylamide Gel Electrophoresis for Analysis of Brazilian Bothrops Snake Venoms.

Viperidae snakes are the most important agents of snakebites in Brazil. The protein composition of snake venoms has been frequently analyzed by means of electrophoretic techniques, but the interaction of proteins in venoms has barely been addressed. An electrophoretic technique that has gained prominence to study this type of interaction is blue native polyacrylamide gel electrophoresis (BN-PAGE), which allows for the high-resolution separation of proteins in their native form. These protein complexes can be further discriminated by a second-dimension gel electrophoresis (SDS-PAGE) from lanes cut from BN-PAGE. Once there is no study on the use of bidimensional BN/SDS-PAGE with snake venoms, this study initially standardized the BN/SDS-PAGE technique in order to evaluate protein interactions in Bothrops atrox, Bothrops erythromelas, and Bothrops jararaca snake venoms. Results of BN/SDS-PAGE showed that native protein complexes were present, and that snake venom metalloproteinases and venom serine proteinases maintained their enzymatic activity after BN/SDS-PAGE. C-type lectin-like proteins were identified by Western blotting. Therefore, bidimensional BN/SDS-PAGE proved to be an easy, practical, and efficient method for separating functional venom proteins according to their assemblage in complexes, as well as to analyze their biological activities in further details.

CCL-2 and CXCL-8: Potential Prognostic Biomarkers of Acute Kidney Injury after a Bothrops atrox Snakebite.

In the Brazilian Amazon, the snake Bothrops atrox is the primary cause of snakebites. B. atrox (BaV) venom can cause systemic pathophysiological changes such as acute kidney injury (AKI), which leads to the production of chemokines and cytokines in response to the envenomation. These soluble immunological molecules act by modulating the inflammatory response; however, the mechanisms associated with the development of AKI are still poorly understood. Here, we characterize the profile of these soluble immunological molecules as possible predictive biomarkers of the development of AKI. The study involved 34 patients who had been victims of snakebites by Bothrops sp. These were categorized into two groups according to the development of AKI (AKI(-)/AKI(+)), using healthy donors as the control (HD). Peripheral blood samples were collected at three-time points: before antivenom administration (T0) and at 24 and 48 hours after antivenom (T1 and T2, respectively). The soluble immunological molecules (CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-γ, IL-4, and IL-17A) were quantified using cytometric bead array. Our results demonstrated an increase in CXCL-9, CXCL-10, IL-6, IL-2, IL-10, and IL-17A molecules in the groups of patients who suffered Bothrops snakebites (AKI(-) and AKI(+)) before antivenom administration, when compared to HD. In the AKI(+) group, levels of CXCL-8 and CCL-2 molecules were elevated on admission and progressively decreased during the clinical evolution of patients after antivenom administration. In addition, in the signature analysis, these were produced exclusively by the group AKI(+) at T0. Thus, these chemokines may be related to the initiation and extension of AKI after envenomation by Bothrops and present themselves as two potential biomarkers of AKI at T0.

Experimental Bothropsatrox Envenomation: Blood Plasma Proteome Effects after Local Tissue Damage and Perspectives on Thromboinflammation.

The clinical manifestations of Bothrops atrox envenoming involve local and systemic changes, among which edema requires substantial attention due to its ability to progress to compartmental syndromes and sometimes cause tissue loss and amputations. However, the impact of edema on the poisoned body’s system has not been explored. Thus, the present study aimed to explore the systemic pathological and inflammatory events that are altered by intraplantar injection of B. atrox venom in a mouse model through hematologic, lipidic, and shotgun proteomics analysis. Plasma samples collected showed a greater abundance of proteins related to complement, coagulation, lipid system, platelet and neutrophil degranulation, and pathways related to cell death and ischemic tolerance. Interestingly, some proteins, in particular, Prdx2 (peroxiredoxin 2), Hba (hemoglobin subunit alpha), and F9 (Factor IX), increased according to the amount of venom injected. Our findings support that B. atrox venom activates multiple blood systems that are involved in thromboinflammation, an observation that may have implications for the pathophysiological progression of envenomations. Furthermore, we report for the first time a potential role of Prdx2, Hba, and F9 as potential markers of the severity of edema/inflammation in mice caused by B. atrox.

Diversity of Phospholipases A2 from Bothrops atrox Snake Venom: Adaptive Advantages for Snakes Compromising Treatments for Snakebite Patients.

The evolution of snake venoms resulted in multigene toxin families that code for structurally similar isoforms eventually harboring distinct functions. PLA2s are dominant toxins in viper venoms, and little is known about the impact of their diversity on human envenomings and neutralization by antivenoms. Here, we show the isolation of three distinct PLA2s from B. atrox venom. FA1 is a Lys-49 homologue, and FA3 and FA4 are catalytic Asp-49 PLA2s. FA1 and FA3 are basic myotoxic proteins, while FA4 is an acid non-myotoxic PLA2. FA3 was the most potent toxin, inducing higher levels of edema, inflammatory nociception, indirect hemolysis, and anticoagulant activity on human, rat, and chicken plasmas. FA4 presented lower anticoagulant activity, and FA1 had only a slight effect on human and rat plasmas. PLA2s presented differential reactivities with antivenoms, with an emphasis on FA3, which was not recognized or neutralized by the antivenoms used in this study. Our findings reveal the functional and antigenic diversity among PLA2s from B. atrox venom, highlighting the importance of assessing venom variability for understanding human envenomations and treatment with antivenoms, particularly evident here as the antivenom fails to recognize FA3, the most active multifunctional toxin described.

A First Look at the Inhibitory Potential of Urospatha sagittifolia (Araceae) Ethanolic Extract for Bothrops atrox Snakebite Envenomation.

Bothrops atrox snakebites are a relevant problem in the Amazon basin. In this biodiverse region, the ethnomedicinal approach plays an important role as an alternative to antivenom therapy. Urospatha sagittifolia (Araceae) is a plant used for this purpose; however, its neutralizing properties have not been scientifically accessed. To fill this gap, we investigated the ability of U. sagittifolia to modulate the catalytic activity of Bothrops atrox venom, and their toxic consequences, such as local damage and lethality. The venom profile of B. atrox was assessed by chromatography and electrophoresis. Inhibition of the three main enzymatic and medically important toxins from the venom was evaluated using synthetic substrates and quantified by chromogenic activity assays. Additionally, the neutralization of lethality, hemorrhage and edema were investigated by in vivo assays. The possible interactions between venom proteins and plant molecules were visualized by polyacrylamide gel electrophoresis. Finally, the phytochemical constituents present in the ethanolic extract were determined by qualitative and quantitative analyses. The ethanolic extract reduced the activity of the three main enzymes of venom target, achieving ranges from 19% to 81% of inhibition. Our in vivo venom neuralizations assays showed a significant inhibition of edema (38.72%) and hemorrhage (42.90%). Additionally, lethality was remarkably counteracted. The highest extract ratio evaluated had a 75% survival rate. Our data support the biomedical value of U. sagittifolia as a source of natural enzyme inhibitors able to neutralize catalytically active B. atrox venom toxins and their toxic effects.

In vitro evaluation of canine whole blood with the addition of Crotalus atrox (Western Diamondback Rattlesnake) venom and antivenom using thromboelastography.

To compare the efficacy of 2 equine-origin antivenom products on correction of coagulation abnormalities noted on thromboelastography (TEG) caused by Crotalus atrox venom in vitro. Prospective in vitro controlled study. Veterinary teaching hospital. Six healthy dogs. Blood from each dog was used for 4 separate kaolin-activated TEG analyses: A negative control (blood-saline) and positive control (blood-Crotalus atrox venom) were used to assess the dog's normal coagulation and the effect of venom on TEG parameters. Thromboelastographic analyses were then run with blood, venom, and either Argentinian or North American antivenom. All TEG analyses from each dog were compared for efficacy. The mean R values between the North American antivenom and negative controls were not significantly different (P=0.681), but were significantly different (P=0.024) between the Argentinian antivenom and negative controls. The mean fibrinolysis values measured 30minutes after maximum amplitude achieved between the North American antivenom and negative controls were not significantly different (P=0.198), but were significantly different (P<0.001) between the Argentinian antivenom and negative controls. The mean K values between the Argentinian antivenom and negative controls were not significantly different (P=0.274), but were significantly different (P=0.043) between the North American antivenom and negative controls. The North American antivenom normalized time to clot formation and fibrinolysis, while the Argentinian antivenom normalized rate of clot formation. Further studies in naturally envenomated patients are necessary to determine if these in vitro results would translate into different clinical outcomes.

Crotalus atrox Induced Cellular Injury Triggers an Oxidative Stress Gene Response in HEK‐293T Cells

Wound and regeneration involves a series of complex processes that can induce oxidative stress by elevating intracellular reactive oxygen species (ROS) levels. In this study, we used RNA‐seq and qPCR to examine the molecular signature of Human Embryonic Kidney cells (HEK 293T) stimulated with Crotalus atrox venom. NGS data was assembled and annotated using BLASTx and UNIPROT. Results showed 243 genes were differentially expressed (106 upregulated, 137 downregulated) between Crotalus atrox stimulated and non‐stimulated cells (p&lt;0.05). HEK 293T stimulated with Crotalus atrox venom for 4 hours showed an increase in the expression of oxidative stress response genes (e.g., TOMM6, EGR (1,2,3), HSP70 (1A, 1B), UPK3BL (1,2)), and protein synthesis (ETV5, EMP1) (fc&gt;2.0). Significantly downregulated (log2(fc)&lt;‐1.20) genes were associated with protein coding (e.g., ABCG1, ABCA1, PPARA, HMGA2, TLCD5). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses identified 8 significant KEGG pathways, which included an amphetamine addiction pathway (p&lt;0.03). Genes identified in this pathway such as FosB proto‐oncogene (FosB) and activity regulated cytoskeleton protein (ARC) are connected to oxidative stress responses. Quantitative PCR (qPCR) was used to evaluate several genes identified from RNA‐seq data. Cells stimulated with Crotalus atrox venom for 4 hours induced an up‐regulation of HSPA1A (2.49±0.49), HSPA1B (2.04±0.12), and cytochrome P450 1A1 (CYP1A1) (3.24±0.33), matching NGS data trends. Pre‐incubation with the zinc chelator tris(2‐pyridylmethyl) amine (TPA) prior to venom stimulation induced a significant up‐regulation in HSPA1B (13.2±0.04). Extending Crotalus atrox venom stimulation to 8 hours increased the gene expression of metallothionein 1X (MT1X, 4.68±0.26) and peroxiredoxin‐4 (PRDX4, 3.34±0.11) compared to non‐stimulated cells. Interestingly, pre‐incubating cells with polyethylene glycol (PEG) catalase then stimulating cells with Crotalus atrox venom for 8 hours produced PRDX4 and MT1X gene expression values that were not significantly different from the non‐stimulated control. In contrast, glutathione peroxidase‐1 (GPx‐1) was significantly downregulated (0.27±0.16) after an 8 hour stimulation with Crotalus atrox venom, compared to non‐stimulated cells. Our data suggests Crotalus atrox induced cellular injury involves several gene families connected to oxidative stress responses.