Variability in antivenom neutralization of Mexican viperid snake venoms.

BACKGROUND: Each year, 3,800 cases of snakebite envenomation are reported in Mexico, resulting in 35 fatalities. The only scientifically validated treatment for snakebites in Mexico is the use of antivenoms. Currently, two antivenoms are available in the market, with one in the developmental phase. These antivenoms, produced in horses, consist of F(ab')2 fragments generated using venoms from various species as immunogens. While previous studies primarily focused on neutralizing the venom of the Crotalus species, our study aims to assess the neutralization capacity of different antivenom batches against pit vipers from various genera in Mexico. METHODOLOGY: We conducted various biological and biochemical tests to characterize the venoms. Additionally, we performed neutralization tests using all three antivenoms to evaluate their effectiveness against lethal activity and their ability to neutralize proteolytic and fibrinogenolytic activities. RESULTS: Our results reveal significant differences in protein content and neutralizing capacity among different antivenoms and even between different batches of the same product. Notably, the venom of Crotalus atrox is poorly neutralized by all evaluated batches despite being the primary cause of envenomation in the country's northern region. Furthermore, even at the highest tested concentrations, no antivenom could neutralize the lethality of Metlapilcoatlus nummifer and Porthidium yucatanicum venoms. These findings highlight crucial areas for improving existing antivenoms and developing new products. CONCLUSION: Our research reveals variations in protein content and neutralizing potency among antivenoms, emphasizing the need for consistency in venom characteristics as immunogens. While Birmex neutralizes more LD50 per vial, Antivipmyn excels in specific neutralization. The inability of antivenoms to neutralize certain venoms, especially M. nummifer and P. yucatanicum, highlights crucial improvement opportunities, given the medical significance of these species.

A longitudinal study of the blood and urine metabolome of Vipera berus envenomated dogs.

Envenomation of dogs by the common European adder (Vipera berus) is associated with high morbidity. The cytotoxic venom of Vipera berus contains enzymes with the potential to cause acute kidney injury, among other insults, however robust biomarkers for such effects are lacking. A prospective observational follow-up study of naturally envenomated dogs and controls was conducted to fill knowledge gaps regarding canine Vipera berus envenomation, attempt to identify novel biomarkers of envenomation and related kidney injury, and elucidate potential long-term effects. Blood and urine samples were analyzed with a global metabolomics approach using liquid chromatography-mass spectrometry, uncovering numerous features significantly different between cases and controls. After data processing and feature annotation, eight features in blood and 24 features in urine were investigated in order to elucidate their biological relevance. Several of these are associated with AKI, while some may also originate from disturbed fatty acid ß-oxidation and soft tissue damage. A metabolite found in both blood and a venom reference sample may represent identification of a venom component in case dogs. Our findings suggest that envenomated dogs treated according to current best practice are unlikely to suffer permanent injury.

Peripheral Nerve Block to Treat Pain Caused by Daboia palaestinae Envenomation.

Snakebite pain can be challenging to control. We describe our experience managing intolerable pain after conventional treatment failed. A 35-year-old man, presented after a viper snakebite, suffering from intolerable pain in the affected extremity. He had no significant past medical history. All attempts to control the pain conventionally were unsuccessful. Treatment with a supraclavicular nerve block resulted in immediate relief. After the block receded, only a dull pain remained, which later disappeared without recurrence. This experience illustrates the need for personalized pain treatment to avoid subsequent complications.

Reproductive cycles of two island pitvipers species (Serpentes, Viperidae) determined by ultrasonography and radiography.

We used ultrasonography and radiography to assess the sexual organs and characterize the reproductive cycle of captive golden lancehead (Bothrops insularis) and Alcatrazes lancehead (B. alcatraz), two endangered island snake species in Brazil. We assessed 46- individuals of golden lancehead and 12 of Alcatrazes lancehead kept in captivity between 2014 and 2020. Follicular development was similar between species, but follicles in Alcatrazes lancehead were smaller than in the golden lanceheads. Female golden lanceheads produced 24 live young, seven stillborn and 73 undeveloped eggs. Parturition of live young occurred between midsummer (February) and early autumn and gestation averaged 8 months. Female Alcatrazes lanceheads produced four live young in midsummer, and one undeveloped egg in early autumn. Males and females of both species have seasonal and biennial reproductive cycles. Sperm storage in both sexes is essential to coordinate male and female cycles. The data obtained with golden lancehead and Alcatrazes lancehead in captivity, demonstrate a degree of conservatism, following data from other Bothrops.

Phylogenomics of Psammodynastes and Buhoma (Elapoidea: Serpentes), with the description of a new Asian snake family.

Asian mock vipers of the genus Psammodynastes and African forest snakes of the genus Buhoma are two genera belonging to the snake superfamily Elapoidea. The phylogenetic placements of Psammodynastes and Buhoma within Elapoidea has been extremely unstable which has resulted in their uncertain and debated taxonomy. We used ultraconserved elements and traditional nuclear and mitochondrial markers to infer the phylogenetic relationships of these two genera with other elapoids. Psammodynastes, for which a reference genome has been sequenced, were found, with strong branch support, to be a relatively early diverging split within Elapoidea that is sister to a clade consisting of Elapidae, Micrelapidae and Lamprophiidae. Hence, we allocate Psammodynastes to its own family, Psammodynastidae new family. However, the phylogenetic position of Buhoma could not be resolved with a high degree of confidence. Attempts to identify the possible sources of conflict in the rapid radiation of elapoid snakes suggest that both hybridisation/introgression during the rapid diversification, including possible ghost introgression, as well as incomplete lineage sorting likely have had a confounding role. The usual practice of combining mitochondrial loci with nuclear genomic data appears to mislead phylogeny reconstructions in rapid radiation scenarios, especially in the absence of genome scale data.

Pit Viper Envenomation in Two Pregnant Bitches.

Snake envenomation is relatively common in small animals, particularly in endemic areas. Effects and outcomes of envenomation during pregnancy are poorly described in humans and more so in veterinary patients. Two young pregnant female dogs presented to a university teaching hospital with a history of acute soft tissue swelling and bleeding. History, physical examination findings, and diagnostics were consistent with envenomation by crotalid snakes. Medical management of one of the dogs included administration of antivenin. Both dogs survived envenomation with minimal complications and went on to whelp without complications, and all fetuses survived. This is the first description of the management of pit viper envenomation in pregnant dogs.

Paranannizziopsis spp. Infection in Wild Vipers, Europe.

We describe the detection of Paranannizziopsis sp. fungus in a wild population of vipers in Europe. Fungal infections were severe, and 1 animal likely died from infection. Surveillance efforts are needed to better understand the threat of this pathogen to snake conservation.

The use of rotational thromboelastometry to guide management following Bitis nasicornis envenoming.

A man in his thirties presented following Bitis nasicornis envenoming. His coagulation was assessed using rotational thromboelastometry (ROTEM). It identified a subtle abnormality, not detected using standard laboratory assessments of coagulation, and influenced ongoing management. The abnormality resolved following treatment with antivenom. There are few documented cases of using ROTEM to assess patients following haemotoxic envenoming. This case highlights some of the potential benefits and limitations of doing so.

Distinct regulatory networks control toxin gene expression in elapid and viperid snakes.

BACKGROUND: Venom systems are ideal models to study genetic regulatory mechanisms that underpin evolutionary novelty. Snake venom glands are thought to share a common origin, but there are major distinctions between venom toxins from the medically significant snake families Elapidae and Viperidae, and toxin gene regulatory investigations in elapid snakes have been limited. Here, we used high-throughput RNA-sequencing to profile gene expression and microRNAs between active (milked) and resting (unmilked) venom glands in an elapid (Eastern Brown Snake, Pseudonaja textilis), in addition to comparative genomics, to identify cis- and trans-acting regulation of venom production in an elapid in comparison to viperids (Crotalus viridis and C. tigris). RESULTS: Although there is conservation in high-level mechanistic pathways regulating venom production (unfolded protein response, Notch signaling and cholesterol homeostasis), there are differences in the regulation of histone methylation enzymes, transcription factors, and microRNAs in venom glands from these two snake families. Histone methyltransferases and transcription factor (TF) specificity protein 1 (Sp1) were highly upregulated in the milked elapid venom gland in comparison to the viperids, whereas nuclear factor I (NFI) TFs were upregulated after viperid venom milking. Sp1 and NFI cis-regulatory elements were common to toxin gene promoter regions, but many unique elements were also present between elapid and viperid toxins. The presence of Sp1 binding sites across multiple elapid toxin gene promoter regions that have been experimentally determined to regulate expression, in addition to upregulation of Sp1 after venom milking, suggests this transcription factor is involved in elapid toxin expression. microRNA profiles were distinctive between milked and unmilked venom glands for both snake families, and microRNAs were predicted to target a diversity of toxin transcripts in the elapid P. textilis venom gland, but only snake venom metalloproteinase transcripts in the viperid C. viridis venom gland. These results suggest differences in toxin gene posttranscriptional regulation between the elapid P. textilis and viperid C. viridis. CONCLUSIONS: Our comparative transcriptomic and genomic analyses between toxin genes and isoforms in elapid and viperid snakes suggests independent toxin regulation between these two snake families, demonstrating multiple different regulatory mechanisms underpin a venomous phenotype.

Isolation and characterization of polymorphic microsatellite loci for the three Iberian vipers, Vipera aspis, V. Latastei and V. seoanei by Illumina MiSeq sequencing.

BACKGROUND: European vipers (genus Vipera) are a well-studied taxonomic group, but the low resolution of nuclear sanger-sequenced regions has precluded thorough studies at systematic, ecological, evolutionary and conservation levels. In this study, we developed novel microsatellite markers for the three Iberian vipers, Vipera aspis, V. latastei and V. seoanei, and assessed their polymorphism in north-central Iberian populations. METHODS AND RESULTS: Genomic libraries were developed for each species using an Illumina Miseq sequencing approach. From the 70 primer pairs initially tested, 48 amplified reliably and were polymorphic within species. Cross-species transferability was achieved for 31 microsatellites loci in the three target species and four additional loci that were transferable to one species only. The 48 loci amplified in average seven alleles, and detected average expected and observed heterozygosities of 0.7 and 0.55, in the three genotyped populations/species (26 V. aspis, 20 V. latastei and 10 V. seoanei). CONCLUSIONS: Our study provides a selection of 48 polymorphic microsatellite markers that will contribute significantly to current knowledge on genetic diversity, gene flow, population structure, demographic dynamics, systematics, reproduction and heritability in these species, and potentially in other congeneric taxa.

Serpentirhabdias mexicanus n. sp. (Nematoda: Rhabdiasidae), a parasitic lungworm of the nauyaca viper Bothrops asper (Serpentes: Viperidae) in the Mexican Neotropics.

Serpentirhabdias mexicanus n. sp. (Nematoda: Rhabdiasidae) is described from the lung of the nauyaca viper Bothrops asper in Puebla State, central Mexico. This new species is the fifth of the genus described having onchia. Among the species included in this group, the new species is morphologically closest to S. viperidicus and S. atroxi. However, it differs from both species mainly by having only one excretory gland (compared to two present in S. viperidicus and S. atroxi). In addition, S. mexicanus n. sp. can be separated of S. viperidicus by tail length, shape of vulval lips, geographic distribution and host species and from S. atroxi by body length, number of papillae in the cephalic region, as well as the host species and geographic distribution. In the present study, we propose the new species based on morphological, host spectrum and genetic evidence. Phylogenetic analysis indicated Serpentirhabdias as a monophyletic group, with two subgroups that are congruent with the presence/absence of onchia in the esophagostome, host association and other relevant morphological characters.

Changes in attachment and metabolic activity of rat neonatal cardiomyocytes and nonmyocytes caused by Macrovipera lebetina obtusa venom.

The Caucasian viper Macrovipera lebetina obtusa (MLO) is one of the most prevalent and venomous snakes in the Caucasus and the surrounding regions, yet the effects of MLO venom on cardiac function remain largely unknown. We examined the influence of MLO venom (crude and with inhibited metalloproteinases and phospholipase A2) on attachment and metabolic activity of rat neonatal cardiomyocytes (CM) and nonmyocytes (nCM), assessed at 1 and 24 h. After exposing both CM and nCM to varying concentrations of MLO venom, we observed immediate cytotoxic effects at a concentration of 100 µg/ml, causing detachment from the culture substrate. At lower MLO venom concentrations both cell types detached in a dose-dependent manner. Inhibition of MLO venom metalloproteinases significantly improved CM and nCM attachment after 1-hour exposure. At 24-hour exposure to metalloproteinases inhibited venom statistically significant enhancement was observed only in nCM attachment. However, metabolic activity of CM and nCM did not decrease upon exposure to the lower dose of the venom. Moreover, we demonstrated that metalloproteinases and phospholipases A2 are not the components of the MLO venom that change metabolic activity of both CM and nCM. These results provide a valuable platform to study the impact of MLO venom on prey cardiac function. They also call for further exploration of individual venom components for pharmaceutical purposes.

An agonist of CXCR4 induces a rapid recovery from the neurotoxic effects of Vipera ammodytes and Vipera aspis venoms.

People bitten by Alpine vipers are usually treated with antivenom antisera to prevent the noxious consequences caused by the injected venom. However, this treatment suffers from a number of drawbacks and additional therapies are necessary. The venoms of Vipera ammodytes and of Vipera aspis are neurotoxic and cause muscle paralysis by inducing neurodegeneration of motor axon terminals because they contain a presynaptic acting sPLA2 neurotoxin. We have recently found that any type of damage to motor axons is followed by the expression and activation of the intercellular signaling axis consisting of the CXCR4 receptor present on the membrane of the axon stump and of its ligand, the chemokine CXCL12 released by activated terminal Schwann cells. We show here that also V. ammodytes and V. aspis venoms cause the expression of the CXCL12-CXCR4 axis. We also show that a small molecule agonist of CXCR4, dubbed NUCC-390, induces a rapid regeneration of the motor axon terminal with functional recovery of the neuromuscular junction. These findings qualify NUCC-390 as a promising novel therapeutics capable of improving the recovery from the paralysis caused by the snakebite of the two neurotoxic Alpine vipers.

Hidden in the sand: Phylogenomics unravel an unexpected evolutionary history for the desert-adapted vipers of the genus Cerastes.

The desert vipers of the genus Cerastes are a small clade of medically important venomous snakes within the family Viperidae. According to published morphological and molecular studies, the group is comprised by four species: two morphologically similar and phylogenetically sister taxa, the African horned viper (Cerastes cerastes) and the Arabian horned viper (Cerastes gasperettii); a more distantly related species, the Saharan sand viper (Cerastes vipera), and the enigmatic Böhme's sand viper (Cerastes boehmei), only known from a single specimen in captivity allegedly captured in Central Tunisia. In this study, we sequenced one mitochondrial marker (COI) as well as genome-wide data (ddRAD sequencing) from 28 and 41 samples, respectively, covering the entire distribution range of the genus to explore the population genomics, phylogenomic relationships and introgression patterns within the genus Cerastes. Additionally, and to provide insights into the mode of diversification of the group, we carried out niche overlap analyses considering climatic and habitat variables. Both nuclear phylogenomic reconstructions and population structure analyses have unveiled an unexpected evolutionary history for the genus Cerastes, which sharply contradicts the morphological similarities and previously published mitochondrial approaches. Cerastes cerastes and C. vipera are recovered as sister taxa whilst C. gasperettii is a sister taxon to the clade formed by these two species. We found a relatively high niche overlap (OI > 0.7) in both climatic and habitat variables between C. cerastes and C. vipera, contradicting a potential scenario of sympatric speciation. These results are in line with the introgression found between the northwestern African populations of C. cerastes and C. vipera. Finally, our genomic data confirms the existence of a lineage of C. cerastes in Arabia. All these results highlight the importance of genome-wide data over few genetic markers to study the evolutionary history of species.

Structural, biochemical and immunochemical characterization of an acidic phospholipase A2 from Lachesis acrochorda (Viperidae: Crotalinae) venom.

Viperids of the genus Lachesis, also known as bushmasters, are capable of injecting great amounts of venom that cause severe envenomation incidents. Since phospholipases type A2 are mainly involved in edema and myonecrosis within the snakebite sites, in this work, the isolation, amino acid sequence and biochemical characterization of the first phospholipase type A2 from the venom of Lachesis acrochorda, named Lacro_PLA2, is described. Lacro_PLA2 is an acidic aspartic 49 calcium-dependent phospholipase A2 with 93% similarity to the L. stenophrys phospholipase. Lacro_PLA2 has a molecular mass of 13,969.7 Da and an experimental isoelectric point around 5.3. A combination of N-terminal Edman degradation and MS/MS spectrometry analyses revealed that Lacro_PLA2 contains 122 residues including 14 cysteines that form 7 disulfide bridges. A predicted 3D model shows a high resemblance to other viperid phospholipases. Nevertheless, immunochemical and phospholipase neutralization tests revealed a notorious level of immunorecognition of the isolated protein by two polyclonal antibodies from viperids from different genus, which suggest that Lacro_PLA2 resembles more to bothropic phospholipases. Lacro_PLA2 also showed significantly high edema activity when was injected into mice; so, it could be an alternative antigen in the development of antibodies against toxins of this group of viperids, seeking to improve commercial polyclonal antivenoms.

Snake and arthropod venoms: Search for inflammatory activity in human cells involved in joint diseases.

Most anti-inflammatory drugs currently adopted to treat chronic inflammatory joint diseases can alleviate symptoms but they do not lead to remission. Therefore, new and more efficient drugs are needed to block the course of joint inflammatory diseases. Animal venoms, rich in bioactive compounds, can contribute as valuable tools in this field of research. In this study, we first demonstrate the direct action of venoms on cells that constitute the articular joints. We established a platform consisting of cell-based assays to evaluate the release of cytokines (IL-6, IL-8, TNFα, IL-1ß, and IL-10) by human chondrocytes, synoviocytes and THP1 macrophages, as well as the release of neuropeptides (substance-P and ß-endorphin) by differentiated sensory neuron-like cells, 24 h after stimulation of cells with 21 animal venoms from snake and arthropod species, sourced from different taxonomic families and geographic origins. Results demonstrated that at non-cytotoxic concentrations, the venoms activate at varying degrees the secretion of inflammatory mediators involved in the pathology of articular diseases, such as IL-6, IL-8, and TNF-α by chondrocytes, synoviocytes, and macrophages and of substance P by neuron-like cells. Venoms of the Viperidae snake family were more inflammatory than those of the Elapidae family, while venoms of Arthropods were less inflammatory than snake venoms. Notably, some venoms also induced the release of the anti-inflammatory IL-10 by macrophages. However, the scorpion Buthus occitanus venom induced the release of IL-10 without increasing the release of inflammatory cytokines by macrophages. Since the cell types used in the experiments are crucial elements in joint inflammatory processes, the results of this work may guide future research on the activation of receptors and inflammatory signaling pathways by selected venoms in these particular cells, aiming at discovering new targets for therapeutic intervention.

The Brazilian Atlantic Bushmaster Lachesis (Linnaeus, 1766) Mitogenome With Insights On Snake Evolution And Divergence (Serpentes: Viperidae: Crotalinae).

This study presents the first complete mitogenome of the Brazilian Atlantic bushmaster Lachesis with insights into snake evolution. The total length was 17,177 bp, consisting of 13 PCGs, 22 tRNAs, two rRNAs and a duplicate control region (CRs). Almost all genes were encoded by the heavy-strand, except for the ND6 gene and eight tRNAs (tRNA-Gln, Ala, Asn, Cys, Tyr, Ser[TGA anticodon], Glu, Pro). Only ATG, ATA, and ATC were starting codons for protein-coding sequences. Stop codons mainly were TAA, AGA, AGG, and TAG; whereas ND1, ND3, and CYTB terminated with incomplete stop codons. Phylogeny retrieved Lachesis within the Crotalinae as the sister group of Agkistrodon; and the Lachesis+Agkistrodon clade as the sister group of (Sistrurus+Crotalus)+Bothrops. The tree supports Crotalinae, Viperinae, and Azemiopinae in the Viperidae family, being sister taxa of Colubridae+(Elapidae+Psammophiidae). The mean genetic distance across 15 snake families and 57 nucleotide sequences was 0.37. The overall mean value of genetic distance across the Crotalinae was 0.23, with Lachesis muta exhibiting the shortest distance of 0.2 with Agkistrodon piscivorus, Protobothrops dabieshanensis and P. flavoviridis and the greatest 0.25 with Gloydius blomhoffii, Trimeresurus albolabris, S. miliarius, and Deinagkistrodon acutus. The complete Atlantic L. muta mitogenome presented herein is only the third annotated mitogenome from more than 430 described Brazilian snake species.

Local niches explain coexistence in environmentally-distinct contact zones between Western Mediterranean vipers.

Species' ecological niches are frequently analysed to gain insights into how anthropogenic changes affect biodiversity. Coping with these changes often involves shifts in niche expression, which can disrupt local biotic interactions. Secondary contact zones, where competition and ecological segregation commonly occur, are ideal for studying the ecological factors influencing species' niches. In this study, we investigated the effect of climate and landscape factors on the ecological niches of two viper species, Vipera aspis and Vipera latastei, across three contact zones in northern Iberia, characterized by varying levels of landscape alteration. Using niche overlap tests, ecological niche models and spatial analyses we observed local variation in the expression of the species' niches across the three contact zones, resulting from the different abiotic and biotic conditions of each area. Rather than spatial niche segregation, we observed high niche overlap, suggesting niche convergence. A pattern of asymmetrical niche variation was identified in all contact zones, driven by species' climatic tolerances and the environmental conditions of each area. V. aspis generally exhibited a wider niche, except in the southernmost zone where the pure Mediterranean climate favored V. latastei. Human-induced landscape changes intensified niche asymmetry, by favoring the most generalist V. aspis over the specialist V. latastei, increasing habitat overlap, and likely competition. This study presents a comprehensive analysis of niche expression at range margins, anticipating a heightened impact of landscape changes in V. latastei. The methodological framework implemented here, and our findings, hold significant relevance for biodiversity management and conservation in human-impacted areas.

In vitro anti-inflammatory activity of Plantago major L. and Piper aduncum L. on phospholipase A2 from the venom of snake Lachesis muta muta. / Actividad antiinflamatoria in vitro de Plantago major L. y Piper aduncum L. sobre la fosfolipasa A2 del veneno de la serpiente Lachesis muta muta.

OBJECTIVE.: To evaluate the in vitro inhibitory activity of Plantago major "llantén" and Piper aduncum "matico" extracts on phospholipase A2 (PLA2) from the venom of the snake Lachesis muta muta. MATERIALS AND METHODS.: We carried out an explanatory study with experimental design. Leaves of P. major and P. aduncum were collected in the province of Huarochirí in Lima, Peru. Then, we prepared alcoholic extracts diluted in distilled water and conducted phytochemical assays, quantification of phenols and flavonoids, thin layer chromatography (TLC) on cellulose and enzymatic activity with PLA2. The ability to inhibit PLA2 with the extracts under study and their fractions was analyzed. The Kruskal Wallis test and Bonferroni multiple comparisons were used during statistical analysis. RESULTS.: Phenols, flavonoids and tannins were qualitatively identified in both P. major and P. aduncum; in addition, P. aduncum presented saponins. The inhibition of PLA2 activity of the venom by the total extract of P. major was 45.3%, and its fractions showed the following inhibition values: 31.1% for LLF-1, 66.3% for LLF-2 and 65.5% for LLF-3. The inhibition values for the total extract of P. aduncum were 86.9%, and its fractions showed the following inhibition rates: 34.3% for MF-1, 67.1% for MF-2 and 54.9% for MF-3. Statistical analysis showed significant differences in the inhibition of PLA2 (p=0.009) by the extracts. CONCLUSION.: The tests demonstrated an association between the anti-inflammatory effect of the extracts and PLA2 inhibition.

OBJETIVO.: Evaluar la actividad inhibitoria in vitro de los extractos de Plantago major «llantén¼ y Piper aduncum «matico¼ sobre Fosfolipasa A2 (PLA2) del veneno de la serpiente Lachesis muta muta. MATERIALES Y MÉTODOS.: Esta investigación fue de tipo explicativa con diseño experimental. Se recolectaron hojas de P. major y P. aduncum en la provincia de Huarochirí en Lima, Perú. Se prepararon extractos alcohólicos diluidos en agua destilada y se realizaron los ensayos fitoquímicos, la cuantificación de fenoles y flavonoides, la cromatografía de capa fina (CCF) en celulosa y la actividad enzimática con PLA2. Se analizó la capacidad de inhibir la PLA2 con los extractos en estudio y sus fracciones. Para el análisis estadístico se utilizó la prueba de Kruskal Wallis y comparaciones múltiples de Bonferroni. RESULTADOS.: Tanto en P. major como en P. aduncum se identificó cualitativamente la presencia de fenoles, flavonoides y taninos; además, P. aduncum presentó saponinas. La inhibición de la actividad de la PLA2 del veneno por el extracto total de P. major fue del 45,3%, y sus fracciones mostraron valores de inhibición: LLF-1 con 31,1%, LLF-2 con 66,3% y LLF-3 con 65,5%. En P. aduncum, los valores de inhibición para el extracto total fueron de 86,9%, y sus fracciones presentaron inhibiciones: MF-1 con 34,3%, MF-2 con 67,1% y MF-3 con 54,9%. El análisis estadístico demostró diferencias significativas en la inhibición de la PLA2 (p=0,009) por los extractos. CONCLUSIÓN.: Los ensayos realizados demostraron una asociación entre el efecto antiinflamatorio de los extractos y la inhibición de la PLA2.

Proteomic characteristics of six snake venoms from the Viperidae and Elapidae families in China and their relation to local tissue necrosis.

Patients envenomed by snakes from the Viperidae and Elapidae families in China often have varying degrees of local tissue necrosis. Due to the relative clinical characteristics of local tissue necrosis and ulceration following envenoming, this study has analyzed the proteome of six snake venoms from the Viperidae and Elapidae family, and the toxin profiles of each snake were compared and correlated with the clinical manifestations that follow cytotoxic envenoming. Deinagkistrodon acutus and Naja atra envenomation induce severe ulceration, which is absent in Bungarus multicinctus envenomation and mild in the other three vipers. It is interesting to note that the proportion of c-type lectins (CTL) (20.63%) in Deinagkistrodon acutus venom was relatively high, which differs from the venom of other vipers. In addition, three-fingered toxin (3FTx) (2.15%) is present in the venom of Deinagkistrodon acutus, but has not been detected in the remaining three vipers. Snake venom metalloprotease (SVMP) (34.4%-44.7%), phospholipase A2 (PLA2) (9.81%-40.83%), and snake venom serine protease (SVSP) (9.44%-16.2%) represent the most abundant families of toxin in Viperidae venom. The Elapidae venom proteome was mainly composed of neurotoxins and cytotoxins, including 3FTx (39.28%-60.08%) and PLA2 (8.24%-58.95%) toxins, however, the proportion of CRISPS (26.36%) in Naja atra venom was relatively higher compared to Bungarus multicinctus venom. Significant differences in SVMP, SVSP, and 3FTx expression levels exist between the Viperidae and the Elapidae family. The main toxins responsible for the development of tissue necrosis and ulcerations following Viperidae envenoming are hematotoxins (SVSMP, SVSP) and myotoxins (PLA2). Deinagkistrodon acutus venom contains high levels of CTL and traces of 3FTx, leading to more severe local necrosis. However, Naja atra venom can also cause severe local necrosis through the effects of myotoxin (3FTx, CRISP, PLA2). Bungarus multicinctus venom does not contain myotoxins, resulting in pure systemic neurological manifestations no obvious necrosis of local tissue in patients.