RESUMO

Snakebite envenomings are considered a global health problem. The specific therapy for these envenomings consists of administering animal-derived antivenoms aiming to neutralize the venom toxins. Antivenoms have been used effectively to treat snakebites for more than a century; however, their administration may result in early and/or late adverse reactions. The present study presents the prevalence of early adverse reactions (EARs) towards Bothrops antivenom therapy in a health tertiary unit in the Brazilian Amazon and explores if specific plasma cytokines and chemokines from envenomed patients could be used as predictors of EARs. A cohort of patients bitten by Bothrops atrox was followed-up at the Fundação de Medicina Tropical Dr. Heitor Vieira Dourado (FMT-HVD), from 2014 to 2016. Patients were treated with the Brazilian Bothrops antivenom and CXCL-8, CCL-5, CXCL-9, CCL-2, CXCL-10, IL-6, TNF, IL-2, IL-10, IFN-y, IL-4, and IL-17A were evaluated in patients' plasma samples before and after antivenom administration. From the total of patients (n = 186), mostly were male (82.3%), inhabiting rural areas (87.1%), with an average age of 35 years. Most of the patients (83.8%) were admitted to the hospital within 6 h after the accident, 26 (14%) reported having suffered a previous snakebite, and 97 (52.1%) received between 7 and 9 antivenom vials. The frequency of antivenom-induced EARs was 11.8% (22), resulting mostly of mild reactions. Urticaria was the major EAR manifestation (46.4%). Interestingly, CXCL-8 and IL-2 showed significantly lower levels in patients who progressed to EARs, although IL-2 levels might not represent biological relevance due the small magnitude difference between groups. This study reveals that CXCL-8 and IL-2 could play a role in the onset of EARs in pit viper envenomings.

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RESUMO

We have investigated the mechanisms involved in the genesis of edema and nociception induced by Philodryas patagoniensis venom (PpV) injected into the footpad of mice. PpV induced dose-related edema and nociceptive effects. Pretreatment of mice with cyclooxygenase inhibitor (indomethacin), but not with cyclooxygenase 2 inhibitor (celecoxib) markedly inhibited both effects. Pretreatments with H1 receptor antagonist (promethazine) or with dual histamine-serotonin inhibitor (cyproheptadine) failed in inhibiting both effects. In groups pretreated with captopril (angiotensin-converting enzyme inhibitor) the edema was unaltered, but nociception was clearly increased, suggesting the participation of kinins in the pathophysiology of the nociception but not of the edema-forming effect of PpV. When PpV was treated with EDTA, the nociception was similar to the one induced by untreated venom, but edema was markedly reduced. We concluded that PpV-induced edema and nociception have cyclooxygenase eicosanoids as the main mediators and no participation of vasoactive amines. Kinins seem to participate in nociception but not in edema induced by PpV. The results also suggest that metalloproteinases are the main compounds responsible for the edema, but not for the nociception induced by this venom.

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RESUMO

Snakebites are a serious worldwide public health problem. In Brazil, about 90% of accidents are attributed to snakes from the Bothrops genus. The specific treatment consists of antivenom serum therapy, which has some limitations such as inability to neutralize local effects, difficult access in some regions, risk of immunological reactions, and high cost. Thus, the search for alternative therapies to treat snakebites is relevant. Jatropha mollissima (Euphorbiaceae) is a medicinal plant popularly used in folk medicine as an antiophidic remedy. Therefore, this study aims to evaluate the effect of the aqueous leaf extract from J. mollissima on local effects induced by Bothrops venoms. High Performance Liquid Chromatography with Diode Array Detection analysis and Mass Spectrometry analysis of aqueous leaf extract confirmed the presence of the flavonoids isoschaftoside, schaftoside, isoorientin, orientin, vitexin, and isovitexin. This extract, at 50-200 mg/kg doses administered by intraperitoneal route, showed significant inhibitory potential against local effects induced by Bothrops erythromelas and Bothrops jararaca snake venoms. Local skin hemorrhage, local edema, leukocyte migration, and myotoxicity were significantly inhibited by the extract. These results demonstrate that J. mollissima extract possesses inhibitory potential, especially against bothropic venoms, suggesting its potential as an adjuvant in treatment of snakebites.

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Esse estudo teve como objetivo determinar as alterações clínico-patológicas e laboratoriais em ovinos inoculados com a peçonha de Bothropoides jararaca e Bothrops jararacussu, no intuito de fornecer subsídios que possam facilitar o estabelecimento do diagnóstico e do diagnóstico diferencial dessa condição. Os venenos liofilizados foram diluídos em 1 ml de solução fisiológica e administrados a quatro ovinos por via subcutânea. Três ovinos foram a óbito e um que recebeu a dose de 0,5mg/kg (B. jararaca), recuperou-se. Os sinais clínicos tiveram início entre 7 minutos e 1 hora. O período de evolução variou de 7 horas 9 minutos a 21 horas 59 minutos. O quadro clínico, independentemente das doses, caracterizou-se por aumento de volume no local da inoculação, tempo de sangramento e de preenchimento capilar aumentados, taquicardia, dispnéia, mucosas hipocoradas e apatia. Os exames laboratoriais revelaram acentuada anemia normocítica normocrômica, trombocitopenia, acentuada redução de fibrinogênio e proteínas plasmáticas totais, hematócrito diminuído em dois animais, além de acentuado aumento de creatinaquinase e desidrogenase lática em todos os animais. À necropsia, os principais achados no local da inoculação e tecidos adjacentes eram extensas hemorragias no animal que recebeu o veneno de B. jararaca e edema e acentuado edema pulmonar agudo para os dois animais envenenados por B. jararacussu. Além de hemorragia e edema a principal alteração histopatológica verificada foi necrose das fibras musculares e de vasos, no local de inoculação e adjacências. A necrose tubular renal foi atribuída ao quadro de choque. Nos ovinos deste estudo, o aumento de volume observado no local de inoculação e adjacências era constituído predominantemente por sangue (B. jararaca) e por edema (B. jararacussu).

The purpose of this study was to establish the clinic-pathological and laboratory changes in sheep inoculated with Bothropoides jararaca and Bothrops jararacussu venom to provide subsidies for the differential diagnosis of snake bites. The liofilized venoms were diluted in 1 ml saline and administrated subcutaneously to four sheep. Three of the animals died, and the one that received 0.5mg/kg (B. jararaca venom) recovered. First symptoms were observed from 7 minutes to 1 hour after inoculation, and the clinical course varied from 7 hours and 9 minutes to 21 hours and 59 minutes. The symptoms, independent of the dosage, were swelling of the inoculation site, increased bleeding time and capillary filling, tachycardia, dyspnea, pale mucous membranes and diminished reaction to external stimuli. Laboratory tests revealed pronounced normocytic and normochromic anemia, trombocytopenia, slight reduction of fibrogen and total plasmatic protein, in two animals diminished hematocrit, besides pronounced increase of creatinaquinase and lactic dehydrogenase. At necropsy, the main findings at the inoculation site and adjacent tissues were extensive hemorrhages in the sheep inoculated with jararaca venom, and predominantly edema in the two animals inoculated with jararacussu venom. In two sheep which received jararacussu venom, acute pulmonary edema was observed. Hemorrhage and edema as the main histopathological changes, besides necrosis of muscle fibers and vessels at the inoculation site and adjacent tissue was observed. The renal tubular necrosis was attributed to shock. The volume increase at the inoculation site and surroundings was mainly due to hemorrhage (B. jararaca) or edema (B. jararacussu).

Assuntos

RESUMO

Esse estudo teve como objetivo determinar as alterações clínico-patológicas e laboratoriais em ovinos inoculados com a peçonha de Bothropoides jararaca e Bothrops jararacussu, no intuito de fornecer subsídios que possam facilitar o estabelecimento do diagnóstico e do diagnóstico diferencial dessa condição. Os venenos liofilizados foram diluídos em 1 ml de solução fisiológica e administrados a quatro ovinos por via subcutânea. Três ovinos foram a óbito e um que recebeu a dose de 0,5mg/kg (B. jararaca), recuperou-se. Os sinais clínicos tiveram início entre 7 minutos e 1 hora. O período de evolução variou de 7 horas 9 minutos a 21 horas 59 minutos. O quadro clínico, independentemente das doses, caracterizou-se por aumento de volume no local da inoculação, tempo de sangramento e de preenchimento capilar aumentados, taquicardia, dispnéia, mucosas hipocoradas e apatia. Os exames laboratoriais revelaram acentuada anemia normocítica normocrômica, trombocitopenia, acentuada redução de fibrinogênio e proteínas plasmáticas totais, hematócrito diminuído em dois animais, além de acentuado aumento de creatinaquinase e desidrogenase lática em todos os animais. À necropsia, os principais achados no local da inoculação e tecidos adjacentes eram extensas hemorragias no animal que recebeu o veneno de B. jararaca e edema e acentuado edema pulmonar agudo para os dois animais envenenados por B. jararacussu. Além de hemorragia e edema a principal alteração histopatológica verificada foi necrose das fibras musculares e de vasos, no local de inoculação e adjacências. A necrose tubular renal foi atribuída ao quadro de choque. Nos ovinos deste estudo, o aumento de volume observado no local de inoculação e adjacências era constituído predominantemente por sangue (B. jararaca) e por edema (B. jararacussu).(AU)

The purpose of this study was to establish the clinic-pathological and laboratory changes in sheep inoculated with Bothropoides jararaca and Bothrops jararacussu venom to provide subsidies for the differential diagnosis of snake bites. The liofilized venoms were diluted in 1 ml saline and administrated subcutaneously to four sheep. Three of the animals died, and the one that received 0.5mg/kg (B. jararaca venom) recovered. First symptoms were observed from 7 minutes to 1 hour after inoculation, and the clinical course varied from 7 hours and 9 minutes to 21 hours and 59 minutes. The symptoms, independent of the dosage, were swelling of the inoculation site, increased bleeding time and capillary filling, tachycardia, dyspnea, pale mucous membranes and diminished reaction to external stimuli. Laboratory tests revealed pronounced normocytic and normochromic anemia, trombocytopenia, slight reduction of fibrogen and total plasmatic protein, in two animals diminished hematocrit, besides pronounced increase of creatinaquinase and lactic dehydrogenase. At necropsy, the main findings at the inoculation site and adjacent tissues were extensive hemorrhages in the sheep inoculated with jararaca venom, and predominantly edema in the two animals inoculated with jararacussu venom. In two sheep which received jararacussu venom, acute pulmonary edema was observed. Hemorrhage and edema as the main histopathological changes, besides necrosis of muscle fibers and vessels at the inoculation site and adjacent tissue was observed. The renal tubular necrosis was attributed to shock. The volume increase at the inoculation site and surroundings was mainly due to hemorrhage (B. jararaca) or edema (B. jararacussu).(AU)

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The effects of Crotalus durissus terrificus venom (Cdt) were analyzed with respect to the susceptibility and the inflammatory mediators in an experimental model of severe envenomation. BALB/c female mice injected intraperitoneally presented sensibility to Cdt, with changes in specific signs, blood biochemical and inflammatory mediators. The venom induced reduction of glucose and urea levels and an increment of creatinine levels in serum from mice. Significant differences were observed in the time-course of mediator levels in sera from mice injected with Cdt. The maximum levels of IL-6, NO, IL-5, TNF, IL-4 and IL-10 were observed 15 min, 30 min, 1, 2 and 4 hours post-injection, respectively. No difference was observed for levels of IFN-gamma. Taken together, these data indicate that the envenomation by Cdt is regulated both pro- and anti-inflammatory cytokine responses at time-dependent manner. In serum from mice injected with Cdt at the two first hours revealed of pro-inflammatory dominance. However, with an increment of time an increase of anti-inflammatory cytokines was observed and the balance toward to anti-inflammatory dominance. In conclusion, the observation that Cdt affects the production of pro- and anti-inflammatory cytokines provides further evidence for the role played by Cdt in modulating pro/anti-inflammatory cytokine balance.

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The immunochemical reactivity and neutralizing capacity of polyvalent Vipera antivenom (Vipera ammodytes, Vipera aspis, Vipera berus, Vipera lebetina, and Vipera xanthina) were tested on the enzymatic and biological activities of Crotalus durissus terrificus and the following Bothrops venoms from Argentina (Bothrops alternatus, Bothrops ammodytoides, Bothrops neuwiedii, Bothrops jararaca, Bothrops jararacussu, and Bothrops moojeni). The Vipera antivenom reacted weakly when tested by double immunoprecipitation (DIP) and reacted with all the venoms when tested by ELISA. Several components in all the venoms studied were recognized in Western blots. Vipera antivenom deactivated to different degrees in vitro procoagulant, (indirect) hemolytic, and proteolytic activities in all the venoms studied. Preincubation of Bothrops alternatus venom with Vipera antivenom neutralized a lethal potency of 4.5 LD50 in mice with an ED50 of 1.25 ñ 0.25 µl per µg of venom, and with 1.0 µl/µg inhibited 54 per cent of the hemorragic activity and 48 per cent of necrotic activity. Vipera antivenom (2.0 µl per µg toxin) inhibited the phospholipase A2 activity of purified crotoxin and decreased its lethal potency by 60 per cent, while the neutralizing capacity on the lethal potency of crude Crotalus durissus terrificus venom was poor even at a level of 5.0 µl/µg of venom.

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