Effect of perimuscular injection of Bothrops jararacussu venom on plasma creatine kinase levels in mice: influence of dose and volume

Doxycycline treatment reestablishes renal function of Wistar rats in experimental envenomation with Bothrops jararacussu venom

Acute kidney injury is one of the main complications of ophidian accidents and the leading cause of death in patients who survive the initial damage effects of venom. The hypothesis proposed in this investigation is that the pharmacological repositioning of doxycycline (doxy) attenuates renal injury provoked by Bothrops jararacussu (Bj) venom. Male Wistar rats were subjected or not (control) to experimental envenomation with Bj venom (3.5 mg/kg, im). Doxy (3 mg/kg, ip) was administered 2 h after envenoming. Envenomation with Bj venom promoted tissue damage in the renal cortex (moderate degree, score 3) in 24 h associated with decreased glomerular and tubular function, which promoted proteinuria and polyuria. Doxy treatment prevented the increase in urinary volume in 3 times, the increase in plasma creatinine in 33%, the increase in blood urea-nitrogen accumulation in 65%, the increase in urinary Na⁺ excretion in 2 times, marked proteinuria and kidney cortex injury induced by Bj envenomation. Bj venom promoted increase in protein content (66%) and reduction of 45% (Na⁺+K⁺)-ATPase activity in the renal cortex. The enzyme was detected mainly in the luminal membrane. Doxy treatment was effective in preventing the mentioned alterations, maintaining (Na⁺+K⁺)-ATPase in the basolateral membranes.

RS, Barraviera B, Quintas LEM, Melo PA. A Novel Apilic Antivenom to Treat Massive, Africanized Honeybee Attacks: A Preclinical Study from the Lethality to Some Biochemical and Pharmacological Activities Neutralization

Massive, Africanized honeybee attacks have increased in Brazil over the years. Humans and animals present local and systemic effects after envenomation, and there is no specific treatment for this potentially lethal event. This study evaluated the ability of a new Apilic antivenom, which is composed of F(ab’)2 fraction of specific immunoglobulins in heterologous and hyperimmune equine serum, to neutralize A. mellifera venom and melittin, in vitro and in vivo, in mice. Animal experiments were performed in according with local ethics committee license (UFRJ protocol no. DFBCICB072-04/16). Venom dose-dependent lethality was diminished with 0.25–0.5 μL of intravenous Apilic antivenom/μg honeybee venom. In vivo injection of 0.1–1 μg/g bee venom induced myotoxicity, hemoconcentration, paw edema, and increase of vascular permeability which were antagonized by Apilic antivenom. Cytotoxicity, assessed in renal LLC-PK1 cells and challenged with 10 μg/mL honeybee venom or melittin, was neutralized by preincubation with Apilic antivenom, as well the hemolytic activity. Apilic antivenom inhibited phospholipase and hyaluronidase enzymatic activities. In flow cytometry experiments, Apilic antivenom neutralized reduction of cell viability due to necrosis by honeybee venom or melittin. These results showed that this antivenom is effective inhibitor of honeybee venom actions. Thus, this next generation of Apilic antivenom emerges as a new promising immunobiological product for the treatment of massive, Africanized honeybee attacks.

Occurrence of sulfated fucose branches in fucosylated chondroitin sulfate are essential for the polysaccharide effect preventing muscle damage induced by toxins and crude venom from Bothrops jararacussu snake

Snake envenoming is an important public health problem around the world, particularly in tropics. Beyond deaths, morbidity induced by snake venoms, such as myotoxicity, is of pivotal consequence to population. Bothrops jararacussu is the main venomous snake in southeast region of Brazil, and particularly presents strong myotoxic effect. The only available therapy, antibothropic antivenom, poorly affects venom-induced myotoxicity. The aim of this study is to assess the ability of fucosylated chondroitin sulfate (fucCS), a glycosaminoglycan with anticoagulant and antithrombotic properties, and its derivatives to inhibit toxic activities of B. jararacussu crude venom and its isolated toxins, named bothropstoxins (BthTX-I and BthTX-II). The in vitro myotoxic activities induced by crude venom, by BthTX-I alone and by toxins together were abolished by fucCS. Carboxyl reduction (fucCS-CR) kept this ability whereas defucosilation (defucCS) abrogates myoprotection. We observed the same pattern in the response of these polysaccharides in antagonizing the increase in plasma creatine kinase (CK) levels, the reduction of skeletal muscle CK content and the rise of myeloperoxidase (MPO) activity induced by crude venom and isolated toxins. FucCS inhibited edematogenic activity and partially prevented the reduction of total leukocytes in blood when pre-incubated with crude venom. Furthermore, the venom procoagulant effect was completely antagonized by increasing concentrations of fucCS, although this polyanion could stop neither the tail bleeding nor the skin hemorrhage induced by Bothrops jararaca venom. The B. jararacussu phospholipase, hyaluronidase, proteolytic and collagenase activities were inhibited in vitro. The results suggest that fucCS could be able to interact with both toxins, and it is able to inhibit BthTX-II phospholipase activity. Light microscopy of extensor digitorum longus muscle (EDL) muscle showed myoprotection by fucCS, once necrotic areas, edema and inflammatory cells were all decreased as compared to venom injection alone. Altogether, data show that fucCS was able to inhibit myotoxicity and inflammation induced by B. jararacussu venom and its phospholipase toxins, BthTX-I and BthTX-II. Thus, fucosylated chondroitin sulfate is a new polyanion with potential to be used as an adjuvant in the treatment of snakebites in the future.

Counteraction of Bothrops snake venoms by Combretum leprosum root extract and arjunolic acid

ETHNOPHARMACOLOGICAL RELEVANCE

Serotherapy against snakebite is often unavailable in some regions over Brazil, where people make use of plants from folk medicine to deal with ophidic accidents. About 10% of Combretum species have some ethnopharmacological use, including treatment of snakebites.

MATERIALS AND METHODS

We evaluated the ability of the extract of Combretum leprosum and its component arjunolic acid to reduce some in vivo and in vitro effects of Bothrops jararacussu and Bothrops jararaca venoms. The protocols investigated include phospholipase, proteolytic, collagenase, hyaluronidase, procoagulant, hemorrhagic, edematogenic, myotoxic and lethal activities induced by these venoms in Swiss mice.

RESULTS

Oral pre-treatment with arjunolic acid reduced the Bothrops jararacussu lethality in up to 75%, while preincubation prevented the death of all the animals. Hemoconcentration effect of Bothrops jararacussu venom was confirmed two hours after i.p. injection, while preincubation with arjunolic acid preserved the hematocrit levels. Both Combretum leprosum extract and arjunolic acid abolished the myotoxic action of Bothrops jararacussu venom. Preincubation of Bothrops jararacussu venom with the extract or arjunolic acid prevented the increase of plasma creatine kinase activity in mice. The hemorrhagic activity of Bothrops jararaca crude venom was reduced down to about 90% and completely inhibited by preincubation with 10 mg/kg or 100 mg/kg Combretum leprosum extract, respectively, while the preincubation and the pretreatment with 30 mg/kg of arjunolic acid reduced the venom hemorrhagic activity down to about 12% and 58%, respectively. The preincubation of the venom with both extract and 30 mg/kg arjunolic acid significantly reduced the bleeding amount induced by Bothrops jararacussu venom. The extract of Combretum leprosum decreased the edema formation induced by Bothrops jararacussu venom both in preincubation and pretreatment, but not in posttreatment. Similarly, arjunolic acid preincubated with the venom abolished edema formation, while pre- and posttreatment have been partially effective. Some enzymatic activities of Bothrops jararacussu and Bothrops jararaca venoms, i.e. phospholipase A2, collagenase, proteolytic and hyaluronidase activities, were to some extent inhibited by the extract and arjunolic acid in a concentration-dependent manner.

CONCLUSIONS

Altogether, our results show that Combretum leprosum extract can inhibit different activities of two important Brazilian snake venoms, giving support for its popular use in folk medicine in the management of venomous snakebites.

Abarema cochliacarpos extract decreases the inflammatory process and skeletal muscle injury induced by Bothrops leucurus venom

Snakebites are a public health problem, especially in tropical countries. However, treatment with antivenom has limited effectiveness against venoms' local effects. Here, we investigated the ability of Abarema cochliacarpos hydroethanolic extract (EAc) to protect mice against injection of Bothrops leucurus venom. Swiss mice received perimuscular venom injection and were subsequently treated orally with EAc in different doses. Treatment with EAc 100, 200, and 400 mg/kg reduced the edema induced by B. leucurus in 1%, 13%, and 39%, respectively. Although lower doses showed no antihypernociceptive effect in the Von Frey test, the higher dose significantly reduced hyperalgesia induced by the venom. Antimyotoxic activity of EAc was also observed by microscopy assessment, with treated muscles presenting preserved structures, decreased edema, and inflammatory infiltrate as compared to untreated ones. Finally, on the rotarod test, the treated mice showed better motor function, once muscle fibers were preserved and there were less edema and pain. Treated mice could stand four times more time on the rotating rod than untreated ones. Our results have shown that EAc presented relevant activities against injection of B. leucurus venom in mice, suggesting that it can be considered as an adjuvant in the treatment of envenomation.

Pulsed ultrasound therapy accelerates the recovery of skeletal muscle damage induced by Bothrops jararacussu venom

We studied the effect of pulsed ultrasound therapy (UST) and antibothropic polyvalent antivenom (PAV) on the regeneration of mouse extensor digitorum longus muscle following damage by Bothrops jararacussu venom. Animals (Swiss male and female mice weighing 25.0 ± 5.0 g; 5 animals per group) received a perimuscular injection of venom (1 mg/kg) and treatment with UST was started 1 h later (1 min/day, 3 MHz, 0.3 W/cm², pulsed mode). Three and 28 days after injection, muscles were dissected and processed for light microscopy. The venom caused complete degeneration of muscle fibers. UST alone and combined with PAV (1.0 mL/kg) partially protected these fibers, whereas muscles receiving no treatment showed disorganized fascicules and fibers with reduced diameter. Treatment with UST and PAV decreased the effects of the venom on creatine kinase content and motor activity (approximately 75 and 48%, respectively). Sonication of the venom solution immediately before application decreased the in vivo and ex vivo myotoxic activities (approximately 60 and 50%, respectively). The present data show that UST counteracts some effects of B. jararacussu venom, causing structural and functional improvement of the regenerated muscle after venom injury.

Aspectos clínico-patológicos do envenenamento botrópico experimental em equinos

Estudou-se as alterações clínico-patológicas e laboratoriais em equinos, inoculados experimentalmente com a peçonha de Bothropoides jararaca, Bothrops jararacussu, Bothrops moojeni e Bothropoides neuwiedi, com a finalidade de fornecer subsídios para o diagnóstico do envenenamento pela picada dessas. Os venenos liofilizados foram diluídos em 1ml de solução fisiológica e administrados a seis equinos, por via subcutânea, nas doses de 0,5 e 1mg/kg (B. jararaca), 0,8 e 1,6mg/kg (B. jararacussu), 0,205mg/kg (B. moojeni) e 1mg/kg (B. neuwiedi). Todos os equinos, menos os que receberam o veneno de B. jararacussu, morreram Os sinais clínicos iniciaram-se entre 8min e 2h10min após a inoculação. O período de evolução variou, nos quatro casos de êxito letal, de 24h41min a 70h41min, e nos dois equinos que se recuperaram foi de 16 dias. O quadro clínico, independente do tipo de veneno e das doses, caracterizou-se por aumento de volume no local da inoculação, arrastar da pinça do membro inoculado no solo, inquietação, apatia, diminuição da resposta aos estímulos externos, mucosas pálidas e hemorragias. Os exames laboratoriais revelaram anemia normocítica normocrômica com progressiva diminuição no número de hemácias, da hemoglobina e do hematócrito, e leucocitose por neutrofilia. Houve aumento de alamina aminotransferase, creatinaquinase, dehidrogenase láctica, ureia e glicose, bem como aumento do tempo de ativação da protrombina e do tempo de tromboplastina parcial ativada. Os achados de necropsia foram extensas hemorragias no tecido subcutâneo, com presença de sangue não coagulado e em boa parte associadas a edema (edema hemorrágico), que se estendia desde o local da inoculação até as regiões cervical, torácica, escapular e membro. Na periferia das áreas hemorrágicas havia predominantemente edema gelatinoso. Havia ainda presença de grande quantidade de líquido sanguinolento nas cavidades torácica, pericárdica e abdominal. Não foram encontradas alterações histológicas significativas.

Envenenamento experimental por Bothropoides jararaca e Bothrops jararacussu em ovinos: aspectos clínico-patológicos e laboratoriais

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).

Isolation and characterization of two new Lys49 PLA2s with heparin neutralizing properties from Bothrops moojeni snake venom

Among the proteins and peptides already characterized in Bothrops moojeni venom, two novel phospholipases A(2) (PLA(2)) have been purified and fully sequenced by ESI-MS/MS techniques. Both of them belong to the enzymatically non-active Lys49 variants of PLA(2). They consist of 122 amino acids and share a characteristic sequence in their C-terminal region composed of clusters of basic amino acids known to interact with heparin. Thus, as already established, heparin can be used as an antidote to antagonize some myotoxic PLA(2)s from venoms of Bothrops genus. The two PLA(2) variants were shown to interact in vitro with unfractionated heparin (UFH) and low molecular weight heparin (LMWH), neutralizing their anticoagulant properties. Although the influences of PLA(2)s from snake venoms on the blood coagulation system are known, their use to antagonize the anticoagulant effect of heparin in vitro or in vivo has never been proposed. These finding recommend diagnostic and therapeutic applications, which are currently investigated.