Effect of Bitis gabonica and Dendroaspis angusticeps snake venoms on apoptosis-related genes in human thymic epithelial cells

Certain environmental toxins permanently damage the thymic epithelium, accelerate immune senescence and trigger secondary immune pathologies. However, the exact underlying cellular mechanisms and pathways of permanent immune intoxication remain unknown. The aim of the present study was to demonstrate gene expressional changes of apoptosis-related cellular pathways in human thymic epithelial cells following exposure to snake venom from Bitis gabonica and Dendroaspis angusticeps. Methods: Snake venoms were characterized by analytical methods including reversed phase high-performance liquid chromatography and sodium dodecyl sulphate-polyacrylamide gel electrophoresis, then applied on human thymic epithelial cells (1889c) for 24 h at 10 μg/mL (as used in previous TaqMan Array study). Gene expressional changes restricted to apoptosis were assayed by TaqMan Array (Human Apoptosis Plate). Results: The most prominent gene expressional changes were shown by CASP5 (≈ 2.5 million-fold, confirmed by dedicated quantitative polymerase chain reaction) and CARD9 (0.016-fold) for B. gabonica, and BIRC7 (6.46-fold) and CASP1 (0.30-fold) for D. angusticeps. Conclusion: The observed apoptotic environment suggests that pyroptosis may be the dominant pathway through which B. gabonica and D. angusticeps snake venoms trigger thymic epithelial apoptosis following envenomation.(AU)

Alterações morfológicas induzidas pelo veneno da serpente PhilodryaS nattereri steindachner em ratos / Morphological changes induced by the snake venom from Philodryas nattereri Steindachner in rats

Philodryas nattererisnake is commonly distributed in arid and semiarid regions of northeast of Brazil. There is a shortage in the literature on the systemic effects of this venomin animals and humans. After 2h of intraperitoneally injection with differentdoses in rats, hemorrhagic zones in skin and the abdominal muscles were observed as well as presence of abundant erytrocytes in alveolar spaces and pulmonary congestion, hypereosinophilic cytoplasm in cells of cardiac muscle. Kidney and liver showed Histopathological changes. The snake venom of Philodryas nattereriwas capable of causing bleedind in different organs and morphological changes after poisoning.

A serpente Philodryas nattereri é comumente distribuída em regiões áridas e semi-áridas do nordeste do Brasil. Há escassez na literatura sobre os efeitos sistêmicos deste veneno em animais domésticos e humanos. Após 2h de injeção intraperitoneal com doses diferentes em ratos, foram observadas zonas hemorrágicas na pele e nos músculos abdominais, bem como a presença de eritrócitos abundantes em espaços alveolares, congestão pulmonar ecitoplasma hipereosinofílico em células do músculo estriado cardíaco. O rim e o fígado apresentaram alterações histopatológicas. O veneno da serpente Philodryas nattereri foi capaz de causar sangramento em diferentes órgãos e mudanças morfológicas após o envenenamento.

Alterações morfológicas induzidas pelo veneno da serpente PhilodryaS nattereri steindachner em ratos / Morphological changes induced by the snake venom from Philodryas nattereri Steindachner in rats

Philodryas nattererisnake is commonly distributed in arid and semiarid regions of northeast of Brazil. There is a shortage in the literature on the systemic effects of this venomin animals and humans. After 2h of intraperitoneally injection with differentdoses in rats, hemorrhagic zones in skin and the abdominal muscles were observed as well as presence of abundant erytrocytes in alveolar spaces and pulmonary congestion, hypereosinophilic cytoplasm in cells of cardiac muscle. Kidney and liver showed Histopathological changes. The snake venom of Philodryas nattereriwas capable of causing bleedind in different organs and morphological changes after poisoning.(AU)

A serpente Philodryas nattereri é comumente distribuída em regiões áridas e semi-áridas do nordeste do Brasil. Há escassez na literatura sobre os efeitos sistêmicos deste veneno em animais domésticos e humanos. Após 2h de injeção intraperitoneal com doses diferentes em ratos, foram observadas zonas hemorrágicas na pele e nos músculos abdominais, bem como a presença de eritrócitos abundantes em espaços alveolares, congestão pulmonar ecitoplasma hipereosinofílico em células do músculo estriado cardíaco. O rim e o fígado apresentaram alterações histopatológicas. O veneno da serpente Philodryas nattereri foi capaz de causar sangramento em diferentes órgãos e mudanças morfológicas após o envenenamento.(AU)

Cytotoxicity of Southeast Asian snake venoms

Cytotoxicity of venoms from eleven medically important snakes found in Southeast Asia (Naja kaouthia, Naja siamensis, Naja sumatrana, Ophiophagus hannah, Bungarus candidus, Bungarus fasciatus, Enhydrina schistosa, Calloselasma rhodostoma, Trimeresurus purpureomaculatus and Tropidolaemus sumatranus) was determined, based on the MTS cytotoxicity assay, which determines the survival of viable cells in monolayer MDCK and Vero cell cultures upon exposure to the snake venoms. Snake venom toxicity was expressed as the venom dose that killed 50% of the cells (CTC50) under the assay conditions. Venoms of C. rhodostoma (2.6 µg/mL, 1.4 µg/mL) and O. hannah were the most cytotoxic (3.8 µg/mL, 1.7 µg/mL) whereas N. siamensis venom showed the least cytotoxicity (51.9 µg/mL, 45.7 µg/mL) against Vero and MDCK cells, respectively. All the viper venoms showed higher cytotoxic potency towards both Vero and MDCK cell lines, in comparison to krait and cobra venoms. E. schistosa did not cause cytotoxicity towards MDCK or Vero cells at the tested concentrations. The cytotoxicity correlates well with the known differences in the composition of venoms from cobras, kraits, vipers and sea snakes.(AU)

Intradermal injection of Bothrops cotiara venom in mice in an experimental wound model

Bothropic envenomation induces hemorrhage, coagulant disturbances and necrosis. Regarding therapies against the local damage caused by the venom, there is little information on tissue changes until the complete healing. In the current study, local damage was evaluated by examination of morphological inflammatory alterations, mast cell count, and analysis of collagen deposition. Bleeding was evident four hours after inoculation. After 24 hours, a large area of injury appeared presenting disorganized tissue, significant hemorrhage and acute inflammation. After three days, the damaged area was extensive, with a large amount of inflammatory cells and the presence of scab. In seven days, healing and reepithelization process started. And, 21 days later, the epithelium showed less infiltration and no skin appendages. The number of mast cells was similar to control after four hours, with a drop of 50 percent at 24 hours, followed by an increase until the 21st day. No differences of collagen deposition were observed among experimental groups. Taken together, wound healing after intradermal injection of Bothrops cotiara venom in mice follows similar parameters to wounds caused by other bothropic venoms. The present work reveals the importance of experimental wound models to the study of neutralizing agents against venom toxins.(AU)

Neutralization of pharmacological and toxic activities of Bothrops jararacussu snake venom and isolated myotoxins by Serjania erecta methanolic extract and its fractions

Most of the snakebites recorded in Brazil are caused by the Bothrops genus. Given that the local tissue damage caused by this genus cannot be treated by antivenom therapy, numerous studies are focusing on supplementary alternatives, such as the use of medicinal plants. Serjania erecta has already demonstrated anti-inflammatory, antiseptic and healing properties. In the current study, the aerial parts of S. erecta were extracted with methanol, then submitted to chromatographic fractionation on a Sephadex LH20 column and eluted with methanol, which resulted in four main fractions. The crude extract and fractions neutralized the toxic activities of Bothrops jararacussu snake venom and isolated myotoxins (BthTX-I and II). Results showed that phospholipase A2, fibrinogenolytic, myotoxic and hemorrhagic activities were inhibited by the extract. Moreover, the myotoxic and edematous activities induced by BthTX-I, and phospholipase A2 activity induced by BthTX-II, were inhibited by the extract of S. erecta and its fraction. The clotting time on bovine plasma was significantly prolonged by the inhibitory action of fractions SF3 and SF4. This extract is a promising source of natural inhibitors, such as flavonoids and tannins, which act by forming complexes with metal ions and proteins, inhibiting the action of serineproteases, metalloproteases and phospholipases A2.(AU)

Fatal bothropic snakebite in a horse: a case report

The present study reports a snakebite in a horse in the state of Pará, Brazil. At initial evaluation the animal was reluctant to walk and had tachycardia, tachypnea, severe lameness, bleeding on the pastern and swelling around the left hind leg. Blood samples from the bleeding sites, took on the first day, showed leukocytosis and neutrophilia, whereas biochemical values of urea and creatinine were significantly increased. The chosen treatment was snake antivenom, fluid therapy, antibiotics, anti-inflammatory agents and diuretic drugs. On the fourth day of therapy, the hematological values were within normal parameters. There was improvement related to the clinical lameness and swelling of the limb. However, a decrease in water intake and oliguria were observed. On the seventh day the animal died. Necropsy revealed areas of hemorrhagic edema in the left hind limb and ventral abdomen; the kidneys presented equimosis in the capsule, and when cut they were wet. Moreover, the cortex was pale, slightly yellow and the medullary striae had the same aspect. Based on these data, we concluded that the snakebite in the present study was caused by Bothrops spp. and that renal failure contributed to death.(AU)

Biochemical comparison of venoms from young Colombian Crotalus durissus cumanensis and their parents

Crotalus durissus cumanensis, a rattlesnake endemic to Colombia and Venezuela, is considered one of the most lethal snake species in Latin America. The aim of the present study was to compare the protein content and biological activity of the venom obtained from eight specimens of C. durissus cumanensis, namely two adults from different localities of Colombia and six offspring born in captivity. Protein profiles of crude venoms were analyzed by SDS-PAGE and RP-HPLC, and biological activities were evaluated for lethality, edema, defibrination, hemolytic and coagulant activities to assess individual venoms of adults and a pool of young snake venoms. Transient edema appeared rapidly after venom inoculation, whereas hemorrhagic effect was not observed. Differences in protein profiles, lethality, hemolytic, coagulant and defibrinating activities between both adult snake venoms were observed; those from the mother snake exhibited higher activities. Venoms from young snakes were similar to the one obtained from the mother, but the coagulant effect was stronger in offspring venoms. Notably, biological effects of the father snake venom were not comparable to those previously described for C. durissus cumanensis from Venezuela and C. durissus terrificus from Brazil, confirming the high variability of the venom from Crotalus species.(AU)