In recent years, extensive research has delved into the pathophysiology of local reactions triggered by Bothrops snake venoms. Even though antivenom works well at reducing death and systemic effects, it is still not very effective in treating local reactions because the venom works so quickly, and antivenom cannot fix injuries that have already been triggered. This might be attributed to certain molecules amplifying the venom-induced innate response. While evidence suggests endogenous mediators at the venom site play a role in this envenomation, in Brazil, concurrent use of anti-inflammatories or other drugs associated with the antivenom remains uncommon. The aim of this study was to determine how various inflammatory mediators affected the leukocyte-endothelium interaction (LEI) following a B. jararaca bite. According to our findings, nitric oxide and cyclooxygenase pathway eicosanoids significantly contribute to alteration of LEI induced by B. jararaca venom. Conversely, lipoxygenase-mediated eicosanoids, histamine, or serotonin had minimal participation. Markedly, treatment with dexamethasone alongside antivenom mitigated alterations of LEI induced by the B. jararaca snake venom. The limited efficacy of the antivenom in managing Bothrops venom-induced local reactions emphasizes the critical need for supplementary treatments to enhance therapeutic outcomes.

Myotoxic phospholipases A₂ are responsible for many clinical signs in envenomation by Bothropssnakes. A new myotoxic acidic PLA₂ Asp 49 was isolated from Colombian Bothrops asper venom. It was isolated by high efficiency liquid chromatography and named BaCol PLA₂. It had a molecular weight of 14180.69 Da and an isoelectric point of 4.4. The complete sequenceobtained by cDNA cloning, with access number in the gene bank MF319968; this sequenceevidenced a mature product of 124 amino acids with Asp in 49 position. In vivoassaysin mice demonstrated profuse oedemaand myotoxicity evidenced by increase of creatinakinasa in plasma and severe and diffuse damage to the muscular fibers, further vacuolization and hyalinization necrosis of the sarcoplasm showed by histopathology with hematoxylin and eosin staining of gastrocnemius muscle. In vitro studies showed cell membrane damage without phosphatidylserine exposure, an early apoptosis hallmark. Further BaCol PLA₂ evidenced high indirect hemolytic activityand moderate anticoagulant action. The toxin showed homology with others acidic PLA₂ isolated from Bothrops venoms, including one isolated from B. asper of Costa Rica. Unlike this, BaCol PLA₂ was myotoxic.

Background: Clinical cases reports with snake accidents show that venom bite induces increased oxidative stress including several markers of lipid peroxidation and other oxidative stress marker in plasma. Methods: The main findings of this work were performed with BthTx-II on paw edema of animals treated with the toxin and biochemical measurement of COX-2, PGE2, MDA and the effects of peroxiredoxin inhibitors on edema and myotoxicity were also evaluated. Results: The results show that edema and myotoxocity induced by PLA2 (BthTx-II) induces a strong mobilization of arachidonic acid and an increase in cellular oxidative stress as measured by increased malondialdehydo (MDA) concentration and protein carbonylation. Thus, these findings establish the strong link between oxidative stress, arachidonic acid mobilization and that these events may explain the presence of oxidative stress markers in snake-bitten patients. Experiments performed with animals previously treated with commercially purchased inhibitors showed enzymes such as thioredoxin (TXN), thioredoxin reductase (TXNRD) and other glutathione (GSH)-related antioxidant defenses could play an essential role controlling and defining the end of edema on the late phase of PLA2 BthTx-II-induced process. Conclusion. This study showed that thioate-dependent antioxidant enzymes play an important role in resolving the edema induced by BthTx-II.