Pro-inflammatory response and hemostatic disorder induced by venom of the coral snake Micrurus tener tener IN C57BL/6 mice

Exploring the Safety of Pllans-II and Antitumoral Potential of Its Recombinant Isoform in Cervical Cancer Therapy

The antitumor potential of proteins from snake venoms has been studied in recent decades, and evidence has emerged that phospholipases A2 can selectively attack cells of various types of tumors. Previous results have shown that phospholipase A2 "Pllans-II," isolated from Porthidium lansbergii lansbergii snake venom, displayed antitumoral activity on cervical cancer and did not alter the viability of non-tumorigenic cells. However, until now, there was no evidence of its safety at the local and systemic levels, nor had experiments been developed to demonstrate that its production using recombinant technology allows us to obtain a molecule with effects similar to those generated by native phospholipase. Thus, we evaluated the impact caused by Pllans-II on murine biomodels, determining whether it induced local hemorrhage or increased pro-inflammatory and liver damage markers and histological alterations in the liver and kidneys. Additionally, the protein was produced using recombinant technology using a pET28a expression vector and the BL21 (DE3) Escherichia coli strain. Equally, its enzymatic activity and anticancer effect were evaluated on cervical cancer lines such as HeLa and Ca Ski. The results demonstrated that Pllans-II did not generate hemorrhagic activity, nor did it increase the pro-inflammatory cytokines IL-6, IL-1B, or TNF-α at doses of 3.28, 1.64, and 0.82 mg/kg. There was also no evidence of organ damage, and only ALT and AST increased in mild levels at the two highest concentrations. Additionally, the recombinant version of Pllans-II showed conservation in its catalytic activity and the ability to generate death in HeLa and Ca Ski cells (42% and 23%, respectively). These results demonstrate the innocuity of Pllans-II at the lowest dose and constitute an advance in considering a molecule produced using recombinant technology a drug candidate for selective attacks against cervical cancer.

Effect of gamma-irradiated honey bee venom on gene expression of inflammatory and anti-inflammatory cytokines in mice

In this study, the effect of gamma-irradiated honey bee venom (doses of 0, 2, 4, 6, and 8 kGy, volume of 0.1 ml and concentration of 0.2 mg/ml) was evaluated on the reduction of allergen compounds and the gene expression of inflammatory and anti-inflammatory cytokines in mice. Hence, edema activity induced by the bee venom irradiated at 4, 6, and 8 kGy was reduced, compared with the control group and that irradiated at 2 kGy. In contrast, the paw edema induced by the bee venom irradiated at 8 kGy increased, compared with 4 and 6 kGy. At all the time periods, there was a significant decrease in the gene expression of interferon gamma (IFN-γ), interleukin 6 (IL-6), and interleukin 10 (IL-10) in the bee venoms irradiated at 4, 6, and 8 kGy, compared with the control group and that irradiated at 2 kGy. In contrast, there was an increase in the gene expression of IFN-γ and IL-6 in the bee venom irradiated at 8 kGy, compared with those irradiated at 4 and 6 kGy. Therefore, gamma irradiation at 4 and 6 kGy reduced the gene expression of cytokines at each time period by decreasing the allergen compounds of honey bee venom.

The edematogenic effect of Micrurus lemniscatus venom is dependent on venom phospholipase A2 activity and modulated by non-neurogenic factors

Coral snakes mainly cause neurotoxic symptoms in human envenomation, but experimental studies have already demonstrated several pharmacological activities in addition to these effects. This investigation was carried out with the aim of evaluating (1) non-neurogenic mechanisms involved in the inflammatory response induced by Micrurus lemniscatus venom (MLV) in rat hind paws, (2) participation of PLA₂ in this response, and (3) neutralizing efficiency of commercial anti-elapid antivenom on edema. MLV promoted a rapid, significant increase in vascular permeability, influx of leukocytes, and disorganization of collagen bundles, as demonstrated by histological analysis. Several pretreatments were applied to establish the involvement of inflammatory mediators in MLV-induced edema (5 µg/paw). Treatment of animals with chlorpromazine reduced MLV-induced edema, indicating participation of TNF-α. However, the inefficiency of other pharmacological treatments suggests that eicosanoids, leukotrienes, and nitric oxide have no role in this type of edema formation. In contrast, PAF negatively modulates this venom-induced effect. MLV was recognized by anti-elapid serum, but this antivenom did not neutralize edema formation. Chemical modification of MLV with p-bromophenacyl bromide abrogated the phospholipase activity and markedly reduced edema, demonstrating PLA₂ participation in MLV-induced edema. In conclusion, the non-neurogenic inflammatory profile of MLV is characterized by TNF-α-mediated edema, participation of PLA₂ activity, and down-regulation by PAF. MLV induces an influx of leukocytes and destruction of collagen fibers at the site of its injection.

Qualitative and Quantitative Study of the Changes in the Ultrastructure of Mammalian Adrenal Cortex Caused by the Venezuelan Tigra Mariposa (Bothrops venezuelensis) Snake Venom

The damage of the adrenal gland by snake venoms needs to be clarified. Lethality (LD50) of Bothrops venezuelensis (Bv) venom was established by intraperitoneally mice injections. Preparation of specimens for transmission electron microscopy samples from cortex adrenal gland biopsies at 3, 6, and 24 h was processed. The quantitative description by the principal component analysis (PCA) of the adrenal gland was as follows: thickening of the capillary endothelium, area of the capillary lumen, cell nucleus area, enlargement of the perinuclear space, number of mitochondria, area of the mitochondria, number of mitochondrial cristae, number of cristae per mitochondrial unit, and tubular diameter of the smooth endoplasmic reticulum (SER). Sections of the adrenal cortex, after 3 h postinjection with Bv venom showed in the cortical cells: mitochondria with tubular cristae and slightly swollen SER cisternae, nucleus with variable heterochromatin content, irregular edges, and swollen nuclear envelope. After 6 h, cells with swollen nucleus envelope, electron dense lipids and mitochondria with loss of their cristae were observed. Myelin figures, close to the microvilli of the cortical cell, multivesicular bodies, swollen profiles of the SER, and electron dense lipid drops were noticed. After 24 h, thickening of the endothelial wall, fenestrae and projections into the capillary lumen, loss of the mitochondrial cristae, destruction of the capillary and the plasma membrane of the cortical cell, multivesicular body, SER loss, and an enlargement of the perinuclear space were detected. In the quantitative PCA, there were significant changes after the venom treatments.

Contribution of endothelial cell and macrophage activation in the alterations induced by the venom of Micrurus tener tener in C57BL/6 mice

An acute inflammatory response, cellular infiltrates, anemia, hemorrhage and endogenous fibrinolysis activation were previously described in C57BL/6 mice injected with M. tener tener venom (Mtt). As the endothelium and innate immunity may participate in these disturbances and due to our poor understanding of the alterations produced by these venoms when the neurotoxic component is not predominant, we evaluated the effects in an in vitro model. At 24 h, the release of pro-inflammatory mediators was detected in peritoneal macrophages. At different times, the release of pro-inflammatory (TNF-α, IL-6, NO and E-Selectin), pro-coagulant (vWF and TF) and pro-fibrinolytic (uPA) mediators were seen in liver sinusoidal endothelial cells (LSECs). These results suggest that Mtt venom activates macrophages and endothelium, thus inducing the release of mediators, such as TNF-α, that orchestrate the acute inflammatory response and the later infiltration of mononuclear cells into liver in C57BL/6 mice. In addition, endothelium activation promotes TF expression, which may in turn modulate the inflammatory and hemostatic response. These findings suggest crosstalk between inflammation and hemostasis in the alterations observed in Micrurus envenomation, where the neurotoxic manifestations do not predominate.