Correlation between blood pressure, cytokines and nitric oxide in conscious rabbits injected with Leiurus quinquestriatus quinquestriatus scorpion venom

Tityus stigmurus venom causes genetic damage in blood and testicular cells and affects the number and morphology of gametogenic lineage cells in mice

Scorpion envenomation represents an important health problem in many parts of the world, due to the high number and severity of accidents. Recent studies demonstrated that some species can produce venoms with genetic damage potential. Here, we evaluated whether Tityus stigmurus venom causes genetic damage in blood and testicular cells of Swiss mice. We also analyzed the effect of the venom on the number of spermatogenic lineage cells. Five groups of mice received 0.387 mg/kg of the venom, intraperitoneally; one group received saline solution (control group). Blood and testicular cells were collected for comet assay and histological analysis at different times after treatment (1, 2, 6, 12, and 48 h). Blood was also collected 48 h after treatment for the micronucleus test in erythrocytes. Histological analysis was performed by counting cells of the spermatogenic lineages; the nuclear area of elongated spermatocytes was also evaluated. Treatment with the venom induced DNA damage that endured from 1 h to 48 h, as confirmed by the comet assay. The micronucleus test demonstrated that the venom induced mutations in erythrocytes. The number of spermatogonia and rounded spermatids decreased in some groups; the number of elongated spermatids increased, and their nuclear size decreased 1 h after treatment. Genetic damage can be caused directly by the venom, but we suggested that reactive oxygen species that result from inflammatory process caused by the envenomation may have an important role in the DNA damage. Genetic damage and apoptosis may explain the changes in the number of spermatogenic cells. Furthermore, the decrease in nuclear area may result from chromatin loss. Genetic damage in testicular cells, associated with alterations in the number and morphology of spermatogenic cells, can result in reproduction disorders in animals, or humans, stung by T. stigmurus.

Scorpion Venom: Detriments and Benefits

Scorpion venom may cause severe medical complications and untimely death if injected into the human body. Neurotoxins are the main components of scorpion venom that are known to be responsible for the pathological manifestations of envenoming. Besides neurotoxins, a wide range of other bioactive molecules can be found in scorpion venoms. Advances in separation, characterization, and biotechnological approaches have enabled not only the development of more effective treatments against scorpion envenomings, but have also led to the discovery of several scorpion venom peptides with interesting therapeutic properties. Thus, scorpion venom may not only be a medical threat to human health, but could prove to be a valuable source of bioactive molecules that may serve as leads for the development of new therapies against current and emerging diseases. This review presents both the detrimental and beneficial properties of scorpion venom toxins and discusses the newest advances within the development of novel therapies against scorpion envenoming and the therapeutic perspectives for scorpion toxins in drug discovery.

Renal Alterations Induced by the Venom of Colombian Scorpion Centruroides Margaritatus

BACKGROUND

Scorpion venom causes renal injury and affects vascular ion-channels function. Centruroides margaritatus scorpion is found in Colombia and is frequently the cause of envenomation accidents; however, its renal impact has never been investigated.

OBJECTIVE

To evaluate the effects of C. margaritatus venom (CmV) on renal parameters using isolated rat kidney and renal cell culture models.

METHODS

Wistar rats (n = 5, weighing 240-300 g) were first perfused with Krebs-Henseleit solution containing 6 g 100 mL-1 bovine serum albumin. After 30 minutes, the kidneys were perfused with CmV to a final concentration of 10 μgmL-1; evaluation was performed by measuring Perfusion Pressure (PP), Renal Vascular Resistance (RVR), Urinary Flow (UF), Glomerular Filtration Rate (GFR), and percentage of electrolyte tubular transport. Moreover, kidney histological analyses and cell cytotoxicity in renal tubule epithelial cells (MDCK) and proximal tubular cells (LLC-MK2) were assessed.

RESULTS

CmV increased PP and RVR 60 min after perfusion. On the other hand, UF, GFR, and the percentages of sodium, potassium and chloride tubular transport decreased after experimental envenomation. UF dropped after 120 min, while GFR and percentage of electrolyte tubular transport diminished after 60, 90 and 120 min. CmV was not toxic to MDCK cell line but reduced the viability of LLC-MK2 cells at concentrations ranging from 6.25 to 200 μgmL-1. Histological analyses disclosed hydropic degeneration, edema, and protein deposits. Flow cytometry disclosed that cell death occurred predominantly by necrosis.

CONCLUSION

Our results suggest that C. margaritatus venom can trigger renal impairment, mainly in the proximal kidney tubule.

Vasodilator and hypotensive effects of the spider peptide Lycosin-I in vitro and in vivo

Lycosin-I, a spider peptide isolated from the venom of the spider Lycosa singoriensis, has anti-bacteria and anti-cancer properties in organisms. However, cardiovascular effects of Lycosin-I have not been studied. In this study, we investigated for the first time the vasodilator and hypotensive effects of Lycosin-I and the possible mechanisms, in order to develop a promising treatment for hypertension-related diseases. For in vitro experiments, thoracic aortas were isolated, and divided into two groups, endothelium-intact and endothelium-denuded aortic rings. Lycosin-I induced a remarkable dose-dependent relaxation in endothelium-intact aortic rings pre-treated with phenylephrine (p < 0.05), while it showed no obvious vasodilator effects in endothelium-denuded aortic rings (p > 0.05). The vasodilator effects of Lycosin-I were significantly weakened by a nitric oxide synthase (NOS) inhibitor, L-NAME (p < 0.001) and a selective inhibitor of nitric oxide (NO)-sensitive soluble guanylate cyclase (sGC), ODQ (p < 0.05), respectively. The levels of endothelial nitric oxide synthase (eNOS) phosphorylation and the NO production were significantly higher in human umbilical vascular endothelial cells pre-cultured with Lycosin-I than the control (p < 0.001), determined via western blot analysis and ozone-chemiluminescence technology. For in vivo experiments, arterial and venous catheters were inserted for mean arterial pressure (MAP) recording and drug administration in anaesthetized spontaneously hypertensive rats. Lycosin-I caused a transient drop of MAP 2 min after the administration compared with the control (p < 0.001). In conclusion, Lycosin-I has the potential to be an anti-hypertensive drug by endothelium-dependent vasodilatation, in which eNOS and NO-sensitive sGC are two main involved factors.

Selected scorpion toxin exposures induce cytokine release in human peripheral blood mononuclear cells

A cytokine screening on human peripheral blood mononuclear cells (PBMCs) stimulated with selected scorpion toxins (ScTx's) was performed in order to evaluate their effect on human immune cells. The ScTx's chosen for this report were three typical buthid scorpion venom peptides, one with lethal effects on mammals Centruroides suffussus suffusus toxin II (CssII), another, with lethal effects on insects and crustaceans Centruroides noxius toxin 5 (Cn5), and one more without lethal effects Tityus discrepans toxin (Discrepin). A Luminex multiplex analysis was performed in order to determine the amounts chemokines and cytokines IL-1β, IL-2, IL-4, IL-5, IL-6, IL-10, IL-12-p40, IL-13, interferon alpha (IFN-α), interferon gamma (IFN-γ), tumor necrosis factor alpha TNF-α, and interferon-inducible protein-10 (IP-10) secreted from human PBMCs exposed to these toxins. Although, the ScTx Cn5 is not lethal for mammals, it was able to induce the secretion of cytokines IL-1β, IL-6, and TNF-α, IL-10 and IP-10 in comparison to the lethal CssII, which was able to induce only IP-10 secretion. Discrepin also was able to induce only IP-10. Interestingly, only low amounts of interferons α and β were induced in the presence of the ScTx's assayed. In a synergic experiment, the combination of Discrepin and Cn5 displayed considerable reverse effects on induction of IL-1β, IL-6, IL-10 and TNF-α, but they had a slight synergic effect on IP-10 cytokine production in comparison with the single effect obtained with the Cn5 alone. Thus, the results obtained suggest that the profile of secreted cytokines promoted by ScTx Cn5 is highly related with a cytokine storm event, and also it suggests that the mammalian lethal neurotoxins are not solely responsible of the scorpion envenomation symptomatology.

Impact of scorpion venom as an acute stressor on the neuroendocrine-immunological network

Although immunomodulatory property and many other pharmaceutical applications of scorpion venom have been addressed before, no studies were reported about its application as a neuroimmunomodulator at therapeutic dose. In this study, we conceptualized the property of scorpion venom, capable of inducing the acute pain and neurotoxicity can cause acute stress resulting in the modulation of immune cells through HPA axis. The whole venom from Hottentotta rugiscutis, a widely seen scorpion in the region of eastern Karnataka, was extracted and injected a single dose of 1 mg/kg b.w. to Swiss albino mice and then erythrocytes and leukogram were measured. Whole brain AChE activity, corticosterone, cytokines and NO levels in plasma were also evaluated at various time points. Hrv didn't show any histopathological changes in the lymphoid organs and at the site of injection. However, lymphocytes and neutrophils did get altered at 2 h post-injection. Plasma corticosterone, cytokine levels such as IL-1β, IL-6, TNF-α and IL-10 and the AChE activity were significantly increased in a time-dependent manner. Based on these results, it may be predicted, Hrv's ability to cause acute stress resulted in the activation of HPA axis, which stimulates the release of glucocorticoid hormones which in turn elicits the immunomodulation of leukocytes by altering the levels of pro and anti-inflammatory cytokines. Thus, we can conclude, the impact of acute stress induced by Hrv can intercommunicate the signals between neuroendocrine-immune systems.

Scorpion sting nephropathy

Scorpion envenomations are ubiquitous, but nephropathy is a rare manifestation, reported mainly from the Middle East and North Africa. Rapid venom redistribution from blood, delayed excretion from the kidneys, direct toxicity of venom enzymes, cytokine release and afferent arteriolar constriction have been seen in experimental animals. Haemoglobinuria, acute tubular necrosis, interstitial nephritis and haemolytic–uraemic syndrome have been documented in human victims of scorpion envenomation. Epidemiology, venom components and toxins, effects on the laboratory mammals especially the kidneys and reports of renal failure in humans are reviewed in this article.

Naja naja karachiensis envenomation: biochemical parameters for cardiac, liver, and renal damage along with their neutralization by medicinal plants

Naja naja karachiensis envenomation was found to hit more drastically heart, liver, and kidneys. 400 μg/kg of venom-raised moderate serum levels of ALT (72 ± 4.70 U/L, 0.1 > P > 0.05), AST (157 ± 24.24 U/L, 0.1 > P > 0.05), urea (42 ± 3.08 mg/dL, 0.05 > P > 0.02), creatinine (1.74 ± 0.03 mg/dL, 0.01 > P > 0.001), CK-MB (21 ± 1.5 U/L, 0.05 > P > 0.02), and LDH (2064 ± 15.98 U/L, P < 0.001) were injected in experimental rabbits. However, lethality was enhanced with 800 μg/kg of venom in terms of significant release of ALT (86 ± 5.0 U/L, 0.05 > P > 0.02), AST (251 ± 18.2 U/L, 0.01 > P > 0.001), urea (57.6 ± 3.84 mg/dL, 0.02 > P > 0.01), creatinine (2.1 ± 0.10 mg/dL, 0.02 > P > 0.01), CK-MB (77 ± 11.22 U/L, 0.05 > P > 0.02), and LDH (2562 ± 25.14 U/L, P ≪ 0.001). Among twenty-eight tested medicinal plant extracts, only Stenolobium stans (L.) Seem was found the best antivenom (P > 0.5) compared to the efficacy of standard antidote (ALT = 52.5 ± 3.51 U/L, AST = 69.5 ± 18.55 U/L, urea = 31.5 ± 0.50 mg/dL, creatinine = 1.08 ± 0.02 mg/dL, CK-MB = 09 ± 0.85 U/L, and LDH = 763 ± 6.01 U/L). Other plant extracts were proved less beneficial and partly neutralized the toxicities posed by cobra venom. However, it is essential in future to isolate and characterize bioactive compound(s) from Stenolobium stans (L.) Seem extract to overcome the complications of snake bite.

The effects of a chactoid scorpion venom and its purified toxins on rat blood pressure and mast cells histamine release

The effect of the venom of the Chactoid family of scorpions on blood pressure was scantly investigated and was addressed in the present study using the venom of the Israeli scorpion, Scorpio maurus palmatus. Blood pressure in rats was monitored via cannulated femoral artery, while venom and toxins were introduced into femoral vein. Venom injection elicited a biphasic effect, expressed first by a fast and transient hypotensive response, which lasted up to 10 min, followed by a hypertensive response, which lasted up to one hour. It was found that these effects resulted from different venom components. Phospholipase A₂ produced the hypotensive effect, while a non-enzymatic neurotoxic polypeptide fraction produced the hypertensive effect. Surprisingly, the main neurotoxic polypeptide to mice had no effect on blood pressure. In vitro experiments indicated that the hypertensive factors caused histamine release from the peritoneal mast cells, but this effect is assumed to be not relevant to their in vivo effect. In spite of the cytotoxic activity of phospholipase A₂, it did not release histamine. These findings suggest that the effects of venom and isolated fractions on blood pressure parameters are mediated by different mechanisms, which deserve further pharmacological investigation.

Effects of atropine and propranolol on lung inflammation in experimental envenomation: comparison of two buthidae venoms

Background

Previous works had shown that scorpion venom induced neurotransmitter elevation and an inflammatory response associated with various anatomo-pathological modifications. The most dangerous scorpions species in Algeria responsible for these effects are Androctonus australis hector (Aah) and Androctonus amoreuxi (Aam).

Results

Comparison of the physiopathological effects induced by the two venoms showed differences in the kinetic of cytokine release and in lung injury.

The lung edema was only observed in response to Aah venom and it was correlated with cell infiltration. In order to better understand the involved mechanism in inflammatory response, we used two antagonists, atropine (non-selective muscarinic antagonist) and propranolol (β adrenergic antagonist), which lead to a decrease of cell infiltration but has no effect on edema forming.

Conclusion

These results suggest another pathway in the development of lung injury following envenomation with Aam or Aah venom.

Target organ identification of jellyfish envenomation using systemic and integrative analyses in anesthetized dogs

Proper treatment of jellyfish envenomed patients can be successfully achieved only from an understanding of the overall functional changes and alterations in physiological parameters under its envenomation. The majority of previous investigations on jellyfish venoms have covered only a couple of parameters at a time. Unlike most other fragmentary jellyfish studies, we employed an integrative toxicological approach, including hemodynamics, clinical chemistry and hematology analyses, using N. nomurai jellyfish venom (NnV) in dogs. After the baseline measurements for mean arterial pressure (MAP), cardiac output (CO) and heart rate (HR), NnV was intravenously administered to the dogs at doses of 0.1 or 0.3mg/kg body weight. The dogs showed significant decreases in MAP (-27.4±3.7 and -48.1±9.9 mmHg), CO (-1.1±0.1 L/min and -1.0±0.2 L/min), and HR (-4.5±0.3 and -9.9±3.1 beats/min) comparing with the respective baseline controls. The onset of systemic hypotension and bradycardia occurred within 1 min of NnV injection and they lasted for 1-35 min, depending on the NnV doses. Interestingly, serum biochemical analyses of envenomed dogs exhibited dramatic increases of alkaline phosphatase (ALP), creatine phosphokinase (CPK), alanine aminotransferase (ALT) and aspartate aminotransferase (AST), indicating its possible target organs. In conclusion, we have demonstrated simultaneously, for the first time, the multiple organ toxicities (cardiotoxic, myotoxic and hepatotoxic) of a scyphozoan jellyfish venom. Based on these results, an integrative toxinological approach using dogs appears to be effective in predicting jellyfish venom toxicities and designing their therapeutic strategies. We expect this method can be applied to other jellyfish venom research as well.

Comparative study between peripherally and centrally acting sublethal and lethal doses of Leiurus quinquestriatus scorpion venom in rabbits: The usefulness of the sodium channel blocker lidocaine

BACKGROUND

Scorpion envenomation is common among desert dwellers, affecting several systems and resulting in multiple organ dysfunction (MOD) or failure (MOF), mainly due to their action on Na(+) channels. Although scorpion venoms toxins do not pass the blood brain barrier, their CNS effects are prominent, occurring in conjunction with, or as an aftermath of peripheral actions of the venom.

OBJECTIVE

To determine the ability of venom of the common scorpion Leiurus quinquestriatus (LQQ) to induce MOD or MOF when injected into rabbits in micro quantities centrally (intracerebroventricularly, i.c.v.) or macro amounts peripherally (s.c. or i.v.). Also, to assess if the Na(+) channel blocker lidocaine can protect rabbits from the resultant manifestations.

METHODS

Rabbits were injected with LQQ venom centrally or peripherally, in either sublethal or lethal doses, and MOD or MOF determined by assessing: cardiac output (CO), estimated hepatic blood flow (EHBF), biochemical parameters indicative of cardiac/hepatic/renal and pancreatic functions, blood pressure (BP), survival, lung/body index (LBI, indicative of pulmonary edema), and/or histological changes in hearts, lungs, livers plus kidneys. In pre-treatment experiments, lidocaine was injected 40 min before venom and protective ability examined.

RESULTS

LQQ venom in sublethal doses caused comparable significant reductions (vs control) in CO and EHBF when injected i.c.v. (2 μg kg(-1)) or s.c. (0.2 mg kg(-1)). Both routes caused gradual dose-related enhanced levels of creatine kinase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, creatinine, glucose and amylase, indicating MOD. Also, characteristic venom-induced changes in BP were evident after lethal doses of venom i.v. (0.5 mg kg(-1)) or i.c.v. (3 μg kg(-1)). Histological changes in the organs plus LBI were comparable after i.c.v. and i.v. venom injection, with animals ultimately exhibiting MOF. Lidocaine (1 mg kg(-1) i.v., then infusion 50 μg kg(-1) min(-1), 30 min before venom), protected the animals from MOF evoked by lethal doses of the venom (whether injected centrally or peripherally), as evidenced by the amelioration of the venom's effects on blood pressure, LBI, survival and multiple organ histopathological manifestations.

CONCLUSION

LQQ venom, whether injected centrally or peripherally caused comparable systemic dose-dependent MOD or MOF, with the latter attenuated by the Na(+) channel blocker lidocaine, indicating a role for Na(+) channels.

Scorpion venom and the inflammatory response

Scorpion venoms consist of a complex of several toxins that exhibit a wide range of biological properties and actions, as well as chemical compositions, toxicity, and pharmacokinetic and pharmacodynamic characteristics. These venoms are associated with high morbility and mortality, especially among children. Victims of envenoming by a scorpion suffer a variety of pathologies, involving mainly both sympathetic and parasympathetic stimulation as well as central manifestations such as irritability, hyperthermia, vomiting, profuse salivation, tremor, and convulsion. The clinical signs and symptoms observed in humans and experimental animals are related with an excessive systemic host inflammatory response to stings and stings, respectively. Although the pathophysiology of envenomation is complex and not yet fully understood, venom and immune responses are known to trigger the release of inflammatory mediators that are largely mediated by cytokines. In models of severe systemic inflammation produced by injection of high doses of venom or venoms products, the increase in production of proinflammatory cytokines significantly contributes to immunological imbalance, multiple organ dysfunction and death. The cytokines initiate a cascade of events that lead to illness behaviors such as fever, anorexia, and also physiological events in the host such as activation of vasodilatation, hypotension, and increased of vessel permeability.

Tityus fasciolatus envenomation induced cardio-respiratory alterations in rats

The present study characterized envenomation in young rats by Tityus fasciolatus, an endemic scorpion to Central Brazilian and state of Minas Gerais. Electrocardiographic examinations were performed prior to treatment and every 5 min during the first 30 min after envenomation. The cardiac blood profile [creatine kinase, CK isoenzyme MB, lactate dehydrogenase, aspartate aminotransferase and troponina] together with macroscopic and microscopic alterations in the lungs and heart were evaluated. Envenomated animals showed ECG changes suggesting electrolytic imbalance, myocarditis and venom interference on the conduction tissue. Biochemical analyses indicated myocardial damage with high levels of CK, CK-MB and LDH. Macroscopic and microscopic findings included detection of pulmonary haemorrhages. In conclusion, T. fasciolatus venom leads to acute cardio-respiratory changes in young rats.