Increased plasma levels of IL-1beta, IL-6, IL-8, IL-10 and TNF-alpha in patients moderately or severely envenomed by Tityus serrulatus scorpion sting

Tityus bahiensis scorpion venom injected to dams during pregnancy affects some cytokines of fetuses

Due to the high incidence of scorpion stings in Brazil, pregnant women are among the possible victims. Cytokines are important during the pregnancy, and scorpion venoms can change their release. We evaluated the levels of some cytokines in the fetuses after the treatment of pregnant rats with the Tityus bahiensis scorpion venom. The concentration of some of them is altered and can be responsible for the effects previously observed on innate reflexes, and the physical and behavioral development of the offspring.

Electrophysiological characterization of the first Tityus serrulatus alpha-like toxin, Ts5: Evidence of a pro-inflammatory toxin on macrophages

Tityus serrulatus (Ts) venom is composed of mainly neurotoxins specific for voltage-gated K(+) and Na(+) channels, which are expressed in many cells such as macrophages. Macrophages are the first line of defense invasion and they participate in the inflammatory response of Ts envenoming. However, little is known about the effect of Ts toxins on macrophage activation. This study investigated the effect of Ts5 toxin on different sodium channels as well as its role on the macrophage immunomodulation. The electrophysiological assays showed that Ts5 inhibits the rapid inactivation of the mammalian sodium channels Nav1.2, Nav1.3, Nav1.4, Nav1.5, Nav1.6 and Nav1.7. Interestingly, Ts5 also inhibits the inactivation of the insect Drosophila melanogaster sodium channel (DmNav1), and it is therefore classified as the first Ts α-like toxin. The immunological experiments on macrophages reveal that Ts5 is a pro-inflammatory toxin inducing the cytokine production of tumor necrosis factor (TNF)-α and interleukin (IL)-6. On the basis of recent literature, our study also stresses a possible mechanism responsible for venom-associated molecular patterns (VAMPs) internalization and macrophage activation and moreover we suggest two main pathways of VAMPs signaling: direct and indirect. This work provides useful insights for a better understanding of the involvement of VAMPs in macrophage modulation.

Effects of Tityus serrulatus scorpion venom on thromboelastogram in rats

Thromboelastometry was used to evaluate blood coagulation in anesthetized rats after intravenous administration of Tityus serrulatus scorpion venom (Tx). Tracheostomy followed by catheterization of the left jugular vein and right carotid artery were performed for Tx or Ringer's lactate solution injection and blood sample harvesting, respectively. Blood samples were obtained at the beginning of the experiments (baseline) and at two, five, 15, 30, and 60 min after intoxication. The following coagulation parameters were analyzed: CT (Clotting Time), CFT (Clotting Formation Time), Alpha Angle (α), MCF (Maximum Clot Firmness) and TPI (Thrombodynamic Potential Index). Toxin-induced hypercoagulability was demonstrated at the 15 and 60 min. We hypothesize Tx-induced hypercoagulability and enhanced clot formation could be explained by catecholamine release, systemic inflammatory response, and complement system activation, at least in the first hour after envenomation. Further studies are needed to determine the molecular mechanism of Tx-induced coagulopathy.

Ipomoea asarifolia neutralizes inflammation induced by Tityus serrulatus scorpion venom

ETHNOPHARMACOLOGICAL RELEVANCE

Envenoming caused by scorpion sting is a serious public health problem. In Brazil, 13,038 accidents caused by venomous animals have been reported. Of this total, 53% of the cases and 14 deaths were caused by scorpions. Furthermore, Tityus serrulatus (Buthidae) is the most dangerous scorpion due to the high toxicity of its venom. The treatment is the common supportive therapy and the serum therapy, but some people do not have access to both therapies and seek healing through the use of medical plants.

AIM OF THE STUDY

This study evaluated the ability of the crude extract and fractions from the leaves of Ipomoea asarifolia in neutralizing the main biological effects caused by Tityus serrulatus envenoming in mice.

MATERIALS AND METHODS

BALB/c mice were pretreated (i.v.) with 100 μλ of aqueous extracts and fractions dichloromethane, ethyl acetate, and n-butanol (CH₂Cl₂, EtOAc, and n-BuOH, respectively) of Ipomoea asarifolia, rutin or saline. Then, the animals received 100 μλ (i.p.) of venom of Tityus serrulatus (0.8 mg/kg). After six hours, the peritoneal lavage was performed with PBS and the number cells were determined using a Neubauer chamber. The supernatants were collected for determination of cytokines, such as IL-6, IL-12, and IL-1β.

RESULTS

The aqueous extract, fractions and rutin, at all doses, significantly reduced cell migration, which was endorsed by the reduction of the levels of certain cytokines.

CONCLUSION

This is the first study that demonstrated the potential effect of Ipomoea asarifolia against inflammation caused by Tityus serrulatus venom, suggesting that these extracts and/or their bioactive molecules, especially the flavonoid rutin, have potential use in the therapy of this envenomation.

Convulsive and Neurodegenerative Effects in Rats of Some Isolated Toxins from the Tityus bahiensis Scorpion Venom

Despite Tityus bahiensis being one of the most dangerous scorpions in Brazil, there are few studies about the effects of its venom, which acts mainly on the central nervous system. Previous studies demonstrated the convulsive ability of this venom. The present work aimed to study the hippocampal effects in rats of some toxins isolated from pool V, which induces a pronounced epileptogenic effect. The pool was separated by reverse-phase HPLC, and the peaks with higher yield (Tb V-1, V-5, V-24, V-27, and V-28) were used in the experiments. Cannulae and electrodes were implanted in the hippocampus of male Wistar rats (240–250 g). The animals were divided into six groups that received intracerebral injection of toxin solution (1 or 2 μg/μL) or Ringer solution (control group), and they were submitted to behavioral, electrographic, and histological analysis. All toxins studied evoked electrographic and behavioral epileptic-like activity to different degrees. Moreover, the toxins V-1, V-24, and V-28 caused significant neuronal loss in CA4 ipsi- and contralateral hippocampal areas. These results suggest that toxins from T. bahiensis scorpion, when injected into the hippocampus, are able to act directly on the central nervous system inducing convulsive and neurodegenerative effects.

Scorpion peptides: potential use for new drug development

Several peptides contained in scorpion fluids showed diverse array of biological activities with high specificities to their targeted sites. Many investigations outlined their potent effects against microbes and showed their potential to modulate various biological mechanisms that are involved in immune, nervous, cardiovascular, and neoplastic diseases. Because of their important structural and functional diversity, it is projected that scorpion-derived peptides could be used to develop new specific drugs. This review summarizes relevant findings improving their use as valuable tools for new drugs development.

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.

Neuropathophysiological effect and immuno-inflammatory response induced by kaliotoxin of androctonus scorpion venom

OBJECTIVE

Kaliotoxin (KTX) is a neurotoxin purified from Androctonus scorpion venom. Purification and pharmacological and immunological characterization of this neurotoxin has been extensively studied, but its biological effects have not. The ability of KTX to induce neuropathophysiological and immuno-inflammatory effects was investigated.

METHODS

NMRI mice were injected with a sublethal dose of KTX (20 ng/20 g of body weight) or saline solution via the intra-cerebro-ventricular route. Tissue damage and immunological biomarkers such as eosinophil peroxidase (EPO), myeloperoxidase (MPO), and nitric oxide (NO) were analyzed in serum, brain, lung, and heart tissue. Protein levels, LDH, and CPK activities were also determined in serum 24 h after injection.

RESULTS

In this study, KTX injection induced severe alterations in the cerebral cortex, myocardium, and pulmonary parenchyma. Tissue damage was correlated with seric increase in creatine kinase and lactate dehydrogenase activities. KTX also induced an immuno-inflammatory response distinguished by cell infiltration characterized by a significant increase in EPO and MPO activities in the brain, heart, and lungs. This infiltration was also associated with an increase in albumin, α-, β-, and γ-globulin fractions, and NO release.

CONCLUSION

KTX binding to its targets in CNS (Kv1.1 and Kv1.3 channels) may induce severe modifications in the structure and function of various organs associated with the activation of immuno-inflammatory reactions.

Ts6 and Ts2 from Tityus serrulatus venom induce inflammation by mechanisms dependent on lipid mediators and cytokine production

Inflammatory mediators are thought to be involved in the systemic and local immune response induced by the Tityus serrulatus scorpion envenomation. New functional aspects of lipid mediators have recently been described. Here, we examine the unreported role of lipid mediators in cell recruitment to the peritoneal cavity after an injection with Ts2 or Ts6 toxins isolated from the T. serrulatus scorpion venom. In this report, we demonstrate that following a single intraperitoneal (i.p.) injection of Ts2 or Ts6 (250 μg/kg) in mice, there was an induction of leukocytosis with a predominance of neutrophils observed at 4, 24, 48 and 96 h. Moreover, total protein, leukotriene (LT)B(4), prostaglandin (PG)E(2) and pro-inflammatory cytokine levels were increased. We also observed an increase of regulatory cytokines, including interleukin (IL)-10, after the Ts2 injection. Finally, we observed that Ts2 or Ts6 injection in 5-lipoxygenase (LO) deficient mice and in wild type (WT) 129sv mice pre-treated with LTs and PGs inhibitors (MK-886 and celecoxib, respectively) a reduction the influx of leukocytes occurs in comparison to WT. The recruitment of these cells demonstrated a phenotype characteristic of neutrophils, macrophages, CD4 and CD8 lymphocytes expressing GR1+, F4/80+, CD3+/CD4+ and CD3+/CD8+, respectively. In conclusion, our data demonstrate that Ts2 and Ts6 induce inflammation by mechanisms dependent on lipid mediators and cytokine production. Ts2 may play a regulatory role whereas Ts6 exhibits pro-inflammatory activity exclusively.

TNF-α involvement in insulin resistance induced by experimental scorpion envenomation

BACKGROUND

Scorpion venom induces systemic inflammation characterized by an increase in cytokine release and chemokine production. There have been few experimental studies assessing the effects of scorpion venom on adipose tissue function in vivo.

METHODOLOGY/PRINCIPAL FINDINGS

To study the adipose tissue inflammation (ATI) induced by Androctonus australis hector (Aah) venom and to assess possible mechanisms of ATI, mice (n = 6, aged 1 month) were injected with Aah (0.45 mg/kg), toxic fraction of Aah (FTox-G50; 0.2 mg/kg) or saline solution (control). Inflammatory responses were evaluated by ELISA and cell sorting analyses in adipose tissue 45 minutes and 24 hours after injection. Quantitative real-time PCR was used to assess the regulation of genes implicated in glucose uptake. The titers of selected inflammatory cytokines (IL-1β, IL-6 and TNF-α) were also determined in sera and in insulin target tissues. The serum concentration of IL-1β rose 45 minutes after envenomation and returned to basal level after 24 hours. The pathophysiological effects of the venom after 24 hours mainly involved M1-proinflammatory macrophage infiltration in adipose tissue combined with high titers of IL-1β, IL-6 and TNF-α. Indeed, TNF-α was strongly induced in both adipose tissue and skeletal muscle. We studied the effects of Aah venom on genes implicated in insulin-stimulated glucose uptake. Insulin induced a significant increase in the expression of the mRNAs for hexokinase 2 and phosphatidylinositol 3-kinase in both skeletal muscle and adipose tissue in control mice; this upregulation was completely abolished after 24 hours in mice envenomed with Aah or FTox-G50.

CONCLUSIONS/SIGNIFICANCE

Our findings suggest that Aah venom induces insulin resistance by mechanisms involving TNF-α-dependent Map4k4 kinase activation in the adipose tissue.

Scorpion Venom Peptides Accelerate Hematopoietic Recovery of Myelosuppression in Irradiated Mice

Sublethally irradiated mice were administered with scorpion venom peptides (SVP) or with PBS in the saline control group, 3 days before and 7 consecutive days after irradiation. Hematopoietic recovery was assessed by bone marrow (BM) cell proliferation index (PI) and colony forming unit-granulocyte/macrophage (CFU-GM), spleen weight index (SI) and thymus weight index (TI), colony-forming unit-spleen (CFU-S) and peripheral leukocyte counts. In addition, IL-1α and SCF levels in BM, IL-6 and GM-CSF levels in serum were determined. In SVP treated groups, PI was improved dramatically versus control mice on day 22 after irradiation. The number of CFU-GM colonies in all SVP treated groups was higher than the control groups. The difference of the number of CFU-GM colonies between SVPV group (0.2 mg/kg) and the control was significant on day 5 and 10 after irradiation ( p < 0.05). SVPIV (0.2 mg/kg) could activate the CFU-S formation on day 10 after irradiation. SI was in peak value on day 15 after irradiation in all groups and the SI value of SVPV treated group was higher than control group ( p < 0.05). Our results suggest that SVP may be valuable natural peptides that relieve myelosuppression caused by radiation. The effect of SVP accelerating the hematopoietic recovery was potentially through a mechanism of stimulating the release of cytokines.

Serrumab: a human monoclonal antibody that counters the biochemical and immunological effects of Tityus serrulatus venom

In Brazil, the species Tityus serrulatus is responsible for the most severe cases of scorpion envenomation. There is currently a need for new scorpion anti-venoms that are more effective and less harmful. This study attempted to produce human monoclonal antibodies capable of inhibiting the activity of T. serrulatus venom (TsV), using the Griffin.1 library of human single-chain fragment-variable (scFv) phage antibodies. Four rounds of phage antibody selection were performed, and the round with the highest phage antibody titer was chosen for the production of monoclonal phage antibodies and for further analysis. The scFv 2A, designated serrumab, was selected for the production and purification of soluble antibody fragments. In a murine peritoneal macrophage cell line (J774.1), in vitro assays of the cytokines interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-10 were performed. In male BALB/c mice, in vivo assays of plasma urea, creatinine, aspartate transaminase, and glucose were performed, as well as of neutrophil recruitment and leukocyte counts. It was found that serrumab inhibited the TsV-induced increases in the production of IL-6, TNFα, and IL-10 in J774.1 cells. The in vivo inhibition assay showed that serrumab also prevented TsV-induced increases in the plasma levels of urea, creatinine, aspartate transaminase, and glucose, as well as preventing the TsV-induced increase in neutrophil recruitment. The results indicate that the human monoclonal antibody serrumab is a candidate for inclusion in a mixture of specific antibodies to the various toxins present in TsV. Therefore, serrumab shows promise for use in the production of new anti-venom.

Perfis clínico e hematológico de camundongos submetidos ao envenenamento escorpiônico experimental por Tityus fasciolatus

Estudou-se o quadro clínico do veneno decorrente do envenenamento por Tityus fasciolatus e sua ação refletida nos componentes hematológicos no modelo murino. Para o estudo do perfil hematológico, foram utilizados 54 camundongos Swiss CF1, machos, com 30g, distribuídos em três grupos (G) (n=18) inoculados via subcutânea com: 50µL de PBS (G1); 24µg de veneno de T. fasciolatus (G2) e 8µg de veneno de T. serrulatus (G3). Cada grupo foi subdividido em três subgrupos (n=6) de acordo com o momento da coleta de sangue que foi estipulada em uma, oito e 24h após a inoculação do veneno, e foram realizados o hemograma e a dosagem de proteínas totais e fracionadas. O veneno de T. fasciolatus na dose de 24µg causou piloereção, comportamento nociceptivo, secreção nasal e oral acentuada, dispneia, prurido na face e reflexos exacerbados. No exame hematológico, foram observadas policitemia relativa e leucocitose com linfocitose.

Immune cells recruitment and activation by Tityus serrulatus scorpion venom

Despite several studies showed that the Tityus serrulatus scorpion venom (Tsv) induces an inflammatory response, just a few have investigated the effect of the venom on the immune response. Therefore, the aim of this study was to evaluate alterations of venom application on lymphoid organs and on the recruitment and activation of cells and also on the cytokine production. Swiss male mice (2-3 months, 20-25 g) received a non-lethal dose of crude Tsv (200 μg/kg), diluted in sterile PBS by subcutaneous route. Control animals received only sterile PBS. The animals were sacrificed after 30, 120 and 360 min. The inflammatory parameters studied were skin histology at the site of venom application, leukocyte count, and blood cytokine levels (IL-6, IL-10, and TNF-α). Inguinal lymph node, spleen and bone marrow cellularity was determined for evaluation of the Tsv effect on immune system organs. The results showed that Tsv caused no local inflammation, but it induced an increase of blood neutrophils and serum IL-6, TNF-α and IL-10. After 360 min of envenomation there was a reduction in the cells number from peritoneum and spleen, but there was an increase in the cell number from lymph nodes. In conclusion, the Tsv induces systemic alterations characterized by changes in the cell number in lymphoid organs, increase pro and anti-inflammatory cytokines.

Scorpion envenomation and antivenom therapy

Scorpion envenomation is a dangerous and common global event that can result in a variety of toxic clinical effects. These are typically managed with supportive care or antivenom. Antivenom use is controversial because of conflicting evidence of effectiveness for adrenergic toxicity. However, both controlled and uncontrolled studies have shown that antivenom is effective in resolving neuromotor toxicity associated with envenomations by the scorpions of genus Centruroides.

Tityus serrulatus venom and toxins Ts1, Ts2 and Ts6 induce macrophage activation and production of immune mediators

Scorpion envenomation induces a systemic immune response, and neurotoxins of venom act on specific ion channels, modulating neurotransmitter release or activity. However, little is known about the immunomodulatory effects of crude venom from scorpion Tityus serrulatus (TsV) or its toxins (Ts1, Ts2 and Ts6) in combination with lipopolysaccharide (LPS). To investigate the immunomodulatory effects of TsV and its toxins (Ts1, Ts2 and Ts6), J774.1 cells were stimulated with different concentrations (25, 50 and 100 μg/mL) of venom or toxins pre-stimulated or not with LPS (0.5 μg/mL). Macrophage cytotoxicity was assessed, and nitric oxide (NO) and cytokine production were analyzed utilizing the culture supernatants. TsV and its toxins did not produce cytotoxic effects. Depending on the concentrations used, TsV, Ts1 and Ts6 stimulated the production of NO, interleukin (IL)-6 and tumor necrosis factor (TNF)-α in J774.1 cells, which were enhanced under LPS co-stimulation. However, LPS + Ts2 inhibited NO, IL-6 and TNF-α production, and Ts2 alone stimulated the production of IL-10, suggesting an anti-inflammatory activity for this toxin. Our findings are important for the basic understanding of the mechanisms involved in macrophage activation following envenomation; additionally, these findings may contribute to the discovery of new therapeutic compounds to treat immune-mediated diseases.

Scorpion envenomation among children: clinical manifestations and outcome (analysis of 685 cases)

Our objective was to characterize both epidemiologically and clinically manifestations after severe scorpion envenomation and to define simple factors indicative of poor prognosis in children. We performed a retrospective study over 13 years (1990-2002) in the medical intensive care unit (ICU) of a university hospital (Sfax-Tunisia). The diagnosis of scorpion envenomation was based on a history of scorpion sting. The medical records of 685 children aged less than 16 years who were admitted for a scorpion sting were analyzed. There were 558 patients (81.5%) in the grade III group (with cardiogenic shock and/or pulmonary edema or severe neurological manifestation [coma and/or convulsion]) and 127 patients (18.5%) in the grade II group (with systemic manifestations). In this study, 434 patients (63.4%) had a pulmonary edema, and 80 patients had a cardiogenic shock; neurological manifestations were observed in 580 patients (84.7%), 555 patients (81%) developed systemic inflammatory response syndrome (SIRS), and 552 patients (80.6%) developed multi-organ failure. By the end of the stay in the ICU, evolution was marked by the death in 61 patients (8.9%). A multivariate analysis found the following factors to be correlated with a poor outcome: coma with Glasgow coma score ≤ 8/15 (odds ratio [OR] = 1.3), pulmonary edema (OR = 2.3), and cardiogenic shock (OR = 1.7). In addition, a significant association was found between the development of SIRS and heart failure. Moreover, a temperature > 39°C was associated with the presence of pulmonary edema, with a sensitivity at 20.6%, a specificity at 94.4%, and a positive predictive value at 91.7%. Finally, blood sugar levels above 15 mmol/L were significantly associated with a heart failure. In children admitted for severe scorpion envenomation, coma with Glasgow coma score ≤ 8/15, pulmonary edema, and cardiogenic shock were associated with a poor outcome. The presence of SIRS, a temperature > 39°C, and blood sugar levels above 15 mmol/L were associated with heart failure.

Specific activation of human neutrophils by scorpion venom: a flow cytometry assessment

Acute lung injury following envenomation by Tityus scorpion species is due in part to activation of the inflammatory response leading to release of cytotoxic leukocyte-derived products, including cytokines and possibly reactive oxygen species (ROS). Tityus zulianus envenomation in Venezuela produces cardiorespiratory complications and death by lung injury whereas stings by Tityus discrepans produce mainly gastrointestinal and pancreatic alterations. To ascertain the role played by granulocytes in the envenomation by T. zulianus (TzV) and T. discrepans (TdV), human peripheral blood neutrophils, eosinophils, and monocytes were exposed to scorpion venoms (0.001-5 μg/mL) and the kinetics (5-15 min) of peroxide production determined by flow cytometry, using 2',7'-dichlorodihydrofluorescein diacetate (succinimidyl ester) as a fluorescent substrate. TzV induced a significantly (p<0.01) more potent increase in peroxide production in neutrophils (for 5 and 10 min of incubation), and to a lesser extent in monocytes (5-15 min), compared to TdV. TzV induced necrosis in neutrophils at doses higher than 5 μg/mL. No effect was observed on eosinophils, suggesting that TzV specifically targets neutrophil intracellular ROS production. The TzV-stimulated pathway is protein kinase C-dependent because it was almost completely (>90%) abolished by staurosporine. The stimulatory effect is associated with the lowest molecular mass venom peptides as gel filtration fractions TzII and TzIII significantly enhanced peroxide production. The combined used of the intracellular ROS agonist, phorbol myristate acetate (PMA), and TzV produced a modest but significant increase in peroxide production suggesting the possibility of overlapping signaling cascades amongst PMA and TzV. Up-regulation of intracellular neutrophil ROS production may be an important in vivo target for TzV which could have a role to play in the cardiorespiratory complications elicited after envenomation by this species.

Intrahippocampal injection of TsTX-I, a beta-scorpion toxin, causes alterations in electroencephalographic recording and behavior in rats

AIMS

TsTX-I scorpion toxin, also known as γ-toxin, is a β-toxin which binds to site 4 of the sodium channel, shifting its activation potential. There are few studies about its pharmacological action in the central nervous system. The objective of this work was to determine the electroencephalographic, behavioral and histopathological effects of intrahippocampal injection of TsTX-I.

MAIN METHODS

Rats were anesthetized and fitted with cannulae for injection into the hippocampus and with electrodes for cerebral recording. The animals were treated with Ringer solution, some doses of TsTX-I, DMSO 0.1% or veratridine. Behavioral and electrographic recordings were observed for 4 hours after the injection. After 7 days, the rats were perfused, and their brains removed for histological analysis.

KEY FINDINGS

Increasing doses of the toxin evoked epileptic-like discharges, wet dog shakes, and in some cases hind limb paralysis and intense respiratory difficulty followed by death. The histopathological analysis demonstrated no cell loss. Animals injected with veratridine developed epileptiform activity in the electrographic recording and neuronal loss.

SIGNIFICANCE

The results suggest that TsTX-I toxin may be responsible, at least in part, for the epileptic and behavioral effects observed with the crude venom, and although veratridine and TsTX-I act on Na-channel, the differences between them are remarkable, demonstrating that toxins can have different functional effects depending on the site of action in the channel. Thus, animal neurotoxins are often highly selective and may be useful for the identification of the sequence of events underlying neurotransmission.

Assessment of biochemical and hematological parameters in rats injected with Tityus serrulatus scorpion venom

The aim of this work was to evaluate the hematological changes induced by Tityus serrulatus venom (TsV). Blood of Wistar rats was collected 0.5, 2, 6 and 24 h after i.p. injection of TsV (0.5 mg/kg) or saline (controls). Two additional groups were injected with 0.67 mg/kg and 0.25 mg/kg of TsV and the blood was collected after 0.5 and 2 h, respectively. The results showed an increase on hematocrit (Ht), red blood cells (RBC) count, hemoglobin concentration (Hb), albumin and total protein, mainly 2-6 h after envenoming. Increase in serum activities of amylase, creatine kinase and aspartate aminotransferase were also observed, indicating tecidual damages. Hyperglycemia was observed at all times analyzed, as a consequence of catecholamine release. No significant changes were detected in the urea, [Na(+)] and [Ca(2+)], but an increase of [Mg(2+)], [K(+)] and conductivity was observed. TsV induced a reduction of erythrocytes osmotic fragility as consequence of dehydration and increase in plasma electrolytes concentration, as evidenced by its higher conductivity. This study demonstrated that TsV is able to induce severe hematological changes, that appear within the first hours after envenoming, justifying the seeking of medical attention as soon as possible to avoid worsening of clinical symptoms.

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.

Effects of in utero exposure to Tityus bahiensis scorpion venom in adult rats

The toxicity of Tityus bahiensis scorpion venom is well known, but there are little data about the damage in offspring of dams that were exposed to the venom during pregnancy. The objective of this work was to determine the toxic effects of venom in adult offspring of Wistar rats exposed to venom in utero. Dams were divided into a control group, subcutaneously injected with saline solution on the 10th (GD10) and 16th (GD16) days, and two experimental groups, subcutaneously injected with venom (2.5mg/kg) on GD10 or GD16, respectively. Adult offspring were evaluated according to behavioral development and neuronal integrity in the hippocampus. Tests performed in the activity box and in the enriched environment demonstrated that males from GD10 had motor decrease. Females from GD10 showed a depressive-like state and were more anxious, as demonstrated by the forced swimming test and social interaction. The plus-maze discriminative avoidance task demonstrated that GD16 males had lower levels of anxiety. The number of neuronal cells was decreased in CA1, CA3 and CA4 hippocampal areas of males and females from GD10 group and in CA1 of females and CA4 of males from GD16 group. Thus, we conclude that venom exposure in pregnant dams causes subtle alteration in the behavioral and neuronal development of offspring in adult life in a gender-dependent manner.

Comparative study between the protective effects of Saudi and Egyptian antivenoms, alone or in combination with ion channel modulators, against deleterious actions of Leiurus quinquestriatus scorpion venom

This study compared efficacy of two polyvalent antivenoms (Saudi Arabian and Egyptian), against lethality and pathophysiological changes of Leiurus quinquestriatus quinquestriatus (LQQ) scorpion venom in mice. Additionally, the study examined whether treatment with selected ion channel modulators, lidocaine, nimodipine or amiodarone would be effective, alone or combined with the antivenoms. The protein concentration of the Saudi antivenom was 1/3 of Egyptian, indicating lesser immunogenicity, while both preservative contents were within limits. In immunodiffusion experiments, both exhibited prominent precipitin bands indicating high concentrations of specific antibodies. Neutralizing capacities (60-70 LD(50)) stated on labels were confirmed. Both antivenoms significantly (P < 0.001) prolonged survival time (from 26.9 +/- 1.18 min, 100% dead with venom to 224-300 min, 0-30% dead) of envenomed mice, whether injected iv before or 5 min after venom. Injection of either antivenom plus ion channel modulators, gave comparable results to that observed in mice treated with antivenoms alone. The Na(+) channel blocker lidocaine and the Ca(2+) channel blocker nimodipine on their own significantly protected the animals (P < 0.05), but to a lesser extent. The two antivenoms, significantly ameliorated the venom-evoked changes in serum LDH (P < 0.001) and CKMB (P < 0.01) plus cardiac TNFalpha and nitrate/nitrite levels (P < 0.001). When combined with lidocaine or nimodipine, the effects were not greater than antivenom alone. Moreover, the antivenoms ameliorated characteristic venom-evoked changes in the isolated perfused Langendorff hearts. Lidocaine and amiodarone were more effective than nimodipine. In Conclusion both Saudi and Egyptian antivenoms protected mice from the pathological and lethal effects of LQQ scorpion. Sodium and calcium channel blockers, lidocaine and nimodipine, may be useful when antivenoms are not available.

Central effects of Tityus serrulatus and Tityus bahiensis scorpion venoms after intraperitoneal injection in rats

A great number of studies on scorpion venoms associate their effects to the autonomic nervous system, and few data are available about their action on the central nervous system (CNS). The aim of this work was to evaluate some central effects after intraperitoneal injection of Tityus serrulatus or T. bahiensis scorpion venoms. The hippocampal concentration of some neurotransmitters and their metabolites were determined. Electroencephalographic and behavioral observations were performed, and all brains were removed for histopathological analysis of hippocampal areas. Both venoms induced electrographic and behavioral alterations despite T. bahiensis venom affects less the electrographic activity than T. serrulatus venom. Neurochemical analysis demonstrated no alteration in the extracellular levels of almost all the neurotransmitters evaluated, at least in the hippocampus, and no neuronal loss in this area was observed. Meanwhile, extracellular concentration of HVA increased up to 10 times in approximately 1/3 of the animals of both groups. Scorpion venoms seem to exert a small but important central effect. More studies in this field are necessary because they may be useful in developing new strategies to reduce the damage caused by scorpion stings.

Hemograma de cães submetidos ao envenenamento experimental por Tityus serrulatus

Avaliou-se o hemograma de 12 cães adultos, saudáveis (14,2±5,4kg) após a inoculação de veneno do escorpião amarelo (Tityus serrulatus). Os animais foram distribuídos em dois grupos (G), com seis em cada: os do GI foram usados como controle e receberam 0,5mL de salina tamponada com fosfato (PBS) por via subcutânea (SC) na face medial da coxa esquerda (FMCE), e os do GII receberam veneno liofilizado do T. serrulatus (250µg/kg) diluído em PBS por via SC na FMCE. Foram realizadas colheitas de sangue com anticoagulante EDTA a 10% antes da inoculação do veneno (T0) e após 2h, (T1), 6h (T2), 12h (T3), 24h (T4), 48h (T5) e 72h (T6), para contagem de eritrócitos, leucócitos e plaquetas em aparelho contador eletrônico e esfregaços sanguíneos para contagem diferencial de leucócitos. Houve aumento significativo (P<0,05) dos valores de eritrócitos, volume globular e hemoglobina 2h e 6h após o envenenamento, devido à contração esplênica decorrente da dor local causada pelo veneno e pela liberação de catecolaminas. Foi observada leucocitose por aumento significativo (P<0,05) de neutrófilos e linfócitos 2h e 6h após o envenenamento. Concluiu-se que o veneno de Tityus serrulatus na dose de 250µg/kg, é capaz de aumentar os valores do eritrograma e do leucograma dos cães, provavelmente devido à dor local, com liberação de catecolaminas.

Pathophysiological effects of Androctonus australis hector scorpion venom: tissue damages and inflammatory response

In this study, the effects of sublethal dose of Androctonus australis hector (Aah) venom on the enzymatic activities (creatine phospho-kinase and lactate dehydrogenase) and histopathological changes of heart and lungs' organs were determined 24h following envenoming NMRI mice. The effects of Aah venom on the lytic activity of the complement system, plasma cytokine rates (IL1-beta, IL-6, TNF-alpha, IL-4 and IL-10) and the peripheral blood cell infiltration were also studied. Microscopically, treated animals showed severe myocardial edema, hemorrhages and necroses and severe acute bronchopneumonia with alveolar edema and hemorrhages. High serum levels of lactate dehydrogenase and creatine kinase correlate to the tissue lesions. The results showed fast kinetics of production of pro-inflammatory (IL1-beta, IL-6, TNF-alpha) and anti-inflammatory (IL-4 and IL-10) cytokines at 30min in blood sera. An increase in serum lytic activity of envenomed animals and leucocytosis in peripheral blood with predominance of mononuclear and neutrophil cells were also observed. In conclusion, the results reported in the present study suggest that pathophysiological manifestations of Aah envenomation may be mediated sequentially or simultaneously by cytokines and the complement system, which in turn activate leukocyte to produce tissue damage.