1
|
Hmaidi R, Ksouri A, Benabderrazek R, Antonietti V, Sonnet P, Gautier M, Bouhaouala-Zahar B, Ouadid-Ahidouch H. The Pharmacological and Structural Basis of the AahII–NaV1.5 Interaction and Modulation by the Anti-AahII Nb10 Nanobody. Front Pharmacol 2022; 13:821181. [PMID: 35295326 PMCID: PMC8918821 DOI: 10.3389/fphar.2022.821181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 01/17/2022] [Indexed: 11/13/2022] Open
Abstract
Scorpion α-toxins are neurotoxins that target the fast inactivation mechanism of voltage-gated sodium (NaV) channels leading to several neuro- and cardiotoxic effects in mammals. The toxin AahII is the most active α-toxin from the North African scorpion Androctonus australis Hector that slows the fast inactivation of NaV channels. To fight scorpion envenomation, an anti-AahII nanobody named NbAahII10 (Nb10) was developed. The efficiency of this nanobody has been evaluated in vivo on mice, but its mechanism of action at the cellular level remains unknown. Here we have shown that AahII toxin slows the fast inactivation of the adult cardiac NaV1.5 channels, expressed in HEK293 cells, in a dose-dependent manner, while current amplitude was not affected. The inactivation of NaV1.5 is slower by a factor of 4, 7, and 35 in the presence of [AahII] at 75, 150, and 300 nM, respectively. The washout partially reversed the toxin effect on inactivation from 8.3 ± 0.9 ms to 5.2 ± 1.2 ms at 75 nM. We have also demonstrated that the highly neutralizing Nb10 can fully reverse the effect of AahII toxin on the channel inactivation kinetics even at the 1:1 M ratio. However, the 1:0.5 M ratio is not able to neutralize completely the AahII effect. Therefore, the application of Nb10 promotes a partial abolishment of AahII action. Bioinformatic analysis and prediction of NaV1.5-driven docking with AahII show that Ala39 and Arg62 of AahII play a crucial role to establish a stable interaction through H-bound interactions with Gln1615 and Lys1616 (S3–S4 extracellular loop) and Asp1553 (S1–S2 loop) from the voltage-sensing domain IV (VSD4) of NaV1.5, respectively. From this, we notice that AahII shares the same contact surface with Nb10. This strongly suggests that Nb10 dynamically replaces AahII toxin from its binding site on the NaV1.5 channel. At the physiopathological level, Nb10 completely neutralized the enhancement of breast cancer cell invasion induced by AahII. In summary, for the first time, we made an electrophysiological and structural characterization of the neutralization potent of Nb10 against the α-scorpion toxin AahII in a cellular model overexpressing NaV1.5 channels.
Collapse
Affiliation(s)
- Riadh Hmaidi
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
- Laboratory of Cellular and Molecular Physiology UR 4667, UFR of Sciences, University of Picardie Jules Verne, Amiens, France
| | - Ayoub Ksouri
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Rahma Benabderrazek
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
| | - Viviane Antonietti
- Infectious Agents, Resistance and Chemotherapy UR 4294, UFR of Pharmacy, University of Picardie Jules Verne, Amiens, France
| | - Pascal Sonnet
- Infectious Agents, Resistance and Chemotherapy UR 4294, UFR of Pharmacy, University of Picardie Jules Verne, Amiens, France
| | - Mathieu Gautier
- Laboratory of Cellular and Molecular Physiology UR 4667, UFR of Sciences, University of Picardie Jules Verne, Amiens, France
- *Correspondence: Mathieu Gautier, ; Balkiss Bouhaouala-Zahar, ; Halima Ouadid-Ahidouch,
| | - Balkiss Bouhaouala-Zahar
- Laboratory of Biomolecules, Venoms, and Theranostic Applications, Institut Pasteur Tunis, University of Tunis El Manar, Tunis, Tunisia
- Medical School of Tunis, University of Tunis El Manar, Tunis, Tunisia
- *Correspondence: Mathieu Gautier, ; Balkiss Bouhaouala-Zahar, ; Halima Ouadid-Ahidouch,
| | - Halima Ouadid-Ahidouch
- Laboratory of Cellular and Molecular Physiology UR 4667, UFR of Sciences, University of Picardie Jules Verne, Amiens, France
- *Correspondence: Mathieu Gautier, ; Balkiss Bouhaouala-Zahar, ; Halima Ouadid-Ahidouch,
| |
Collapse
|
2
|
Vaucel J, Mutricy R, Hoarau M, Pujo JM, Elenga N, Labadie M, Kallel H. Pediatric scorpionism in northern Amazonia: a 16-year study on epidemiological, environmental and clinical aspects. J Venom Anim Toxins Incl Trop Dis 2020; 26:e202000038. [PMID: 32973890 PMCID: PMC7485965 DOI: 10.1590/1678-9199-jvatitd-2020-0038] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Background: The Amazon basin is one of the seven major geographical areas where
scorpionism is recorded. In French Guiana, 90 stings per 100,000 inhabitants
are registered per year. As the severity of cases is higher in children,
descriptive studies are needed to have a better understanding of this
pathology. The aim of the present study is to describe pediatric scorpionism
in French Guiana. Methods: We conducted a monocentric descriptive retrospective study on scorpion
stings in all pediatric patients admitted to Cayenne General Hospital from
January 1, 2002 to December 31, 2018. Results: In this survey, 132 patients were included. Of them, 63% were male. Patients
with general signs of envenomation were younger and lighter (p = 0.04). The
picture was “one sting” (95.3%) by a “big” (47.6%), “black” (60%) and “small
pincer” (58%) scorpion on the extremity of the body (84%). Stings occurred
mainly during the day, while patients changed clothes. There was no
envenomation during night. The monthly evaluation highlights that the number
of stings and percentage of general signs of envenomation were closely
connected to a composite variable including the variation of the level of
rivers (p = 0.005). Cardiac symptoms were recorded in 82% of cases with
general signs of envenomation. The presence of pulmonary; ear, nose, and
throat (ENT); or gastrointestinal symptoms are related to major envenomation
(p = 0.001, p = 0.01, and p = 0.02 respectively). Leukocytosis and glycemia
increased according to the envenomation grade whereas serum potassium and
alkaline reserve decreased. Forty-six patients needed hospitalization and
seven of them required intensive care. No patient died nor presented
sequelae at discharge from the hospital. Conclusion: Pediatric scorpionism in French Guiana is closely associated with child
activities and climatic conditions. Severe envenomation presented most of
the time with cardiac, pulmonary, and gastrointestinal symptoms.
Collapse
Affiliation(s)
- Jules Vaucel
- Poison Control Center (Centre Antipoison) Nouvelle Aquitaine, Centre Hospitalier et Universitaire Pellegrin, Bordeaux 33076, Aquitaine, France.,Emergency Department, Centre Hospitalier de Cayenne, Cayenne 97300, French Guiana, France
| | - Remi Mutricy
- Emergency Department, Centre Hospitalier de Cayenne, Cayenne 97300, French Guiana, France
| | - Maëlle Hoarau
- Emergency Department, Centre Hospitalier de Cayenne, Cayenne 97300, French Guiana, France
| | - Jean-Marc Pujo
- Emergency Department, Centre Hospitalier de Cayenne, Cayenne 97300, French Guiana, France
| | - Narcisse Elenga
- Emergency Pediatric Department, Centre Hospitalier de Cayenne, Cayenne 97300, French Guiana, France
| | - Magali Labadie
- Poison Control Center (Centre Antipoison) Nouvelle Aquitaine, Centre Hospitalier et Universitaire Pellegrin, Bordeaux 33076, Aquitaine, France
| | - Hatem Kallel
- Intensive Care Unit, Centre Hospitalier de Cayenne, Cayenne 97300, French Guiana, France
| |
Collapse
|
3
|
Rebbouh F, Martin-Eauclaire MF, Laraba-Djebari F. Chitosan nanoparticles as a delivery platform for neurotoxin II from Androctonus australis hector scorpion venom: Assessment of toxicity and immunogenicity. Acta Trop 2020; 205:105353. [PMID: 31982432 DOI: 10.1016/j.actatropica.2020.105353] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/19/2020] [Accepted: 01/20/2020] [Indexed: 10/25/2022]
Abstract
In recent years, biodegradable polymers based nanoparticles received high interest for the development of vaccine delivery vehicles. In this study, chitosan nanoparticles encapsulating Aah II toxin (AahII-CNPs) isolated from Androctonus australis hector venom, were investigated as vaccine delivery system. Particles obtained by ionotropic gelation were characterized for their size, surface charge, morphology and toxin release profile from Aah II-CNPs. Toxin-nanoparticles interactions were assessed by Fourier Transform Infrared Spectrometry and X-Ray Diffraction. An immunization protocol was designed in mice to investigate anti-toxin immunity and the protective status induced by different Aah II immune formulations. Unloaded chitosan nanoparticles presenting a spherical shape and smooth surface, were characterized by a size of 185 nm, a dispersion index (PDI) of 0.257 and a zeta potential of +34.6 mV. Aah II toxin was successfully entrapped into chitosan nanoparticles as revealed by FTIR and XRD data. Entrapment efficiency (EE) and Loading capacity (LC) were respectively of 96.66 and 33.5%. Aah II-CNPs had a diameter of 208 nm, a PDI of 0.23 and a zeta potential of +30 mV. Encapsulation of Aah II reduced its toxicity and protected mice until 10 LD50. Mice were immunized via a dual prime-boost scheme. Nanoentrapped Aah II immunogen elicited systemic innate and humoral immune responses as well as local spleen parenchyma hyperplasic alterations. Aah II-CNPs immunized mice withstood high lethal doses of native Aah II, one-month post-boost inoculation. This study provided encouraging and promising results for the development of preventive therapies against scorpion envenoming mainly for the populations at-risk.
Collapse
|
4
|
Galíndez-Cerón JD, Jorge RJB, Chavez-Acosta MH, Jorge ARC, Alves NTQ, Prata MMG, Rodrigues FADP, Havt A, Sampaio TL, Martins AMC, Guerrero-Vargas JA, Monteiro HSA, Beltrán-Vidal JT. Renal Alterations Induced by the Venom of Colombian Scorpion Centruroides Margaritatus. Curr Top Med Chem 2019; 19:2049-2057. [PMID: 31364515 DOI: 10.2174/1568026619666190731143523] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 05/21/2019] [Accepted: 06/05/2019] [Indexed: 12/25/2022]
Abstract
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.
Collapse
Affiliation(s)
- J D Galíndez-Cerón
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
| | - R J B Jorge
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - M H Chavez-Acosta
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
| | - A R C Jorge
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - N T Q Alves
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - M M G Prata
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - F A de Paulo Rodrigues
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - A Havt
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - T L Sampaio
- Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - A M C Martins
- Departamento de Análises Clínicas e Toxicológicas, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - J A Guerrero-Vargas
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
| | - H S A Monteiro
- Departamento de Fisiologia e Farmacologia, Faculdade de Medicina, Universidade Federal do Ceará, Fortaleza, CE, Brazil
| | - J T Beltrán-Vidal
- Departamento de Biología, Facultad de Ciencias Naturales, Exactas y de la Educación, Grupo de Investigaciones Herpetológicas y Toxinológicas, Universidad del Cauca, Popayán, Colombia
| |
Collapse
|
5
|
Ksouri A, Ghedira K, Ben Abderrazek R, Shankar BG, Benkahla A, Bishop OT, Bouhaouala-Zahar B. Homology modeling and docking of AahII-Nanobody complexes reveal the epitope binding site on AahII scorpion toxin. Biochem Biophys Res Commun 2018; 496:1025-1032. [DOI: 10.1016/j.bbrc.2018.01.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 01/04/2018] [Indexed: 11/25/2022]
|
6
|
Emerich BL, De Lima ME, Martin-Eauclaire MF, Bougis PE. Comparative analyses and implications for antivenom serotherapy of four Moroccan scorpion Buthus occitanus venoms: Subspecies tunetanus, paris, malhommei, and mardochei. Toxicon 2017; 149:26-36. [PMID: 28712915 DOI: 10.1016/j.toxicon.2017.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 07/04/2017] [Accepted: 07/10/2017] [Indexed: 01/14/2023]
Abstract
Temporary passive immunity such as serotherapy against venoms requires the full knowledge of all venom's components. Here, four venoms from Moroccan common yellow scorpions belonging to Buthus occitanus, subspecies tunetanus, paris, malhommei, and mardochei, all collected in four different restricted areas, were analysed in deep. They were fractionated by reversed-phase high-performance liquid chromatography (RP-HPLC) and their molecular masse profile determined by off-line MALDI-TOF mass spectrometry. Characterisation of their main components was achieved by enzyme-linked immunosorbent assay (ELISA) using specific antisera against the major lethal scorpion toxins identified so far, i.e. voltage-gated sodium channels (Nav) modulators α- and β-toxins, as well as diverse potassium channel pore blocker toxins. For fractions with identical RP-HPLC retention times, we observe that their relative quantities show large differences. Moreover, identical masses present simultaneously in the four venoms are infrequent. ELISAs show that the majority of the RP-HPLC compounds cross-react with the antiserum against the "α-like" toxin Bot I, which has been previously identified in the Algerian Buthus occitanus tunetanus venom. Moreover, minor fractions were recognised by the antiserum against the highly lethal "classical" α-toxin of reference AaH II from the Androctonus australis venom. As such, our results bring new sights for further improving scorpion venom serotherapy in Morocco.
Collapse
Affiliation(s)
- Bruna Luiza Emerich
- Aix Marseille Université, CNRS, CRN2M UMR7286, 13344, Marseille, France; Laboratório de Venenos e Toxinas Animais, Dept de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo-Horizonte, MG, Brazil
| | - Maria Elena De Lima
- Laboratório de Venenos e Toxinas Animais, Dept de Bioquímica e Imunologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, 31270-901, Belo-Horizonte, MG, Brazil
| | | | - Pierre E Bougis
- Aix Marseille Université, CNRS, CRN2M UMR7286, 13344, Marseille, France.
| |
Collapse
|
7
|
Saidani C, Hammoudi-Triki D, Laraba-Djebari F, Taub M. In vitro studies with renal proximal tubule cells show direct cytotoxicity of Androctonus australis hector scorpion venom triggered by oxidative stress, caspase activation and apoptosis. Toxicon 2016; 120:29-37. [PMID: 27470530 DOI: 10.1016/j.toxicon.2016.07.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/13/2016] [Accepted: 07/20/2016] [Indexed: 01/20/2023]
Abstract
Scorpion envenomation injures a number of organs, including the kidney. Mechanisms proposed to explain the renal tubule injury include direct effects of venom on tubule epithelial cells, as well as indirect effects of the autonomic nervous system, and inflammation. Here, we report direct effects of Androctonus australis hector (Aah) scorpion venom on the viability of Renal Proximal Tubule (RPT) cells in vitro, unlike distal tubule and collecting duct cells. Extensive NucGreen nuclear staining was observed in immortalized rabbit RPT cells following treatment with Aah venom, consistent with cytotoxicity. The involvement of oxidative stress is supported by the observations that 1) anti-oxidants mitigated the Aah venom-induced decrease in the number of viable RPT cells, and 2) Aah venom-treated RPT cells were intensively stained with the CellROX(®) Deep Red reagent, an indicator of Reactive Oxygen Species (ROS). Relevance to normal RPT cells is supported by the red fluorescence observed in Aah venom treated primary rabbit RPT cell cultures following their incubation with the Flica reagent (indicative of caspase activation and apoptosis), and the green fluorescence of Sytox Green (indicative of dead cells).
Collapse
Affiliation(s)
- Chanez Saidani
- Université des Sciences et de la Technologie Hourari Boumediene (USTHB), Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, Department of Cellular and Molecular Biology, BP32, El Alia, Bab Ezzouar 16111, Algiers, Algeria
| | - Djelila Hammoudi-Triki
- Université des Sciences et de la Technologie Hourari Boumediene (USTHB), Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, Department of Cellular and Molecular Biology, BP32, El Alia, Bab Ezzouar 16111, Algiers, Algeria
| | - Fatima Laraba-Djebari
- Université des Sciences et de la Technologie Hourari Boumediene (USTHB), Faculty of Biological Sciences, Laboratory of Cellular and Molecular Biology, Department of Cellular and Molecular Biology, BP32, El Alia, Bab Ezzouar 16111, Algiers, Algeria
| | - Mary Taub
- Biochemistry Department, School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY, USA.
| |
Collapse
|
8
|
Ladjel-Mendil A, Martin-Eauclaire MF, Laraba-Djebari F. Neuro-Modulation of Immuno-Endocrine Response Induced by Kaliotoxin of Androctonus Scorpion Venom. J Biochem Mol Toxicol 2016; 30:580-587. [PMID: 27271987 DOI: 10.1002/jbt.21824] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 05/18/2016] [Accepted: 05/23/2016] [Indexed: 12/16/2022]
Abstract
Kaliotoxin (KTX), a specific blocker of potassium channels, exerts various toxic effects due to its action on the central nervous system. Its use in experimental model could help the understanding of the cellular and molecular mechanisms involved in the neuropathological processes related to potassium channel dysfunctions. In this study, the ability of KTX to stimulate neuro-immuno-endocrine axis was investigated. As results, the intracerebroventricular injection of KTX leads to severe structural-functional alterations of both hypothalamus and thyroid. These alterations were characterized by a massive release of hormones' markers of thyroid function associated with damaged tissue which was infiltrated by inflammatory cell and an imbalanced redox status. Taken together, these data highlight that KTX is able to modulate the neuro-endocrine response after binding to its targets leading to the hypothalamus and the thyroid stimulation, probably by inflammatory response activation and the installation of oxidative stress in these organs.
Collapse
Affiliation(s)
- Amina Ladjel-Mendil
- USTHB, Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, University of Sciences and Technology Houari Boumediene, Algiers, Algeria
| | - Marie-France Martin-Eauclaire
- CNRS UMR 7286 CRN2M, Institut Fédératif de Recherche Jean Roche, Faculté de Médecine Nord, Aix-Marseille University, Marseille, France
| | - Fatima Laraba-Djebari
- USTHB, Laboratory of Cellular and Molecular Biology, Faculty of Biological Sciences, University of Sciences and Technology Houari Boumediene, Algiers, Algeria
| |
Collapse
|
9
|
Medjadba W, Martin-Eauclaire MF, Laraba-Djebari F. Involvement of Kallikrein-Kinin System on Cardiopulmonary Alterations and Inflammatory Response Induced by Purified Aah I Toxin from Scorpion Venom. Inflammation 2015; 39:290-302. [PMID: 26361946 DOI: 10.1007/s10753-015-0249-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Bradykinins are released from kininogen by kallikrein. They increase capillary lung permeability after their binding to β1 and especially β2 receptors before being metabolized by kininase enzyme. This study was performed to evaluate cardiopulmonary damages and inflammatory response on injected rats with Aah I toxin of scorpion venom and the involvement of Kallikrein-Kinin system in this pathogenesis. Obtained results revealed that Aah I toxin induces inflammatory cell infiltration accompanied by cellular peroxidase activities, a release of cytokine levels, pulmonary and myocardial damage, with altered metabolic activities and imbalanced redox status. Administration of aprotinin (bradykinin inhibitor) and especially icatibant (bradykinin β2 receptor antagonist) seemed to be able to protect animals against the toxicity of Aah I; nevertheless, the use of captopril (kininase II inhibitor) reduced partially some cardiac disorders. These findings indicate that the kallikrein-kinin system may contribute to the physiopathological effect and lung edema formation induced by toxin, which suggests a potential use of drugs with significant anti-kinin properties.
Collapse
Affiliation(s)
- Wafa Medjadba
- USTHB, Faculty of Biological Sciences, Laboratory Cellular and Molecular Biology, Department Cellular and Molecular Biology, BP32, EL Alia, Bab Ezzouar, 16111, Algiers, Algeria
| | - Marie-France Martin-Eauclaire
- Aix-Marseille University, CNRS UMR 7286 CRN2M, IFR Jean-Roche, Faculté de Médecine Nord, Bd Pierre Dramard, 13916, Marseille, Cedex 20, France
| | - Fatima Laraba-Djebari
- USTHB, Faculty of Biological Sciences, Laboratory Cellular and Molecular Biology, Department Cellular and Molecular Biology, BP32, EL Alia, Bab Ezzouar, 16111, Algiers, Algeria.
| |
Collapse
|
10
|
|
11
|
van der Valk T, van der Meijden A. Toxicity of scorpion venom in chick embryo and mealworm assay depending on the use of the soluble fraction versus the whole venom. Toxicon 2014; 88:38-43. [DOI: 10.1016/j.toxicon.2014.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 06/05/2014] [Accepted: 06/11/2014] [Indexed: 12/23/2022]
|
12
|
Alvarenga LM, Zahid M, di Tommaso A, Juste MO, Aubrey N, Billiald P, Muzard J. Engineering venom's toxin-neutralizing antibody fragments and its therapeutic potential. Toxins (Basel) 2014; 6:2541-67. [PMID: 25153256 DOI: 10.3390/toxins6082541] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/16/2014] [Accepted: 08/04/2014] [Indexed: 11/24/2022] Open
Abstract
Serum therapy remains the only specific treatment against envenoming, but anti-venoms are still prepared by fragmentation of polyclonal antibodies isolated from hyper-immunized horse serum. Most of these anti-venoms are considered to be efficient, but their production is tedious, and their use may be associated with adverse effects. Recombinant antibodies and smaller functional units are now emerging as credible alternatives and constitute a source of still unexploited biomolecules capable of neutralizing venoms. This review will be a walk through the technologies that have recently been applied leading to novel antibody formats with better properties in terms of homogeneity, specific activity and possible safety.
Collapse
|
13
|
Gad W, Ben-Abderrazek R, Wahni K, Vertommen D, Muyldermans S, Bouhaouala-Zahar B, Messens J. Wheat germ in vitro translation to produce one of the most toxic sodium channel specific toxins. Biosci Rep 2014; 34:e00122. [PMID: 24924257 DOI: 10.1042/BSR20140050] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Envenoming following scorpion sting is a common emergency in many parts of the world. During scorpion envenoming, highly toxic small polypeptides of the venom diffuse rapidly within the victim causing serious medical problems. The exploration of toxin structure-function relationship would benefit from the generation of soluble recombinant scorpion toxins in Escherichia coli. We developed an in vitro wheat germ translation system for the expression of the highly toxic Aah (Androctonus australis hector)II protein that requires the proper formation of four disulphide bonds. Soluble, recombinant N-terminal GST (glutathione S-transferase)-tagged AahII toxin is obtained in this in vitro translation system. After proteolytic removal of the GST-tag, purified rAahII (recombinant AahII) toxin, which contains two extra amino acids at its N terminal relative to the native AahII, is highly toxic after i.c.v. (intracerebroventricular) injection in Swiss mice. An LD50 (median lethal dose)-value of 10 ng (or 1.33 pmol), close to that of the native toxin (LD50 of 3 ng) indicates that the wheat germ in vitro translation system produces properly folded and biological active rAahII. In addition, NbAahII10 (Androctonus australis hector nanobody 10), a camel single domain antibody fragment, raised against the native AahII toxin, recognizes its cognate conformational epitope on the recombinant toxin and neutralizes the toxicity of purified rAahII upon injection in mice. A wheat germ embryo derived cell-free translation system expresses a biologically active, highly toxic scorpion venom protein that is fully neutralized by a camel single domain antibody fragment raised against the native scorpion toxin.
Collapse
|
14
|
Coelho P, Sousa P, Harris D, van der Meijden A. Deep intraspecific divergences in the medically relevant fat-tailed scorpions (Androctonus, Scorpiones). Acta Trop 2014; 134:43-51. [PMID: 24524948 DOI: 10.1016/j.actatropica.2014.02.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/28/2014] [Accepted: 02/01/2014] [Indexed: 10/25/2022]
Abstract
The genus Androctonus, commonly known as fat-tailed scorpions, contains 22 species distributed from Togo and Mauritania in the west, North Africa, through the Middle East and to as far east as India. With 13 species, a substantial amount of this genus' diversity occurs in North Africa, which is a major hotspot of scorpion sting incidents. Androctonus are among the most medically relevant animals in North Africa. Since venom composition within species is known to vary regionally, the improvement of therapeutic management depends on a correct assessment of the existing regional specific and sub-specific variation. In this study, we assessed the phylogeographical patterns in six species of Androctonus scorpions from North Africa using mitochondrial DNA markers. We sequenced COX1, 12S, 16S and ND1 genes from 110 individuals. Despite lacking basal resolution in the tree, we found taxonomical and geographically coherent clades. We discovered deep intraspecific variation in the widespread Androctonus amoreuxi and Androctonus australis, which consisted of several well-supported clades. Genetic distances between some of these clades are as high as those found between species. North African A. australis have a deep split in Tunisia around the Chott el-Djerid salt-lake. A novel split between A. amoreuxi scorpions was found in Morocco. We also found deep divergences in Androctonus mauritanicus, corresponding to areas attributed to invalidated subspecies. In addition we uncovered a clade of specimens from coastal south Morocco, which could not be ascribed to any know species using morphological characters. Based on these findings we recommend a reassessment of venom potency and anti-venom efficacy between these deep intraspecific divergent clades.
Collapse
|
15
|
Aboumaâd B, Iba N, Dersi N. L’envenimation scorpionique au Maroc : scorpions du genre Androctonus, Buthus et Hottentota. ACTA ACUST UNITED AC 2014; 107:39-47. [DOI: 10.1007/s13149-014-0332-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 12/17/2013] [Indexed: 11/25/2022]
|
16
|
Kassiri H, Kassiri E, Veys-Behbahani R, Kassiri A. Epidemiological survey on scorpionism in Gotvand County, Southwestern Iran: an analysis of 1 067 patients. Journal of Acute Disease 2014. [DOI: 10.1016/s2221-6189(14)60067-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
|
17
|
Martin-Eauclaire MF, Granjeaud S, Belghazi M, Bougis PE. Achieving automated scorpion venom mass fingerprinting (VMF) in the nanogram range. Toxicon 2013; 69:211-8. [DOI: 10.1016/j.toxicon.2013.03.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Revised: 02/11/2013] [Accepted: 03/01/2013] [Indexed: 10/27/2022]
|
18
|
Hmila I, Cosyns B, Tounsi H, Roosens B, Caveliers V, Abderrazek RB, Boubaker S, Muyldermans S, El Ayeb M, Bouhaouala-Zahar B, Lahoutte T. Pre-clinical studies of toxin-specific Nanobodies: Evidence of in vivo efficacy to prevent fatal disturbances provoked by scorpion envenoming. Toxicol Appl Pharmacol 2012; 264:222-31. [DOI: 10.1016/j.taap.2012.07.033] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2012] [Revised: 06/30/2012] [Accepted: 07/30/2012] [Indexed: 11/15/2022]
|
19
|
di Tommaso A, Juste MO, Martin-Eauclaire MF, Dimier-Poisson I, Billiald P, Aubrey N. Diabody mixture providing full protection against experimental scorpion envenoming with crude Androctonus australis venom. J Biol Chem 2012; 287:14149-56. [PMID: 22375011 PMCID: PMC3340170 DOI: 10.1074/jbc.m112.348912] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Indexed: 01/24/2023] Open
Abstract
Androctonus australis is primarily involved in envenomations in North Africa, notably in Tunisia and Algeria, and constitutes a significant public health problem in this region. The toxicity of the venom is mainly due to various neurotoxins that belong to two distinct structural and immunological groups, group I (the AahI and AahIII toxins) and group II (AahII). Here, we report the use of a diabody mixture in which the molar ratio matches the characteristics of toxins and polymorphism of the venom. The mixture consists of the Db9C2 diabody (anti-group I) and the Db4C1op diabody (anti-AahII), the latter being modified to facilitate in vitro production and purification. The effectiveness of the antivenom was tested in vivo under conditions simulating scorpion envenomation. The intraperitoneal injection of 30 μg of the diabody mixture protected almost all the mice exposed to 3 LD(50) s.c. of venom. We also show that the presence of both diabodies is necessary for the animals to survive. Our results are the first demonstration of the strong protective power of small quantities of antivenom used in the context of severe envenomation with crude venom.
Collapse
Affiliation(s)
- Anne di Tommaso
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
| | - Matthieu O. Juste
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
| | | | - Isabelle Dimier-Poisson
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
| | | | - Nicolas Aubrey
- From the Université de Tours, UMR1282 Infectiologie et Santé Publique, 37200 Tours
- Institut National de la Recherche Agronomique, UMR1282 Infectiologie et Santé Publique, 37380 Nouzilly
| |
Collapse
|
20
|
Raouraoua-Boukari R, Sami-Merah S, Hammoudi-Triki D, Martin-Eauclaire MF, Laraba-Djebari F. Immunomodulation of the inflammatory response induced by Androctonus australis hector neurotoxins: biomarker interactions. Neuroimmunomodulation 2012; 19:103-10. [PMID: 22248726 DOI: 10.1159/000330241] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 06/03/2011] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE Androctonus australis hector (Aah) is the most dangerous scorpion in the Maghreb countries. Its venom contains three major neurotoxins (Aah I, Aah II and Aah III), which are responsible for almost all the lethal effects caused in mammals. These toxins act on the voltage-gated sodium channels of excitable cells. The targets and the lethal effects of these toxins have been extensively studied. However, their effects on the induced immune response after envenoming have not deeply elicited. We therefore investigated the effects induced by Aah venom and its toxic components, mainly its main toxin Aah II, on the activation of the inflammatory process. METHODS Wistar rats were injected by intraperitoneal route with a sublethal dose of Aah venom, FTox-G50, the purified Aah II toxin or with 400 μl of sterile physiological saline solution. Immunological biomarkers such as MPO, NO and ICAM-1 were analyzed in serum in lung tissue. Cytokine levels were also determined in serum at 3, 6 and 24 h after envenoming. RESULTS We report in this study that intraperitoneal injection of the venom or its toxins (the whole toxic fraction or Aah II toxin) caused an inflammatory reaction involving increased neutrophil release into blood and neutrophil accumulation in lung tissue. This cell infiltration was associated with the release of NO, histamine, cytokines (IL-1, IL-6, IL-12, IL-4 and IL-5) and ICAM. CONCLUSION Aah II binding to its targets, in this case Na⁺ channels, may induce a cascade of events such as inflammatory mediator release and neutrophil migration that could contribute to the exacerbation of the systemic inflammatory response and the development of lung injury following scorpion envenoming.
Collapse
Affiliation(s)
- Ryma Raouraoua-Boukari
- Laboratoire de Biologie Cellulaire et Moléculaire, Faculté des Sciences Biologiques, Université des Sciences et de la Technologie «Houari Boumédienne», Alger, Algérie
| | | | | | | | | |
Collapse
|
21
|
Abderrazek RB, Hmila I, Vincke C, Benlasfar Z, Pellis M, Dabbek H, Saerens D, El Ayeb M, Muyldermans S, Bouhaouala-Zahar B. Identification of potent nanobodies to neutralize the most poisonous polypeptide from scorpion venom. Biochem J 2009; 424:263-72. [PMID: 19732033 DOI: 10.1042/BJ20090697] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Scorpion venom, containing highly toxic, small polypeptides that diffuse rapidly within the patient, causes serious medical problems. Nanobodies, single-domain antigen-binding fragments derived from dromedary heavy-chain antibodies, have a size that closely matches that of scorpion toxins. Therefore these nanobodies might be developed into potent immunotherapeutics to treat scorpion envenoming. Multiple nanobodies of sub-nanomolar affinity to AahII, the most toxic polypeptide within the Androctonus australis hector venom, were isolated from a dromedary immunized with AahII. These nanobodies neutralize the lethal effect of AahII to various extents without clear correlation with the kinetic rate constants kon or koff, or the equilibrium dissociation constant, KD. One particular nanobody, referred to as NbAahII10, which targets a unique epitope on AahII, neutralizes 7 LD50 of this toxin in mice, corresponding to a neutralizing capacity of approx. 37000 LD50 of AahII/mg of nanobody. Such high neutralizing potency has never been reached before by any other monoclonal antibody fragment.
Collapse
|
22
|
Nasr HB, Bolon B, Hammami ST, Sahnoun Z, Jamoussi K, Lahyani A, Zeghal KM. Clinical pathology alterations in pregnant and non-pregnant rats following scorpion envenomation. Basic Clin Pharmacol Toxicol 2009; 105:228-35. [PMID: 19663823 DOI: 10.1111/j.1742-7843.2009.00430.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Scorpion envenomation is a growing problem in many countries, especially among women and children. Existing diagnostic criteria are not sufficiently specific to allow antivenin administration in the absence of a confirmed scorpion sting. This study was performed to evaluate conventional haematological and serum chemical measurements as potential indices of scorpion envenomation. Adult, cycling nulliparous and near-term primiparous, white Wistar rats received a single subcutaneous injection of crude venom (600 µg/kg) from the Buthidae scorpion (Buthus occitanus tunetanus). All envenomed rats were observed for external signs and symptoms of toxicity until necropsy, which entailed terminal blood collection at either 0.5, 1, 2, or 4 hr after venom administration (n = 6 per reproductive state per time-point) for evaluation of selected clinical chemistry and haematological analytes. Control cohorts (matched for age and reproductive state) received saline injections subcutaneously and were necropsied at 0.5 hr. Almost all envenomed rats but no control animals displayed physical symptoms of intoxication, including agitation, mastication with hypersalivation, and/or vocalizing. Reproducible alterations in clinical pathology parameters were lacking in venom-treated rats regardless of reproductive status, although modest but significant Rho correlations suggested that mild haemoconcentration, haemolysis, renal function deficits and possibly coagulation difficulties developed over time.
Collapse
Affiliation(s)
- Hmed Ben Nasr
- Laboratory of Pharmacology, Medical School of Sfax, Sfax, Tunisia.
| | | | | | | | | | | | | |
Collapse
|
23
|
Charrab N, Soulaymani Bencheikh R, Mokhtari A, Semlali I, El Oufir R, Soulaymani A. Situation épidémiologique des envenimations scorpioniques dans la province de Beni Mellal. Santé Publique 2009. [DOI: 10.3917/spub.094.0393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
24
|
Abstract
The scorpionism is an actual public health problem in several parts of the world because, either incidence, or severity of envenomations is high and managed with difficulty by health services, or for these two reasons at the same time. The treatment of scorpion envenomation is complex and controversial, in particular regarding the utility of the antivenoms and symptomatic treatments that must be associated. The authors reviewed the literature of last 30 years to discuss the epidemiologic importance of scorpionism and to point out the principal therapeutic or preventive measures. According to the most recent studies, seven areas were identified as at risk: north-Saharan Africa, Sahelian Africa, South Africa, Near and Middle-East, South India, Mexico and South Latin America, east of the Andes. These involve 2.3 billion at risk population. The annual number of scorpion stings exceeds 1.2 million leading to more than 3250 deaths (0.27%). Although adults are more often concerned, children experience more severe envenomations and among them, mortality is higher. Improvement of therapeutic management would reduce the lethality very significantly.
Collapse
|
25
|
El-Alfy AT, Ahmed AA, Fatani AJ, Kader F. Amelioration of the cardiovascular manifestations of the yellow scorpion Leiurus quinquestriatus envenomation in rats by red grape seeds proanthocyanidins. Toxicon 2008; 51:321-33. [DOI: 10.1016/j.toxicon.2007.07.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2007] [Revised: 07/02/2007] [Accepted: 07/03/2007] [Indexed: 10/23/2022]
|
26
|
Ben Nasr H, Hammami S, Mion G, Sahnoun Z, Chouaiekh F, Rebaï T, Kassis M, Goyffon M, Zeghal K. [Effects of Buthus occitanus tunetanus envenomation on an experimental murine model of gestation]. C R Biol 2007; 330:890-6. [PMID: 18068647 DOI: 10.1016/j.crvi.2007.09.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 09/03/2007] [Accepted: 09/05/2007] [Indexed: 11/23/2022]
Abstract
Scorpion envenoming is less studied in pregnant victims. In this work, the effect of Buthus occitanus tunetanus on parturition in late pregnancy was studied in an animal model. Four groups of six primigravid female rats, each one at the 22nd day of pregnancy, were used. The first two groups had received an intra-peritoneal injection of 500 microg/kg of Buthus occitanus tunetanus crude venom or a physiological saline solution and left until foetal delivery. Then, the time elapsed until the first pup delivery and that separating the first and latest ones were measured. The other two groups served for the uterine electrophysiological activity exploration. Rats were anaesthetized, artificially ventilated and had received an intraperitoneal injection of 500 microg/kg of Buthus occitanus tunetanus crude venom or a physiological saline solution. Our results showed a significant increase of the latency to foetal delivery, labour time, and uterine contractile activity in envenomed rats compared to controls. Such signs are usually seen in dynamic dystocia. It was concluded that Buthus occitanus tunetanus envenoming might induce a dynamic dystocia, when it occurred in late pregnancy.
Collapse
|
27
|
Dousset E, Carrega L, Steinberg JG, Clot-Faybesse O, Jouirou B, Sauze N, Devaux C, Autier Y, Jammes Y, Martin-Eauclaire MF, Guieu R. Evidence that free radical generation occurs during scorpion envenomation. Comp Biochem Physiol C Toxicol Pharmacol 2005; 140:221-6. [PMID: 15907767 DOI: 10.1016/j.cca.2005.02.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2004] [Revised: 02/07/2005] [Accepted: 02/07/2005] [Indexed: 10/25/2022]
Abstract
Although it is well established that symptomatology, morbidity and death following scorpion envenomation are due to increases in neurotransmitter release secondary to toxins binding to voltage-sensitive sodium channels, the mechanism by which venom action is involved in damaging heart, liver, lungs and kidneys remains unclear. We hypothesized that scorpion toxins could induce the generation of high levels of free radicals responsible for membrane damage in organs targeted by venom action. We have investigated lipid peroxidation in different organs, through the evaluation of thiobarbituric acid reactive substances (TBARS), after experimental envenomation of rats by toxic fractions of Androctonus australis Hector venom. We have shown that scorpion toxins cause considerable lipid peroxidation in most vital organs. We also evaluated the protective effects of antioxidants in mice injected with lethal doses of toxins. Among the drugs tested, N-acetylcysteine (NAC) was effective in protecting the mice when injected prior to toxin application. However, the free radical scavenging properties of NAC seem less implicated in these protective effects than its ability to increase the fluidity of bronchial secretions. We therefore conclude that free radical generation only plays a minor role in the toxicity of scorpion venom.
Collapse
Affiliation(s)
- E Dousset
- Laboratoire des Déterminants Physiologiques de l'Activité Physique (UPRES EA 3285), Institut Fédératif de Recherche E-J Marey (IFR 107), Faculté des Sciences du Sport, Université de la Méditerranée (Aix-Marseille II), Marseille, France
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|