Cardiorespiratory alterations in rodents experimentally envenomed with Hadruroides lunatus scorpion venom

Abstract Background Hadruroides lunatus is the most abundant scorpion species in the Peruvian central coast, where most of the accidents involving humans are registered. In spite of its prevalence, there are only very few studies on H. lunatus envenomation. The aim of the present study was to analyze the cardiorespiratory alterations caused by H. lunatus envenomation in rodents. Methods Wistar rats injected with H. lunatus scorpion venom were submitted to electrocardiography. After euthanasia, rat lungs were collected and histopathologically analyzed. Mouse cardiomyocytes were used to perform immunofluorescence and calcium transient assays. Data were analyzed by ANOVA or Student’s t-test. The significance level was set at p< 0.05. Results It was observed that H. lunatus venom increased heart rate and caused arrhythmia, thereby impairing the heart functioning. Lungs of envenomed animals showed significant alterations, such as diffuse hemorrhage. In addition, immunofluorescence showed that H. lunatus venom was capable of binding to cardiomyocytes. Furthermore, mouse ventricular cardiomyocytes incubated with H. lunatus venom showed a significant decrease in calcium transient, confirming that H. lunatus venom exerts a toxic effect on heart. Conclusion Our results showed that H. lunatus venom is capable of inducing cardiorespiratory alterations, a typical systemic effect of scorpionism, stressing the importance of medical monitoring in envenomation cases.

Construction of three different recombinant scorpion fusion proteins with bifunctional activity.

This is the first report of three different fusion proteins with an antitumor-analgesic peptide obtained from Chinese scorpion Buthus martensii Karsch (BmKAGAP). The fusion proteins were constructed in the form of chimeric toxins, aiming to obtain bifunctional analgesic and antitumor activity. The fusion proteins consisted of luteinizing hormone-releasing hormone (LHRH), three different types of flexible linkers (L1, Ser-Ser-His-His-His-His-His-His-Ser-Ser-Gly-Leu-Val-Pro-Arg-Gly-Ser-His-Met; L2, Gly-Gly-Gly-Ser-Gly-Gly-Gly-Ser; L3, Ser-Gly-Gly-Ser-Gly-Gly-Ser-Gly-Gly-Gly-Ser-Ser-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Ser-Gly-Gly-Gly-Gly-Ser), and BmKAGAP. The genes coding three fusion proteins were cloned and expressed in E. coli in soluble form. Following two successive column chromatographic separations, purified fusion proteins were obtained. These fusion proteins exhibited analgesic activity in mice and were cytotoxic to a hepatocellular carcinoma cell line Hep3B.

Hematological and biochemical profiles of rats submitted to experimental poisoning with Tityus serrulatus venom / Perfis hematológicos de ratos submetidos ao envenenamento escorpiônico experimental por Tityus serrulatus

The hematological and biochemical profiles of newly weaned rats submitted to experimental poisoning with T. serrulatus venom were evaluated. Fifteen recently weaned male Wistar rats (mean weight 130g) were distributed into three equal groups (n = 5). Animals in the control group (group A) received a subcutaneous injection of 400μL of ultra-pure water, while those in the experimental groups received, by identical route, 400μL of a solution containing 100μg (group B) or 450μg (group C) of scorpion venom dissolved in ultra-pure water. Red blood cells indexes, and differential leukocyte and total platelet counts were determined, together with levels of serum glucose, urea, creatinine, lactic dehydrogenase, aspartate aminotransferase, amylase, insulin, and cortisol. No significant differences between the control and experimental groups regarding red blood cells indexes were found. In contrast, significant increases (P<0.05) in neutrophils, lymphocytes, and monocytes were observed in animals from groups B and C compared with the control group, while the number of platelets decreased. Serum glucose concentration remained unchanged in all groups, but important alterations were observed in the values of urea and creatinine. The results show that scorpion venom was detrimental to renal function as demonstrated by the altered urea and creatinine levels. Pancreatic function was also impaired, as revealed by the increase in amylase activity and the reduction in insulin levels.

Avaliaram-se os perfis hematológico e bioquímico de ratos recém-desmamados submetidos ao envenenamento experimental com veneno de Tityus serrulatus. Quinze ratos Wistar machos, média de peso de 130g, foram distribuídos aleatoriamente em três grupos (n = 5). Os animais do grupo-controle A foram inoculados com 400μL de água ultrapura, os do grupo experimental B receberam 400μL de uma solução contendo 100μg de veneno e os do grupo experimental C receberam 400μL de uma solução contendo 450μg de veneno. Foram determinados os índices da série vermelha, a contagem total e diferencial dos leucócitos e a contagem total de plaquetas, bem como os níveis da desidrogenase lática, aspartato aminotransferase, amilase, glicose, ureia, creatinina, cortisol e insulina. Não houve diferenças significativas entre o grupo-controle e os experimentais com relação aos índices da série vermelha. Foram observados aumentos significativos (P<0,05) no número de neutrófilos, linfócitos e monócitos nos ratos dos grupos B e C, enquanto o número de plaquetas diminuiu. A concentração de glicose permaneceu inalterada em todos os grupos, mas foram observadas importantes alterações nos valores séricos de ureia e creatinina. Esses resultados mostraram que o veneno de escorpião comprometeu o funcionamento dos rins. Como demonstrado pelo aumento da atividade da amilase sérica e a redução dos níveis de insulina, a função pancreática também foi afetada.

Escorpionismo em crianças e adolescentes: aspectos clínicos e epidemiológicos de pacientes hospitalizados / Scorpion poisoning among children and adolescents: clinical and epidemiological characteristics of hospitalized patients

Foram identificados 325 prontuários de crianças e adolescentes vítimas de picadas de escorpião (14,8 por cento de casos leves, 55,4 por cento de casos moderados e 29,8 por cento de casos graves). As variáveis associadas com maior gravidade foram: ausência de dor no local da picada, relato de sonolência à admissão e intervalo maior que três horas entre o acidente e o atendimento hospitalar.

Medical records relating to 325 children and adolescents who suffered scorpion stings were identified (14.8 percent were mild cases, 55.4 percent were moderate cases and 29.8 percent were severe cases). The variables associated with greater severity were: lack of pain at the sting location, sleepiness reported at hospital admission and a time interval greater than three hours between the accident and hospital attendance.

Cambios en aminoácidos luego de administración intraperitoneal de veneno del escorpión Tityus zulianus en ratones: Estudio con microdiálisis subcutánea y electroforesis capilar

Resumen. El envenenamiento por escorpiones es un problema de salud pública en la zona suroccidental de Venezuela. El Tityus zulianus es uno de los escorpiones que causa, especialmente en niños, edema pulmonar e insuficiencia cardíaca que pueden ser fatales y que se han atribuido en parte a una gran descarga simpática. La administración intraperitoneal de (20 µg/g peso) de veneno del T. zulianus a ratones anestesiados durante microdiálisis subcutánea provocó aumento de secreciones, dificultad respiratoria, convulsiones y muerte entre 30 min a 2 h. En los dializados recolectados antes y después de recibir el veneno, se analizaron 7 aminoácidos por electroforesis capilar con detección mediante fluorescencia inducida por láser (EC-DFIL). Se encontró un aumento en arginina (39%), fenilalanina (40%) y glutamato (94%), sin cambios en valina, serina y aspartato, en los animales que recibieron veneno con respecto a sus valores pretratamiento. Estos cambios porcentuales fueron significativos al comparar veneno vs. vehículo después de la inyección; y antes vs. después de recibir el veneno. Para este momento no hay una explicación clara del significado de estos aumentos de aminoácidos específicos. Se requieren nuevos estudios para conocer si estos cambios bioquímicos tienen o no una relación con los mecanismos de acción molecular del veneno o algunos de sus componentes y/o con las manifestaciones clínicas. De acuerdo con la literatura revisada, este es el primer reporte de la combinación de microdiálisis subcutánea y EC-DFIL en el estudio in vivo del emponzoñamiento por escorpiones en ratones.

Abstract. Scorpion human envenoming is a public health hazard in the southwest of Venezuela. Tityus zulianus is one of the scorpion species whose venom causes lung edema and cardiac failure in children. These occasionally deadly manifestations have been attributed to a massive sympathetic discharge. The intraperitoneal administration of T. zulianus venom (20 µg/g mouse) to anesthetized mice during subcutaneous microdialysis caused increased secretions, dyspnea, seizures and death between 30 min to 2 h. Seven amino acids were analyzed by capillary electrophoresis with laser induced fluorescence detection (CE-LIFD) in the collected samples before and after the venom administration. We found an increase of arginine (39%), phenylalanine (40%) and glutamate (94%), with no changes in valine, serine and aspartate, changes were significant when the injection of venom and vehicle were compared and before vs after venom injection. Further investigation is needed to know if the observed changes could be related to the molecular mechanisms of the venom or some of its components and therefore with the envenoming symptoms. To our knowledge, this is the first report with subcutaneous microdialysis and CE-LIFD coupling in scorpion envenomation studies in vivo, in mice.

Histopathological changes in albino mouse testis induced by the administration of Tityus n. sp. venom

Scorpion envenoming is a public health concern in northeastern Venezuela. Specimens of the genus Tityus are responsible for most of these. In experimental animals, Tityus venom produces histopathological changes in the skeletal muscle and pancreas, but its toxicity to the reproductive system has not been studied. The aim of this work is to describe the histopathological changes in testis and epididymis of albino mice induced by the administration of Tityus n. sp. venom. Sub-lethal doses of venom (3.75 mg/g mouse) were administered intramuscularly (IM) daily for 4 days. On the fifth day, the animals were sacrificed and the testes and epididymes were quickly removed and processed for light microscopy. The venom induced alterations in spermatogenesis. Sertoli cell vacuolation, immature germ cell shedding, spermatocyte arrest, and low sperm volume were observed in seminiferous tubules. Leydig cells were hardly affected. Vascular dilation and congestion were detected in the interstitital tissue. Immature germ cells were found in epididymal tubule lumina, but no abnormalities were observed in epididymal epithelial dells. These results show that Tityus n. sp. venom causes changes in mouse seminiferous epithelium, probably due to indirect action through the Sertoli cell.

Indian red scorpion venom modulates spontaneous activity of rat right atria through the involvement of cholinergic and adrenergic systems.

The effect of Indian red scorpion (Mesobuthus tamulus concanesis, Pocock; MBT) venom was investigated on isolated rat right atrial preparations. MBT venom (0.001-3.0 micrograms/ml) exhibited a peculiar concentration-response pattern with respect to rate. The venom concentrations between 0.001-0.01 microgram/ml increased the atrial rate (phase I), followed by a relative decrease with 0.03-0.3 microgram/ml (phase II), and then an abrupt increase with 0.6-3.0 micrograms/ml (phase III). On the other hand, the force was unaltered by venom at phases I and II, while an increase was seen at phase III (3.0 micrograms/ml). Propranolol (0.1 microM) completely blocked the cardiostimulant action of venom at phase III. Further, this stimulant action of venom was absent in atria obtained from reserpinized animals. Pretreatment with atropine (0.3 microM), produced tachycardia at concentrations 0.1-0.3 microgram/ml of venom. But, hexamethonium (30 microM) had no influence on the venom (0.1 microgram/ml)-induced alterations in rate. However, MBT venom increased the acetylcholinesterase (AChE) activity (2-3 fold) in a concentration-dependent manner. Tetrodotoxin (2 microM), did not block the increase in rate produced by 0.01 microgram/ml of venom. Results suggest that, MBT venom-induced alterations of cardiac rhythmicity are mediated through cholinergic as well as adrenergic mechanisms depending upon the concentrations. The modulation of atrial rate at very low concentrations may be due to the direct action of venom on the atrium.

Effect of Indian red scorpion (Mesobuthus tamulus concanesis, Pocock) venom on thyroxine and triiodothyronine in experimental acute myocarditis and its reversal by species specific antivenom.

Acute myocarditis was induced in dogs and rabbits by injection of scorpion (M. tamulus concanesis, earlier called Buthus tamulus) venom by s.c., i.m. or i.v. routes. A decrease in thyroxine (T4) levels was observed following i.v. injection of venom in dogs. In rabbits the venom (i.m.) did not elicit any change in T4 levels. Envenomation (s.c.) resulted in a reduction in triiodothyronine (T3) levels in dogs. Venom injection (s.c.) along with i.v. administration of the species specific antivenom (AScVS) did not cause any change in T3 and T4 levels in general. However an increase in T3 levels following AScVS was observed in envenomated dogs. The results suggest that scorpion envenomation caused an autonomic storm releasing massive amounts of catecholamines, angiotensin II, suppressed insulin secretion and reduced circulating T4 and T3 levels. Decrease in thyroid hormones results in fall in body temperature. Changes in the body temperature may increase the sensitivity of the scorpion venom and influence the course of toxicity.

Efectos del veneno de Buthus eupeus sobre la secreción gástrica / Effects of Buthus eupeus venom upon gastric secretion

La administración endovenosa del veneno del escorpión B. eupeus (a dosis de 0.25 mg/Kg) incrementa la secreción gastrica de acido y pepsinógeno en la rata, sin influenciar el volumen secretado. Ambas secreciones de acido y pepsinógeno fueron inhibidas por la atropina y la vagotomia. La secreción gastrica de ácido fue incrementada por el veneno de escorpion y este efecto fue disminuido por el tratamiento con cimetidina y hexamethonium. Los efectos del veneno de B. eupeus sobre la secreción gástrica de la rata son debidas a un efecto neurotoxico a nivel pre y postganglionar parasimpático

Nesidioblastosis associated with chronic experimental pancreatitis produced by a scorpion toxin, tityustoxin, in rats

Tityustoxin (TsTx), the purified venom of the Brazilian scorpion Tityus serrulatus, was inected intravenously (50 microng/Kg) into rats, producing a typical picture of chronic pancreatitis after 20 days. Nesidioblastosis, a lesions characterized by hyperplasia of the islets of Langerhans, was also detected in a high percentage (40%) of animals. TsTx-induced pancreatitis may be a useful model for the study of nesidioblastosis in laboratory animals

Abnormal cardiovascular and electrocardiographic profiles and cardiac glycogen content in rabbits injected with scorpion venom.

Cardiovascular and ECG abnormalities were studied following injection of venom of Buthus tamulus, a common scorpion found in South India. Venom was administered in doses of 2 and 4 mg/kg body weight. Subsequent estimation of glycogen content of different chambers of the heart, showed a significant reduction in tissue glycogen levels in both atria and ventricles in animals treated with a venom dose of 2 mg/kg. However, a significant reduction occurred only in atria with a higher venom dose of 4 mg/kg.