ABSTRACT
Los accidentes ofídicos representan un problema de salud pública que afecta más de 5000 personas anualmente en Venezuela. La composición química de los venenos de serpientes es muy compleja, aún cuando sean de la misma especie, entonces es importante conocer su bioquímica y farmacología para comprender su acción tóxica sobre los tejidos y por lo tanto la fisiopatología del emponzoñamiento. En este estudio se evalúa la toxicidad In Vivo e In Vitro del veneno de la serpiente Porthidium lansbergii rozei; el mismo se realizó en dos fases de laboratorio (In Vitro e In Vivo), con veneno extraído manualmente de una serpiente y administrado a 18 ratones albinos (Mus musculus) de la cepa BALB/C. Se hizo la caracterización del veneno determinándole peso específico, concentración de proteínas, actividad de la fosfolipasa A2, actividad proteolítica, acción de miotoxinas y actividades necrótica y hemorrágica. In Vitro se determinó que el veneno posee 18% de proteínas totales, peso específico de 1,416mg/ ml, actividad fosfolipásica dosis dependiente (a mayor sustrato mayor actividad) y 3,4% de proteólisis. In Vivo se comprobó que el veneno es principalmente miotóxico y hemorrágico elevando los valores promedios de CK de 9071,33±12,50UI/l a 9128,33 ± 21,59UI/l y creando un área hemorrágica promedio de 32,5±0,7071mm2 con una actividad necrótica promedio de 6±1,41mm2. El veneno de Porthidium lansbergii rozei tiene un efecto hemorrágico y miotóxico menor con relación a otras especies Viperidas, que podría deberse a una alta actividad fosfolipásica y moderada actividad proteolítica.
The ophidian accidents represent a problem of public health that it affects more than 5000 persons anually in Venezuela. The chemical composition of the poisons of serpents is very complex, even when they are of the same species, therefore it is important to know his biochemistry and pharmacology in order to understand his toxic action on the fabrics and therefore the pathophysiology of the poisoning. In this study In Vivo evaluates the toxicity and In vitro of the poison of the serpent Porthidium lansbergii rozei; the same was conducted in two phases of laboratory (In vitro and In Vivo), with poison extracted manually from a serpent and administered to 18 albino mice (Mus musculus) of the vine-stock BALB/C. The characterization of the poison became determining specific weight, concentration of proteins, Activity of the phospholipase A2, activity proteolytics, action of myotoxins and activities necrotic and hemorrhagic. In vitro one determined that the poison possesses 18% of total proteins, specific weight of 1,416mg/ml, activity phospholipasic dependent dose (to major major substratum activity) and 3,4% of proteolysis. In Vivo it was verified that the poison is principally myotoxic and hemorrhagic raising CK's average values of 9071,33±12,50UI/l to 9128,33 ± 21,59UI/l and creating a hemorrhagic average area of 32,5±0,7071mm2 with an activity necrotic average of 6±1,41mm2. The poison of Porthidium lansbergii rozei has a hemorrhagic effect and myotoxic minor with relation to other species Viperids, that could be cause of a high phosfolipasic activity and a moderate protelitical action.
ABSTRACT
We report a comparative venomic and antivenomic characterization of the venoms of newborn and adult specimens of the Central American rattlesnake, Crotalus simus, and of the subspecies cumanensis, durissus, ruruima, and terrificus of South American Crotalus durissus. Neonate and adult C. simus share about 50% of their venom proteome. The venom proteome of 6-week-old C. simus is predominantly made of the neurotoxic heterodimeric phospholipase A(2) (PLA(2) crotoxin) (55.9%) and serine proteinases (36%), whereas snake venom Zn(2+)-metalloproteinases (SVMPs), exclusively of class PIII, represent only 2% of the total venom proteins. In marked contrast, venom from adult C. simus comprises toxins from 7 protein families. A large proportion (71.7%) of these toxins are SVMPs, two-thirds of which belong to the PIII class. These toxin profiles correlate well with the overall biochemical and pharmacological features of venoms from adult (hemorrhagic) and newborn (neurotoxic) C. simus specimens. The venoms of the South American Crotalus subspecies belong to one of two distinct phenotypes. C. d. cumanensis exhibits high levels of SVMPs and low lethal potency (LD(50)), whereas C. d. subspecies terrificus, ruruima, and durissus have low SVMP activity and high neurotoxicity to mice. Their overall toxin compositions explain the outcome of envenomation by these species. Further, in all C. simus and C. durissus venoms, the concentration of neurotoxins (crotoxin and crotamine) is directly related with lethal activity, whereas lethality and metalloproteinase activity show an inverse relationship. The similar venom toxin profiles of newborn C. simus and adult C. durissus terrificus, ruruima, and durissus subspecies strongly suggests that the South American taxa have retained juvenile venom characteristics in the adult form (paedomorphism) along their North-South stepping-stone dispersal. The driving force behind paedomorphism is often competition or predation pressure. The increased concentration of the neurotoxins crotoxin and crotamine in South American rattlesnake venoms strongly argues that the gain of neurotoxicity and lethal venom activities to mammals may have represented the key axis along which overall venom toxicity has evolved during Crotalus durissus invasion of South America. The paedomorphic trend is supported by a decreasing LNC (lethal neurotoxicity coefficient, defined as the ratio between the average LD(50) of the venom and the crotoxin + crotamine concentration) along the North-South axis, coincident with the evolutionary dispersal pattern of the Neotropical rattlesnakes. The indistinguisable immunoreactivity patterns of Costa Rican and Venezuelan polyvalent antivenoms toward C. simus and C. durissus venoms strongly suggest the possibility of using these antivenoms indistinctly for the management of snakebites by adult C. simus and by certain C. d. cumanensis populations exhibiting a hemorrhagic venom phenotype. The antivenomic results also explain why the antivenoms effectively neutralize the hemorrhagic activity of adult C. simus venoms but does not protect against adult C. durissus sp. and newborn C. simus envenomations. The identification of evolutionary trends among tropical Crotalus, as reported here, may have an impact in defining the mixture of venoms for immunization to produce an effective pan-American anti-Crotalus antivenom.