The effect of the viper Cerastes cerastes cerastes venom and venom fractions on carbohydrate metabolism

Foraging behaviour, habitat use and population size of the desert horned viper in the Negev desert

The desert horned viper occurs in the dunes of the northwestern Negev desert, Israel. We report on a 2 year study on the viper's behaviour and ecology in its natural habitat. We examined whether the vipers moved faster in a vegetation-dense microhabitat versus an open dune area and detected much slower movement in the former. We nevertheless detected no preference of the vipers for any of the dune areas. We suggest that the vipers trade-off the ease of movement on open areas with prey, which is probably more available in areas with denser vegetation. The activity was higher early in the season and the vipers were mostly active right after sunset, with a second smaller activity peak at sunrise, perhaps searching for burrows to spend the day. Fitting this explanation, movement at the track's end was less directional than at its beginning. We found inter-sexual and between-year differences. For example, females were larger than males in the second year of the study but not in the first one and the population seemed to be smaller in the second year of the study than in its first year. The information we provide on this viper may assist its conservation, as sand dunes are threatened habitats in Israel.

Histological, molecular and biochemical detection of renal injury after Echis pyramidum snake envenomation in rats

Nephrotoxicity is a common sign of snake envenomation. The present work aimed to clarify the effect of intraperitoneal injection of 1/8 LD50 and 1/4 LD50 doses of Echis pyramidum snake venom on the renal tissue of rats after 2, 4 and 6 h from envenomation. Histopathological examination showed intense dose and time dependent abnormalities, including swelling glomerulus and tubular necrosis and damage as well as signs of intertubular medullary hemorrhage at early stages of envenomation. However, at late stages of envenomation by any of the doses under investigation, no intact renal corpuscles were recorded and complete lysis in renal corpuscles with ruptured Bowman's capsules was observed. Immunohistochemistry by immunohistochemical staining was used to test the protein expression of Bax in renal tissue of rats. The result showed that the expression of Bax in renal tissue sections of envenomated rats was increased according to dose and time-dependant manner. The isolation of DNA from the renal cells of envenomed rats pointed out to the occurrence of DNA fragmentation, which is another indicator for renal tissue injury especially after 6 h of 1/4 LD50 of E. pyramidum envenomation. Oxidative stress biomarkers malondialdehyde and nitrite/nitrate levels, antioxidant parameters; glutathione, total antioxidant capacity and catalase were assayed in renal tissue homogenates. The venom induced significant increase in the levels of malondialdehyde and nitrite/nitrate while the levels of glutathione, total antioxidant capacity and catalase were significantly decreased, especially after 6 h of envenomation. The results revealed that the E. pyramidum induced dose and time-dependant significant disturbances in the physiological parameters in the kidney. We conclude that the use of the immunohistochemical techniques, the detection of DNA integrity and oxidative stress marker estimations are more specific tools that can clarify cellular injury and could point out to the defense activity of the renal tissue at envenomation.

Possible recovery from an acute envenomation in male rats with LD50 of Echis coloratus crude venom: I-A seven days hematological follow-up study

The effect of an acute LD50 dose of Echis coloratus crude venom in male albino rats was tested on blood parameters: white blood cells (WBCs), red blood cells (RBCs), platelets count, hemoglobin, hematocrit, mean cell volume (MCV), mean cell hemoglobin (MCH) and mean cell hemoglobin concentration (MCHC), also serum glucose, total protein, triglycerides with alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP) and γ-glutamyl transferase (GGT) enzyme activities. The effect of the LD50 dose was monitored over a period of seven days, with time intervals of 1, 3, 6, 12, 24, 72 h. All of the tested parameters show fluctuations with time and with tendency to regain normal control level after 12 h. At 12-24 h it seems to be crucial for the process of physiological recovery, in spite of the irreversible damage and tissue distraction. The process of physiological adaptation and recovery from the lethal destructive venom effect seems to stabilize after one week, leaving the animal alive with several biochemical altered metabolisms and disturbed physiological profile.

Fractionation and characterization of Cerastes cerastes cerastes snake venom and the antitumor action of its lethal and non-lethal fractions

In the present study fractionation of the Cerastes cerastes cerastes snake venom by gel filtration on Sephadex G-75 gave 14 protein fractions. Phospholipase PLA2 activity is not uniformly correlated with the lethality to mice in regard to all venom fractions. F11 which is the richest in PLA2 activity is less toxic than F3, which contains a small amount of PLA2, and F12 is the lowest in lethality and PLA2 activity. Treatment of Ehrlich ascites-bearing mice with two i.p. injections of the most lethal fraction (F3) or a non-lethal fraction (F4) resulted in a significant antitumor activity demonstrated by an increase in the mean survival time of the animals (22.5 and 27.9 days) and in the tumor inhibition ratio of tumor growth (T/C% 139 and 172, respectively), compared to tumor-bearing controls. The cytotoxic activity of F3 and F4 against Ehrlich ascites carcinoma cells might be due to the presence of a cytotoxin rather than to the direct cytolytic effect of the PLA2 because the non-lethal F4 is free from PLA2. Treatment of Swiss albino mice with two i.p. injections of F3 or F4 at the adopted dose levels produced no detrimental side effects demonstrated by the insignificant changes in the tested serum and liver parameters. Treatment of the tumor-bearing mice with the same venom fractions significantly modulated all of the studied biochemical parameters in the serum and liver tissues, compared to normal controls.