Neurotoxic and cytotoxic effects of venom from different populations of the Egyptian Scorpio maurus palmatus.

Neurotoxic and cytotoxic effects of venoms from Scorpio maurus palmatus taken from different populations were assessed for geographic based variability in toxicity, and to evaluate their insecticidal potency. Scorpions were collected from four regions. Three locations were mutually isolated pockets in the arid area of Southern Sinai. The fourth sample was collected from a population inhabiting the semi-arid environment of Western Mediterranean Coastal Desert. The neurotoxic (paralytic) effect of the venom from each population was assayed by its ability to induce permanent disability in adult cockroaches within 3h. Venom was applied using microinjection techniques through an intersegmental membrane. Probit analysis was used to calculate the Paralytic Effective Dose (PED(50), ng/100mg). Levels of glutathione, lipid peroxidation, protein carbonyl content and nitric oxide, as well as the activities of superoxide dismutase, catalase and cholinesterase, were measured to assess the cytotoxicity of the venom. The results show that the injected venom from each population induced obvious spasticity, followed by flaccid paralysis. All the tested biochemical parameters, except glutathione content, revealed significant differences in toxicity in venom taken from the different scorpion populations. We conclude that (i) the venom of this scorpion has significant neurotoxic and cytotoxic effects on insect cells, (ii) its efficacy, as assessed by the PED(50) unit, exhibited variation across its geographic range, and (iii) components in the venom may have the potential for being developed into effective and environmentally friendly bioinsecticides.

Effect of methimazole treatment on doxorubicin-induced cardiotoxicity in mice.

The major limiting factor in long-term administration of doxorubicin is the development of cumulative dose-dependent cardiomyopathy and congestive heart failure that limit the use of this drug. The present study was undertaken to find out the chemo protective role of methimazole against doxorubicin-induced cardiotoxicity in experimental animals. In the present study, doxorubicin treatment in a dose of 3mg/kg, i.p., every other day for six doses showed a significant 2.6-, 3- and 10.5-fold increase in the cardiac enzyme activities CK-MB and LDH and troponin-I, respectively, in the serum of the animals. Histopathological investigation of heart tissues showed swollen muscle fibers with interstitial edema and inflammatory exudate. Pretreatment of the animals with methimazole at a dose level of 40 mg/kg, i.p., 30 min before doxorubicin, returned the cardiac enzyme levels to nearly normal value with partial reversal of the inflammatory lesions and the swollen muscle fibers induced by doxorubicin. Moreover, methimazole pretreatment, decreased the doxorubicin level in the heart tissues with a significant increase in plasma level and non significant effect on doxorubicin level in tumor cells. At the same time, methimazole pretreatment did not significantly interfere with the antitumor activity of doxorubicin.