Pharmacology & Toxicology Poster Session
The toxicity and limitations of EDTA in its clinical application and animal experiments has been well studied. The present study was conducted to assess the roles of divalent cations of calcium and magnesium on the cytotoxic mechanisms of EDTA. Using a micro-modification of the standard complement hemolytic assay, 40µl of 5 x 108 non-sensitized rabbit red blood/ml are added to obtain a total reaction volume of 400µl.buffer containg a final EDTA concentration of 10mM, with different concentrations of calcium and magnesium ions. The reaction mixture was incubated for 60 minutes at 37°C, with occasional mixing. EDTA had no direct toxic effect on the cells in the absence of extracellular calcium and magnesium ions. While magnesium enhanced EDTA toxicity in a dose-dependent fashion up to 50mg/ml concentration, Calcium demonstrates a bimodal action on the toxicity of EDTA. Low concentrations up to 5mM enhanced EDTA cytotoxcity while higher concentrations inhibited toxicity, both in a dose-dependent fashion. EDTA has been shown to be capable of penetrating biological membranes and tissue stroma, its toxicity might therefore be related to intracellular non-specific chelation of ions. These cations probably also assist in the indispensable step of intracellular transport of EDTA to effect its toxic effects.
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|Ogundele, M.O.; (1998). the Role of Divalent Cations in the Mechanisms of EDTA Cytotoxicity. Presented at INABIS '98 - 5th Internet World Congress on Biomedical Sciences at McMaster University, Canada, Dec 7-16th. Available at URL http://www.mcmaster.ca/inabis98/pharmtox/ogundele0173/index.html|
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