Haemotoxic Effect of Lead: A Review

Abstract

Lead exposure is one of the major environmental issues to alter the health and well being of man and animals. Blood being the easy target for lead intoxication shows prominent effects and alteration of several hematological parameters may be regarded as a bio indicator of lead intoxication. Blood lead levels above 10 μg/dL have been associated with numerous manifestations. Anaemia is reported after acute and chronic exposure of lead in both workers of lead factory and in laboratory animals, accomplished either through impairment of heme biosynthesis or by enhanced rate of blood cell destruction. This is confirmed by marked reductions in blood haemoglobin level and haematocrit value and echinocytic transformation of normal erythrocytes after lead exposure. The number of total leucocytes tends to increase with the increase in basophils, eosinophils and lymphocytes possibly due to direct toxic action of lead on leucopoiesis in lymphoid organs. High levels of lead inhibit aggregation of platelets both in human and rat blood. Lead induced changes in the red blood membrane include the changes in lipids and proteins profile of some membrane-associated enzymes or in ions transport mechanisms. The mechanism of lead toxicity may be due, in part, to disruption of calcium-mediated processes. The chronic exposure to lead can result in a drastic changes in the cholesterol and phospholipid content, hexose, hexosamine and sialic acid levels and membrane acetyl cholinesterase, NADH dehydrogenase and Na+–K+ ATPase levels. Moderate exercise, intake of methionine, glycine, curcumin, methionine, carotene and pectin enriched food and vitamin C could reduce the severity of lead toxicity.