The effects of vitamin C on some heamatological parameters and biomarkers of oxidative stress in albino wistar rats exposed to lead acetate over a short term (3 weeks) was investigated. Studies have revealed that lead has a wide range of health effects that can result from exposure, and that lead can cause health effects at blood lead levels previously thought to be safe. An increasing body of evidence suggests that lead is associated with a number of health conditions. Twenty albino wistar rats were randomly divided into four experimental groups of five rats each, Control group were fed normal rat feed with distilled water, Group 2,3 and 4 were fed normal rat feed, water and received daily oral administration of lead acetate 250mg/kg daily. In addition groups 3 and 4 received 100mg/kg and 150mg/kg oral administration of vitamin C respectively, for three weeks. Mild effect of lead acetate was observed in haematological parameters as indicated by slightly increase ,which was not statistically signifiant, in RBC and MPV. In contrast, a slight decrease was seen in haemoglobin, PCV, MCV, MCH, MCHC and platelet count. Descrease in MCV,MCH and MCHC indicated shrink in size of RBCs and onset of microcytic anemia due to onset of iron deficiency. However, derease observed was not stgatistically signifiant. Also the effect of lead acetate was mild on biochemical enzyme activities, indicated byincreased level of MDA activity; whih indicate oxidative stress,however the increase was not statistically significant. SOD and GPx level were slightly decreased, which was not statistially signifiant. The doses of vitamin C supplement did not reverse the effect of lead acetate on some haematological parameters and some biochemical enzyme activities, it however reverse the effect of lead acetate on MDA level. In conclusion, exposure to lead acetate over a short term has little effect on haematological parameters and biochemical enzyme activities. The doses of vitamin C use in this study has ameliorative effect on MDA activity but has no effect on some alteration on haematological parameters and some biochemical enzyme activities.

1.0   INTRODUCTION

Lead is a naturally occurring bluish-gray heavy metal found in small amounts in the earth‟s crust.

However, it is rarely found naturally as a metal. It is usually found combined with two or more other elements to form lead compounds (ATSDR, 2007). Metallic lead is resistant to corrosion (i.e., not easily attacked by air or water). When exposed to air or water, thin films of lead compounds are formed that protect the metal from further attack (ATSDR, 2007). Lead is poisonous when inhaled or eaten. Lead content in air, food and tap water has increased several folds during recent years due to extensive use of this metal in petrol, paints, battery and other industries (Tuarmaa, 1995). According to WHO (2000) lead is a metal with no known biological benefit to humans. Too much lead can damage various systems of the body including the nervous and reproductive systems and the kidney.

Generally, heavy metals produce their toxicity by forming complexes or ligands with organic compounds thereby affecting the function of biological molecules, inactivate some biochemical enzymes and affect protein structure (Pirkle, 1998) Because of its potential health problems, the amount of lead used in these products today has lessened or has been removed. Lead and other heavy metals create reactive radicals which damage cell structure including DNA and cell membrane (Flora, 2008). Lead poisoning can cause a variety of symptoms and signs which vary depending on the individual and the duration of lead exposure (Kosnett, 2005, Karri, 2008 ).

The amount of lead in blood and tissues, as well as the time course of exposure, determines the level of toxicity (Pearson and Schonfeld, 2003).