Abstract
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.
CHAPTER ONE
1.0 INTRODUCTION
1.1 GENERAL 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).