الفهرس 
ACKNOWLEDGMENT
IntroductionOnly 14 pages are availabe for public view
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Abstract
It is concluded from the present study that:
1. Oral administration of lead acetate in drinking water for
six weeks resulted in severe damages of the histological
sections of liver, kidney, spleen, stomach, intestine and
testis of male albino rats. Impaired oxidant/antioxidant
balance may be responsible for the toxic effects of lead.
2. The co-administration of DMSA with lead acetate reduced
the toxic effect of lead in all the histological sections of
the tissues used in the present study. The chelating action
of DMSA for lead may be responsible for reducing the
cellular toxicity of lead.
3. The co-administration of lead acetate with both vitamin C
and vitamin E resulted in an improvement of the
histopathological changes that are induced by lead acetate.
This improvement may be due to the antioxidant activity
of vitamins C and E which protect the cells from oxidative
stress and used in the treatment of lead toxicity in soft
organs.
4. The administration of lead acetate combined with DMSA
and both vitamins C and E overcome the histopathological
changes that are produced by lead acetate in liver, kidney,
spleen, stomach, intestine and testis of albino rats in the
present study. It is known that DMSA acts as a chelating
agent of lead in soft tissues, and vitamins C and E acts as
antioxidant which prevent the generation of reactive
oxygen species (ROS) and alternation of antioxidant
defense system in animals as a result of exposure to lead.
Hence, DMSA as a chelating agent for lead and vitamins
C and E caused stoppage of oxidative stress by its
Conclusion and Summary
106
antioxidant activities and restore the normal histological
pictures of organs examined in the present study.
Summary
Lead is one of the most abundant heavy metals on the
earth. It has been widely used throughout human history,
posing a serious health problem to susceptible populations and
animals. It induced many biological effects on animals and
humans. Lead toxicity includes damage to soft tissues, such as
liver, kidney, spleen, gastrointestinal tract and reproductive
system. The adverse effects of lead on the histological sections
of the organ used in the present study may be mediated by
oxidative damage and subsequent lipid peroxidation. DMSA is
a chemical derivative of dimercaptol. It contains two sulfhydryl
(-SH) groups and has been shown to be an effective chelator of
toxic metals mainly lead and arsenic. For major advantages of
DMSA include its low toxicity, oral administration and no
redistribution of metal from one organ to another. DMSA has
been tried successfully in animals. Animal studies suggest that
DMSA is an effective chelator of heavy metals in soft tissues.
Vitamin C is a water-soluble antioxidant occurring in the
organism as an ascorbic anion. It also acts as a scavenger of
free radicals and plays an important role in the regeneration of
α-tocopherol. Vitamin E (α-tocopherol) is a fat-soluble vitamin
known to be one of the most endogenous antioxidants. α-
tocopherol is a term that encompasses a group of potent, lipid
soluble, chain-breaking antioxidants that prevents the
propagation of free radical reactions. It is known that the coadministration
of vitamins C and E is useful for reducing the
oxidative stress of lead exposure and improves the prooxidant/
antioxidant balance of cells. Thiol-containing
Conclusion and Summary
107
compounds bind lead at their –SH (thio) groups. Therefore the
combination of thiol-containing compounds (e.g. DMSA) with
antioxidants (e.g. vitamins C and E) may be useful as a
compound of an effective treatment for lead toxicity. This
study also, aimed to investigate the importance of DMSA as a
chelating agent of lead, vitamins C and E, as antioxidants, in
the treatment of the toxic effects of lead on histological
sections of liver, kidney, spleen, stomach, intestine and testis of
albino rats.
Thirty male albino rats (Rattus rattus) approximately 8-
10 weeks old, their weight ranging from 160-180 gm. are used
in the present study. They were divided randomly into five
groups (6 rats each). The first group served as control. The
second group received 100 ppm of lead acetate in drinking
water daily for six weeks. The third group received lead acetate
(100 ppm) daily in drinking water and 50 mg/Kg/body wt.
DMSA two times per week for six weeks. The fourth group
received lead acetate daily (100 ppm) in drinking water, 50
mg/Kg/body wt. vitamin E and 160 mg/Kg/body wt. vitamin C
two times per week for six weeks. Whereas, the fifth group
received lead acetate (100 ppm) in drinking water daily; and 50
mg/Kg/body wt. DMSA, 50 mg/Kg/body wt. vitamin E and
160 mg/Kg/body wt. vitamin C two times per week for six
weeks. At the end of the experiments, rats from each group
were anesthetized, then sacrificed by decapitation. After the
animal dissection, liver, kidney, spleen, stomach, intestine and
testes were taken and prepared for histological examination.
• The results indicated that lead induced severe
histological changes in liver, kidney, spleen, stomach,
intestine and testis sections from rats.
Conclusion and Summary
108
• The histological examination of the liver, kidney,
spleen, stomach, intestine and testes sections from the
rats treated with lead acetate combined with DMSA
showed mild histopathological changes as an indication
of the chelating action of DMSA.
• The administration of lead acetate combined with both
vitamins C and E reduced to greater extent the toxic
effects of lead acetate on the histological sections of the
rat organs used in the present study. These results
revealed that the combination of vitamins C and E as
antioxidants may be a beneficial treatments for lead
toxicity in soft organs.
• Co-administration of rats with lead acetate, DMSA,
vitamin C and vitamin E showed a marked
improvement in the histological structure of the
histological sections of the rat organs used in the
present study. In comparison with those treated with
either DMSA alone, or the combination of vitamin C
and vitamin E. These results indicate that the
combination of DMSA, as a chelating agent and
vitamins C and E, as antioxidants, provided a better
treatments for the removal the histopathological
changes induced by lead toxicity in soft tissues used in
the present study