الفهرس 
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Abstract
The present work was performed to study the
protective effect of melatonin and vitamin C as an
antioxidants and free radical scavengers on the oxidative
stress and morphological changes induced by monosodium
glutamate MSG administration to male albino rats. In this
study, the LPO levels, SOD activity and GSH concentration
as well as the morphological changes in the liver and
kidneys were examined.
The present work design
The animals were then divided randomly into five groups as
follow:
Group (I): Served as control where rats were injected with
vehicle alone.
Group (II): Animals were given MSG (0.5 gm / 100 gm b.
w) orally for one month.
Group (III): Animals were given MSG + Melatonin at a
dose of 10 mg / Kg b. w orally. Melatonin was given 30
minute before the administration of MSG to study the
protective role of melatonin.
Group (IV): Animals were given MSG + Vitamin C at a
dose of 100 mg /Kg b. w. orally. Vit.C was given 30 minute
before the administration of Group (V): Animals of this group were given MSG +
(Melatonin & Vitamin C) orally alternatively day by day at
the same dose of each substance.
The main results obtained from this study are
summarized as the follow:
• Monosodium glutamate greatly stimulated lipid
peroxidation in liver and kidney homogenates as
measured by the increase of malondialdehyde levels.
• Melatonin and vitamin C exerted a powerful inhibitory
effect on the levels of the lipid peroxidation in all
examined tissues compared to those administered with
MSG and our result indicated that melatonin was more
effective than vitamin C in reduced LPO levels in
treated tissue.
• MSG administration greatly stimulated SOD activity
in liver, contrary inhibited SOD activity in the kidney.
Also MSG inhibited GSH concentration in both liver
and kidney.
• Melatonin exerted a powerful inhibitory SOD activity
in the liver and stimulatory effect in SOD activity in
the kidney and GSH concentration in the liver and
kidney.
• Vitamin C proved to have strong inhibitory effect on
the SOD activity in the liver and stimulatory effect in
SOD activity in the kidney and GSH concentration in
the liver and kidney.• MSG markedly induced severe macro-morphological
and micro-morphological changes in all the examined
tissues (light and transmission electron microscopy)
compared with controls.
• Melatonin proved to have strong effect in the
prevention of MSG toxicity in the treated tissues liver
and kidney.
• MSG administration markedly increased the amount
of connective tissue fiber in the hepatic and renal
tissues versus to those of control rats
• Melatonin and vitamin C administration reduced the
amount of connective tissue fiber in the studied
organs.
• MSG markedly reduced the amount of carbohydrate
materials in both the liver and kidney cells versus
control animals.
• Both melatonin and vitamin C administration
increased the amount of carbohydrate material in both
the liver and kidney cells versus those of MSGadministered
rats.
• Regarding the morphological changes in the liver, comparing
between the protective efficiency of melatonin and vitamin C
one can realize the following:
• Melatonin exerted more protective effect than vitamin C in
the morphological structure restoration. Regarding the
connective tissue fiber formation, both melatonin and vitamin
C exerted nearly the same protective effect. However, the content of carbohydrate materials restoration was strong by
vitamin C administration than did by melatonin.
• The combination of both melatonin and vitamin C together
was more effective and beneficial in competing oxidative
stress induced by MSG than separate administration.