الفهرس 
CancerOnly 14 pages are availabe for public view
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Abstract
Given the lack of progress in curing metastatic epithelial
cancers, there is intense interest in, and a sound scientific
rationale for, pursuing strategies to prevent cancer.
However, although several clinical trials have shown
efficacy in cancer prevention, few have resulted in changes
to medical practice, and some trials have even shown harm.
Recent experiences with serious side effects identified in
cancer prevention trials underscore the need to re-evaluate
our approach to clinical chemopreventive drug
development.
The present study was done to evaluate the protective
effect of Ginkgo biloba extract and / or low dose gamma
irradiation on ferric nitrilotriacetate induced hepatic and
renal carcinogenesis in rats.
For this purpose eighty adult male albino (120-150 g)
rats were randomly distributed into 8 groups (each of 10
rats) as following :
group 1: Untreated control group.
group 2: Animals of this group received pretreatment
with ginkgo biloba extract (100 mg / kg / day ) 3 times per
week for 21 weeks.
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153
group 3: Animals of this group exposed to γ-radiation (50
cGy per week) for 19 weeks .
group 4: Animals of this group intraperitoneally injected
with Fe-NTA (9 mg Fe/kg body wt) twice a week for 20
weeks.
group 5: Animals of this group received pretreatment with
ginkgo biloba extract as described in group (2) and exposed
to γ-radiation as described in group (3).
group 6: Animals of this group received pretreatment with
ginkgo biloba extract as described in group (2) and
intraperitoneally injected with Fe-NTA as described in
group (4).
group 7: Animals of this group intraperitoneally injected
with Fe-NTA as described in group (4) and exposed to γ-
radiation as described in group (3).
group 8: Animals of this group received pretreatment with
ginkgo biloba extract as described in group (2),
intraperitoneally injected with Fe-NTA as described in
group (4) and exposed to γ-radiation as described in group
(3).
At the end of the experiment blood, liver and kidney
samples were collected for biochemical determinations and
histopathological observations.
Summary
154
The results were statistically analyzed and represented in
tables and figures. The gained results were summarized as
following :
ALT and AST activities were elevated in Fe-
NTA treated rats as well as BUN and creatinine
levels which reflect the hepatic and renal damage
that have been induced in these rats.
Fe-NTA injected groups showed a marked
depletion in GSH content, GPx, SOD and
catalase activities in blood, liver and kidney with
a significant increase in lipid peroxide and NO
levels in blood, liver and kidney compared to the
control group which indicate the highly oxidized
state of Fe-NTA treated rats.
Fe-NTA induced notable ROS, which played a
protective role in apoptosis by inhibiting
Caspase-3 activation in liver and kidney tissues
whole body γ-radiation exposure of rats caused severe
degenerative changes in liver and kidney tissues
resulted in a marked elevation in ALT and AST
activities and a significant increase in creatinine and urea
levels.
Summary
155
a considerable decrease in the levels of GSH, GSHPX
, catalase and SOD was observed in γ- irradiated
groups with a distinct increase in LPx level which
illustrate the damaging effect of low dose γ-
irradiation.
Pretreatment with G. biloba extract led to a
marked decrease in ALT, AST, creatinine and
BUN levels compared to the Fe-NTA treated rats.
Pretreatment of Fe-NTA treated rats with G.
biloba extract increased GSH content, Gpx, SOD
and catalase activities in blood , liver and kidney
of these rats with depletion in lipid peroxide and
NO levels.
GB Treatment caused a marked increase in levels
of liver and kidney Caspase-3 restoring its
anticarcinogenic effect by activation of apoptosis.
In conclusion, the results of the present study
indicate that low dose γ- irradiation produced a cytotoxic
damaging effect in blood, liver and kidney of irradiated
rats which is conversed with the expected effect.
Simultaneous treatment with G. biloba extract protects the
liver and the kidney against Fe-NTA and / or γ- irradiation
induced hepatic and renal cytotoxicity . These effects are
mainly attributable to the polyvalent actions of the
Summary
156
flavonoid constituents of GB, including their ability to
scavenge free radicals and to modulate signal transduction
pathways