الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 161 |  |  |
| | | from | 161 | | |
Abstract
Summary & Conclusion
Silymarin, frequently used in the treatment of liver disease, is a
flavonoid complex of sliybin, silydianin and silychristin. It is capable of
protecting liver cells directly by stabilizing the membrane structures,
including endoplasmic reticulum, by an effective decrease in membrane
permeability-and a change in lipid content in the membrane. Silymarin as
a therapeutic agent seems to be well tolerated and largely free from
adverse effects.
The present work was performed to investigate and assess the
radioprotective effect of silymarin, applied before irradiation, against
radiation-induced histological and histochemical changes of rat liver
cells.
Male albino rats have been used and classified into four groups as
follows:
1-Normal rats.
2- Rats irradiated at the dose 5 Gy of gamma rays.
3- Rats treated with silymarin as a single oral dose (70 mglkg.wt) and
then irradiated at 5 Gy of gamma rays.
4- Normal control rats (treated with silymarin as a single oral dose 70
mglkg.b.wt. only) and not irradiated.
lot
---- ’.--._ .. - ’-. -’---’-’- Summary & ConclUSion
AI1 th,,, ”,oup, of,,~ were sacr] fi”d arthe ”’n” in”””I,; ons
th,,,,, fiyo,’’’’’n and fn_n day,posr !reatm’n,””d the ”’ul~ nf the
present experiment revealed the following observations:
A
Th, h,,,,,,_,, are pnlyh_ in ”’”P< rel,tivoly1_ in ’i”
and exhi bit di’tin,’ limiting”””’b”””” ””h h_, ”11 has a ””’’’’’Iy
I””’ted nn,lon, with on, or twn pro”’in””, nn’ld, Nn””,”y the
h,p”Dey<” ’PP- ”’’’’’tim” binud”ted with _nl”, ””d
hnmng,nou,<ytopl asm , Th,b”Patncyte” are nuli”lydi,pn”” inthe liver
10bul” bur in ””pn””, to g’’’’n” -””on, the b””,lnc_ ””””’d
different pathological alterations as follows:
00 the fu” and thin!Pll<’””di’tion day”the h_,yte, ’b”””,
mndhY,”opI,d,g””””tion with Ioss of the Mnn” nuli” ”’uctm””
diJ,,,tionof the blOOdYO”’I, whi”, ”’’’’’”’’’ _”ted withblOOdin
’om, <oct of ””””n_g, ’n,,,,,,, withfutty;”m””tion of the ”””,,”,
P’”””,hyte” In_ -pl_, ”””o1ntlon, ’’’to’’’i” 1n>emmmag,
with increased inflammatory leucocytic infiltration Werealso seen.
P’’’in, to thofifth ””” -””on day,tho”””’- ””’- ”’’’’’’’d ’ign, of ”””””’’’’on ”””’” s__ tie cells __
,
di’tribu”d th”,”””o”, tho I1v” -on ”””””””’I”” by ’Ylopl_,
vVeosst,e”l”s.I”’on, futty d”’’’’’’’’’’tion and ”’’’’’’’’’’ dn’’’’’nn of th, blOOd
On the seventh post exposure day, some hepatocytes retained their
- -. whm ’om, binuel”””, cells wereseen,Kfippk,
cells Were normal in shape and size. Dilatation of the blood vessels were
also seen with the appearance of Some necrotic cells.
, .0
. -------.
-------------------- Summary & Conclusion
On the fourteenth post exposure day, different signs of
regeneration were seen where the hepatocytes appeared normal in shape
and size with the appearance of multinuclear forms, Kiipffer cells and
blood sinusoids were normal with marked inhibition of the inflammatory
reaction.
In the present work, silymarin administration one how before
irradiation, showed different signs of impro /ement in the hepatocytes
where the liver cells appeared regular with intact cell membranes and
prominent nuclei, indicating the prophylactic role of silymarin, as
manifested on the first and third post treatment days.
On reaching the fifth post treatment day, the hepatocytes showed
limited incidence of the inflammatory process with the appearance of
some thick-walled hepatocytes with densely stained nuclei indicating
progressive signs of proliferation. Moreover, the hepatocytes appeared
,
healthy with some binucleated cells on the seventh post treatment day and
such restoration process was continued till the fourteenth post treatment
day where the hepatocytes retained their normal shape and organization,
binucleate cells were prominent also.
Silymarin administration to normal control rats showed no
detectable changes in the histological pattern of the hepatocytes which
appeared normal in shape and size with one or two nuclei within with few
, tiny cytoplasmic vacuoles.
,.,
-------------------- Summary & Conclusion
B) Histochemical Alterations:
* General carbohydrates:
- In whole body gamma irradiated rats, there was an obvious
decrease in the total carbohYdrate content one and three days
post irradiation. This was followed by a marked increase in the
carbohydrate material on the fifth and seventh post exposure
day~. Finally, a nearly normal carbohydrate pattern: was seen
fourteen days after exposure.
- Silymarin administration to experimental animals before
irradiation showed a slight decrease in the carb9hydrate
material of hepatocytes one and three days post radiation
exposure at a degree less than that of irradiated non-treated
ones. Gradual and progressive increase in the PAS positive
material is seen on the fifth, seventh and fourteenth days post
silymarin administration and irradiation.
- Application of silymarin alone showed slight increase in the
carbohYdrate material from the first till the seventh post
application day then a decrease in the PAS positive material
could be seen at the fourteenth post administered day Whereits
carbohydrate content appeared in a degree to some extent
similar to that of the normal ones.
* Total proteins:
- Gamma irradiation showed a progressive and gradual increase
in the total protein content of the hepatocytes from the first till
the third post exposure days and a process of recovery began
daatyth. e fifth day and continued till the fourteenth post exposure
, •v
- ----- -- ----
---. - - -. -------
- - - --- --- ----
- ----------
----------------- _..’-- Summary & Conclusion
- Silymarin application before irradiation showed a well marked
increase in the protein content of the hepatocytes from the first
till the fifth post exposure days in a degree exceeding that
produced from i’r’ •diation only due t:J the double effect of
silymarin and irradiation. This is followed by a -phase of
recovery on the seventh day and completed at the fourteenth
day after silymarin administration and irradiation.
- Administration of silymarin alone caused an increase in the
protein content of the hepatocytes and such increase was
temporary and continued till the seventh day whereas the
status in the fourteenth day was nearly normal.
* Deoxyribonucleic Acid (DNA):
- In gamma irradiated rats, the hepatocytes showed marked
decrease in the DNA content and such decrease appeared
more prominent on the first and third post exposure’ days. A
gradual increase in the DNA content was seen at the fifth day
and became more obvious at the seventh and fourteenth days
post irradiatiqn,
- In silymarin administered and irradiated rats, there was a
marked improvement in the DNA picture of the hepatocytes
throughout the entire period of the experiment indicating the
prophylactic role of silymarin.
- Silymarin administration alone to normal control rats showed a
slight increase in the DNA content of the hepatocytes from the
first till the fourteenth day post application.
-------------------- Summary & Conclusion
from these results ”’\’(0 can conclude that, the prophylactic
administration of silymarin showed its marked radioprotective role in
liver cells which maybe due to:
- Silymarin’s ability to act as a free radical scavenger thereby
preventing membrane permeability changes.
- Silymarin increases the hepatocyte protein synthesis by stimulating
the activity of ribosomal RNA polymerase.
- Silymarin decreases the hepatic and mitochondrial glutathione
oxidation induced by iron overload and is a mild chelator of iron.
- Silymarin protects against radiation-induced suppression of hepatic
DNA and RNA synthesis.