الفهرس 
Materials and MethodsOnly 14 pages are availabe for public view
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Abstract
Biochemical influence of N-acetylcysteine and silymarin on arsenic
toxicity induced oxidative stress in rats were investigated. Moreover, the
possible protective effects of N- acetylcysteine and silymarin on serum
proteins, liver marker enzymes (AST,ALT ,ALP ,γ-GT) and bilirubin, proinflammatory
cytokines (TNF-α ,IL-6) , Hepatic tissue antioxidant enzymes
(CAT , GPX and SOD), GSH, oxidative stress markers (L-MDA, NO), bcl-
2, TGF-β1, NF-Kβ, 8-OHdG and Caspase3 in addition to liver DNA
damage as well as Cytochrome p4502E1 gene expression of liver in
arsenic intoxicated rats were also evaluated.
Seventy five white male albino rats, 12-16 weeks old and average
body weight 180-220 gm were used in the experimental investigation of
this study. Rats were housed in separate metal cages and kept at constant
environmental and nutritional conditions throughout the period of
experiment.
Experimental design:
After acclimatization to laboratory conditions the rats were randomly
divided into five equal groups, 15 rats each placed in individual cages and
classified as follows:
group I (control normal group): Comprised 15 male rats, received
no drugs, served as control non-treated for all experimental groups.
group II (sodium arsenate exposed group): Included 15 male rats,
received sodium arsenate 1/20 of L.D.50 orally and once per day over a
period of 8 weeks (41 mg/kg. body weight).
group III (sodium arsenate + N- acetylcysteine treated group):
Comprised 15 male rats, received sodium arsenate orally and daily at a
dose level of (41 mg/kg. body weight) and treated daily with n- acetyl
cysteine orally at a dose level of (200 mg/kg. body weight).
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Summary
group IV (sodium arsenate + silymarin treated group):Included
15 male rats, administrated daily with sodium arsenate at a dose level of
(41 mg/kg body weight/orally) and treated daily with silymarin at a dose
level of (200 mg/kg body weight/orally, daily).
group V (sodium arsenate + N-acetylcysteine + silymarin
treated group): Comprised 15 male rats, received sodium arsenate orally
and daily at a dose level of (41 mg/kg. body weight) and treated daily and
orally with both N- acetyl cysteine and silymarine at a dose level for each
(200 mg/kg. body weight).
Sampling:
Random blood samples and tissue specimens (liver) were collected
from all animals groups (control and experimental groups) two times along
the duration of experiment at 4 and 8 weeks from the onset of sodium
arsenate exposure and treatment with natural antioxidants.
Blood samples:
Blood samples for serum separation were collected by ocular vein
puncture at the end of each experimental periods in dry, clean and scrow
capped tubes and serum was separated by centrifugation at 2500 r.p.m for
15 minutes. The clean, clear serum was separated by automatic pipette and
received in dry sterile sample tubes, processed directly for hepatic marker
enzymes (AST, ALT, ALP and γ-GT) determination, then kept in a deep
freeze at -20 oC until used for subsequent biochemical analysis. All sera
were analyzed for the following parameters: total bilirubin, total protein,
albumin, interlukin-6 (IL-6), TNF- α, TGF-β1 and bcl-2.
218
Summary
Tissue specimens:
a-For biochemical analysis:
After four and eight weeks of treatment with NAC and or silymarin
the rats were sacrificed. Livers were removed, rinsed in ice-cold 0.9%
sodium chloride solution, quick frozen in a deep freeze at -20°C for
subsequent biochemical analysis.
Hepatic tissue preparation:
Briefly, hepatic tissues were cut, weighed and minced into small
pieces, homogenized with a glass homogenizer in 9 volume of ice-cold
0.05 mM potassium phosphate buffer (pH7.4) to make 10% homogenates.
The homogenates were centrifuged at 6000 r.p.m for 15 minutes at 4°C,
then the resultant supernatant were used for the determination of the
following parameters: NF-Kβ , NO, MDA, SOD, CAT, GPX, GSH,
Caspase3 and 8-OHdG.
b-For molecular analysis:
Tissue samples for RNA extraction and comet assay:
Liver tissues were collected from all animals groups (control and
experimental groups) at the end of each experimental periods. Tissue
samples were put in Eppendorf tube and were immediately kept in liquid
nitrogen and stored at -80°C till RNA extraction for determination of comet
assay and gene expression of cytochrome p4502E1.
c -For histopathological finding:
After eight weeks of treatment, liver and kidney specimens of rats
were carefully examined by naked eyes for detection of any abnormalities.
The specimens were preserved in 10% buffered neutral formalin and
subjected for microscopical examination.