الفهرس 
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Abstract
Liver fibrosis become widely distributed worldwide, in practice field we can cause it by several models witch cause induced hepatitis by several drugs as D–galactosamine and lipopolysaccharide which cause hepatitis due to the effect of reactive oxygen species that have a superior effect on liver functions and oxidative parameters.
D-galactosamine and lipopolysaccharide cause liver damage similar to that caused by human virus infections due to oxidation by reactive oxygen species and elimination of antioxidant parameters.
We aimed to investigate the effect of cerium oxide nanoparticles which have a potent antioxidant effect that counteract oxidative stress and remove oxidative parameters by several biochemical reaction in the cell.
from genetic aspect illustration of antioxidant defence is controlled mainly by NrF2 in the cytoplasm witch separated from KEEP1 and translocate into the nucleus on antioxidant response elements(ARE) to cause formation of antioxidant elements as HO-1.
The recent formed nanoparticles have potent effects in several fields especially witch is related to human health as cerium oxide nanoparticles due to reduction properties that promote it’s protection effect on liver cells from oxidative stress and free radicals against chemicals and biological radiations and increase longevity of cell and counteract oxidative stress toxicity and free radicals formation.
These nanoparticles have ionic properties witch exchange between 3+ and 4+ to allow it to interact in oxidative reaction and their applications.
Cerium oxide nanoparticles injected to rates before toxicity attach with D-galactosamine and lipopolysaccharide as prophylactic doses
Eighty male Wister albino rats were used in this study. They were divided into four groups; each group was comprised of ten animals.
(Control group): kept as a control negative and it was received a sterile physiological normal saline (0.5 ml IP).
(D-GALN/LPS group): Control positive group as the rats were received simultaneously a single dose of (D- galactosamine (130 mg/ Kg IP) and lipopolysaccharide (100 ng/ kg IP).
(The cerium oxide, D-GALN / LPS group): The rats were given CeO2 nanoparticles (0. 01 µg/ kg IP) on days 1, 3, 5 and 7. Then it was given a single dose of (D- galactosamine (130 mg/ Kg) and lipopolysaccharide (100 ng/ kg) IP simultaneously as a single dose.
(Cerium oxide group): The rats were given CeO2 (0. 01 µg/kg; 0.5 mL in PBS IP) on days 1, 3, 5& 7.
After 18 hour of overnight fasting, the blood samples were collected from the medial canthus blood capillaries of the eye in dry clean centrifuge tubes for separation of serum which was kept at -20˚C for determination of ALT and AST. Then the rats were sacrificed and the livers were excised, and divided into four parts, the first part of them were placed in proteinase inhibitor and preserved at -80˚C for western blot analysis. A second part of liver was placed in RNase inhibitor and preserved in at -80˚C for RT-PCR. Third part of the liver was homogenized in 5 ml phosphate buffered saline by using tissue homogenizer. The liver homogenates were centrifuged at 10,000 rpm for 15 minutes. The supernatants were collected and used directly for measurement of GSH, GR, CAT , SOD, LPO and DNA fragmentation percent levels. The last part of the liver was preserved in 10% formalin solution for histopathological examination.
The results revealed that:
In D-GALN/LPS treated group HO-1 and INOS were elevated compared to those of normal control group. In addition, D-GALN/LPS treated group showed a significant decrease in NrF2 and GPX1 levels compared to those of normal control group. Also, D-GALN/LPS treated group showed a significant increase in serum ALT and AST activities and LPO and DNA fragmentation percent levels with subsequent decreased in GSH level, GR, CAT, and SOD activities compared to that of normal control group. These alterations induced by D-GALN/LPS were supported by the histopathological pictures of rat livers intoxicated with D-GALN/LPS that showed highly vacuolated hepatic lobules, which lost their endothelial cells. They also showed progressive degenerative changes of hepatocytes which were ranging from cloudy swelling, hydropic degeneration, vacuolation, pyknosis, kayrolysis and loss of architecture of some cells.
In contrast, administration of cerium oxide nanoparticles to D-GALN/LPS treated rats showed a significant decrease in HO-1 and INOS. Additionally, NrF2 levels and activities of GPX1 were significantly increased in curative and prophylactic groups of cerium oxide nanoparticles group compared to those of D-GALN/LPS treated animals. Also, the serum ALT and AST activities were also reduced in curative and prophylactic groups of cerium oxide nanoparticles compared to D-GALN/LPS treated animals. On the other hand, lipid per oxidation status (LPO level) and DNA fragmentation percent were significantly reduced, while the level of GSH and the activities of antioxidant enzymes (GR, CAT and SOD) were improved compared to those of D-GALN/LPS treated group. Histopathological pictures of liver sections of rats intoxicated with D-GALN/LPS and treated with cerium oxide nanoparticles appeared more or less like normal with an improvement in the liver architecture compared to those of D-GALN/LPS treated group.
Toxicity of liver cells is indicated by elevation of liver enzymes as ALT and AST witch alleviated by cerium oxide nanoparticles injection ,and indicated also by translocation of NrF2 from cytoplasm into the nucleus after separation from Keep 1 ,NrF2 conjugate to antioxidant response element and promote production of HO-1 that indicated by RT-PCR .
Ho-1 promote production of GPX1 witch indicated by RT-PCR and increase formation of antioxidant parameters as glutathione, glutathione reductase, catalase and sodium dismutase.
Oxidative stress of liver promotes production of NO, and subsequency INOS mainly due to inflammation effect of LPS.
Due to oxidative stress free radicals increase production of LPO and also cause increase percentage of DNA fragmentation.
These findings is confirmed by histopathological examinations that showing severe degeneration, haemorrhages and widened sinusoids. These findings alleviated by cerium oxide nanoparticles.
from our results we indicate that toxicity processed by D-galactosamine and lipopolysaccharide were alleviated by cerium oxide nanoparticles due to scavengering properties of their active sites on their surface and elimination of free radicals that cause oxidative stress and toxicity.
Conclusion:
Toxicity of liver cells can be performed by D-galactosamine and lipopolysaccharide witch is similar to liver toxicity induced by virus infection
Treatment of liver toxicity by oxidative stress can be achieved by usage of cerium oxide nanoparticles when used as prophylactic model to alleviation of toxicity.
Cerium oxide nanoparticles showed no harmful effect on cell properties and biological chemical reaction witch investigate that it have inert effects on cell and can be used safely in biological treatment.
Figure (22 ) diagram of toxicity of the liver pathways and alleviation of toxicity by cerium oxide nanoparticles.