الفهرس 
Introduction & Aim of workOnly 14 pages are availabe for public view
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Abstract
Copper is an essential trace element involved in metabolic processes and has a role in the viability of numerous enzymes. Copper oxide nanoparticles (CuONPs) have received a lot of attention due to their remarkable conductive, optical, magnetic, and electrical properties. They are widely used in a variety of applications such as catalysis, optical sensors, electronics, superconductors, and the biomedical industry. CuONPs have essential applications in biomedicine, such as foot wear and blankets to reduce nosocomial infections in hospitals. They are a better choice as food additives because of their antibacterial properties. Furthermore, CuONPs can be used as strong antifungal and antibacterial agents in a variety of products ranging from cosmetics to insecticides. Several studies have shown that CuONPs, due to their small size and high reactivity, can produce a variety of harmful consequences, including hepatotoxicity.
As a result, there is a pressing need to mitigate the negative impacts of these necessary nanoparticles. In this arena, the utilization of nutraceuticals or botanical metabolites in conjunction with these nanoparticles may provide a safer platform.
Quercetin is a type of flavonoid found in a variety of fruits and vegetables, including cherries, broccoli, red onion, and mango. It has recently been demonstrated that quercetin has pharmacological significance due to its antioxidant, anti-inflammatory, antibacterial, antineoplastic, neuroprotective, and antiallergic properties. Because of these features, quercetin has received universal acceptance and considerable application in the healthcare industry.
L-Arginine is a semi-essential amino acid that is involved in a variety of biological processes. It is the substrate for a series of reactions that lead to the synthesis of other amino acids, and it is a substrate for two enzymes, nitric oxide synthase (NOS) and arginase, which are essential for the production of NO and urea, respectively.
Nitric Oxide produced from arginine is helpful in improving outcomes in various diseases. Therefore, arginine possesses a potent anti-stress activity, regulates cellular redox status, and plays an effective role against oxidative stress. Numerous studies have shown that L-arginine has a therapeutic effect in a variety of acute and chronic diseases including sickle cell anemia, pulmonary arterial hypertension, coronary heart disease, and pre-myocardial infarction.
Thus, this study aimed at investigating the potential hepatoprotective effect of quercetin or L-arginine and their combination against liver damage induced by copper oxide nanoparticles in adult male mice, as well as exploring the associated molecular mechanism.
A total of seventy adult male mice weighing 20-30 g, were used in this study. They were equally divided into seven groups (n=10).
group (1) control group, animals fed on a standard animal chow.
group (2) mice received 50 mg/kg of (L-Arg) dissolved in distilled water by oral gavage, day after day for 8 weeks.
group (3) mice received 50 mg/kg of (Qu) dissolved in warm distilled water by oral gavage, day after day for 8 weeks.
group (4) animals received 100 mg/kg of CuONPs suspended in distilled water by oral gavage, day after day for 8 weeks.
group (5) mice received the same previous doses of L-Arg and CuONPs concomitantly.
group (6) mice received the same previous doses of Qu and CuONPs concomitantly.
group (7) mice received L-Arg, Qu, and CuONPs concomitantly.
At the end of the experiment (8 weeks), the animals were weighed then anesthetized using isoflurane after fasting for 12h. Blood samples were withdrawn into capillary tubes from the retro-orbital venous plexus. Sera were prepared, then aliquoted and stored at -80°C until analysis. Immediately after sacrifice, liver tissue was perfused, dissected out, divided into three parts; the first part (" ~ " 0.1 g) was placed in sterilized microfuge tube and kept at-80˚C for assessing Caspase-3 and bax gene expression levels using qRT-PCR. The second part was kept in 10% formalin for histopathological examination using hematoxylin and eosin stain, and the third part was rinsed in isotonic saline solution, blotted dry with filter paper, weighed, and homogenized for biochemical assays. Serum was used to determine ALT, Total protein, and TNF-α.
Liver homogenate (10%) was used to determine arginase activity, NO, MDA, SOD, caspase-3 activity, and DNA fragmentation.
Results of the present study demonstrated that the oral administration of CuO NPs induced:
- A significant (P < 0.05) elevation of copper level in the hepatic tissue as compared to the control mice.
- Hepatic oxidative stress and lipid peroxidation indicated by a significant (P < 0.05) increase in hepatic NO and MDA levels which was accompanied with a significant (P < 0.05) decrease in SOD activity.
- A significant elevation of serum ALT accompanied with a significant (P < 0.05) reduction in the hepatic arginase activity.
- Liver tissue inflammation as seen by a significant (P < 0.05) rise in serum TNF-α level.
- A significant increase in DNA fragmentation assessed by Comet assay in liver tissue (tail DNA) by⁓ 106%.
– An elevation in the relative expression levels of hepatic caspase-3 and bax apoptotic genes.
- Higher activity of hepatic caspase-3 compared to normal group (P < 0.05), indicating hepatic apoptosis.
- Massive changes in liver architecture as manifested by markedly dilated central veins with detached lining, expanded portal tracts with markedly dilated congested portal veins, and a marked portal inflammatory infiltrate, compared with the normal hepatic architecture of untreated mice.
On the other side, treating mice with either quercetin or L-arginine and their combination along with CuO NPs significantly mitigated CuO NPS deleterious impact on hepatic tissue as indicated by:
- Significant prevention of copper accumulation in the liver tissue compared to the CuO NPs-intoxicated group.
- Significant improvement in the redox state of liver tissue and prevention of the elevation of MDA and NO levels and the reduction of SOD activity.
- The significant increase in arginase activity (P < 0.05) and reduction in serum ALT activity compared with CuO NPs-intoxicated group (P < 0.05).
- A considerable reduction in serum TNF-α level (P < 0.05) compared with the CuO NPs group.
- Significant reduction in the tailed DNA (P < 0.05).
- Marked reduction in the relative expression of the studied apoptotic genes (P < 0.05).
- Significant prevention of apoptosis and reduction of caspase-3 activity (P < 0.05).
In conclusion, the outcomes of the current research emphasized that CuONPs induced hepatic injury through triggering oxidative stress, inflammation, and apoptosis. Also, the study proved the efficiency of quercetin and L-arginine in mitigating CuO-NPs-induced liver toxicity due to their antioxidant and anti-inflammatory properties, and status of Qu as a good metal chelator.