Amelioration of oxidative stress-mediated apoptosis in copper oxide nanoparticles-induced liver injury in rats by potent antioxidants

www.nature.com/scientificreports OPEN Amelioration of oxidative stress‑mediated apoptosis in copper oxide nanoparticles‑induced liver injury in rats by potent antioxidants Samy A. Abdelazeim1*, Nagwa Ibrahim Shehata1, Hanan Farouk Aly2 & Shams Gamal Eldin Shams2 The purpose of this study is to investigate the therapeutic efficacy of individual or combined doses of dehydro-epiandrosterone (DHEA) and quercetin in ameliorating some biochemical indices in liver of CuO-NPs intoxicated-rats. CuO-NPs (50 nm) was administered as a daily oral dose 100 mg/ kg for 2 weeks to rats followed by the fore-mentioned antioxidants for 1 month. We highlighted the therapeutic effect of DHEA and quercetin against CuO-NPs toxicity through monitoring the alteration of liver enzyme activity, antioxidant defense mechanism, necrosis, apoptosis, histopathological alterations, and DNA damage. The rats given CuO-NPs only showed marked significant elevation in liver enzymes, alteration in oxidant-antioxidant balance and an elevation in the hepatic inflammatory marker; tumor necrosis factor-α. Additionally, over expression of both caspase-3 and Bax proteins were detected. Whereas, Bcl2 was down regulated and DNA fragmentation was elevated. Moreover, Histopathological examination of hepatic tissue reinforced the previous biochemical results. Co-treatment with either DHEA, quercetin alone or in combination ameliorated the deviated parameters with variable degrees against CuO-NPs toxicity in rat. In conclusion, our findings suggested that the aforementioned treatments exert therapeutic effect in CuO-NPs toxicity by diminishing oxidative stress, mRNA gene expression and hepatic tissues DNA damage. Nanotechnology is now involved widely in human lives with a lot of applications, especially in medicine, biological sciences, diagnosis, drug delivery, food industry, paints, electronics, sports, environmental cleanup, cosmetics and sunscreens1. Copper oxide nanoparticles (CuO-NPs) were among the first engineered nanoparticles, due to their exclusive properties and essential applications in magnetic, thermal, electrical and sensor devices as well as cosmetics. This makes human beings exposed to CuO-NPs and their potential adverse e ffects2. Biodistribution experiments revealed that liver, kidney and spleen are the target organs for engineered nanoparticles after uptake by the gastrointestinal t ract3. Due to their minute size and surface properties, metal oxide NPs may cross biological barriers and accumulate in different o rgans4. It has been stated that liver is one of the most targeted organs for NPs after they enter the body through any r oute5. Several studies have shown that NPs have cytotoxic effect in liver c ells5,6. However, the primary mechanism of apoptosis in liver cells due to CuO-NPs exposure is largely deficient. The key process in cancer development and progression is apoptotic cell d eath7. The ratio of Bax/Bcl-2 represents a cell death switch, leading to a poptosis8. Bcl-2 protein has an anti-apoptotic effect, whereas Bax is known for its pro-apoptotic e ffect9. Moreover, apoptotic stimuli leading to destabilization of the mitochondrial integrity precedes activation of caspases which play a central role in the execution of a poptosis10. It has been reported that there is a direct link between oxidative stress, genotoxicity, and a poptosis11. Oxidative stress plays an important role in the mechanism of toxicity of many compounds either by the production of 1 Biochemistry Department, Faculty of Pharmacy, Cairo University, Cairo, Egypt. 2Therapeutic Chemistry Department, National Research Center, Dokki, Giza, Egypt. *email: Scientific Reports | (2020) 10:10812 | https://doi.org/10.1038/s41598-020-67784-y 1 Vol.:(0123456789) www.nature.com/scientificreports/ reactive oxygen species (ROS) or by depletion of the cellular antioxidant capacity. Oxidative stress also, affects cellular integrity when the generation of ROS exceeds the antioxidant defense m echanism12. There are many evidences showing that NPs amplify ROS generation that were the main cause of cell death in several types of cultured cells13,14. The human body is constantly attacked by chemicals that may cause DNA damage by non-oxidative and oxidative mechanisms, which can lead to carcinogenesis. For detecting and analyzing DNA damage and repair at a single cell level in a variety of organs and cells of mammals, the comet assay is used which is a simple, rapid and sensitive gel electrophoresis technique15. The comet assay is widely used in monitoring and assessment of genotoxicity as, it allows any viable eukaryotic cell to be analyzed for DNA damage16. Moreover, the comet assay can be applied in other studies including DNA repair, environmental and human biomonitoring as well as clinical studies. Computable study for DNA damage by comet assay has generated several parameters, including Tailed Nuclei, Tail Length, % DNA in the Tail, and Tail Moment17. Dehyroepiandrosterone (DHEA) is a naturally occurring adrenal steroid in mammals synthesized from cholesterol and metabolized to androstenedione and estrogens. The decrease in its production is considered as the most characteristic age-related change in the adrenal c ortex18. DHEA has various actions, such as anti-obesity, anti-diabetic and anti-carcinogenic effects when administered to mice and rats19. However, DHEA administration effects can be a ntioxidant20 or pro-oxidant21, depending on the administered dose and specific t issue22. It was also reported that DHEA has a dose-dependent protective effect against oxidative stress-induced endothelial dysfunction in ovarictomized r ats23. Quercetin (3,5,7,30,40-pentahydroxyflavone) is considered as one of the most widely distributed flavonoids, present in fruits, vegetables, and many other dietary s ources24. This compound has been reported to have anti-atherogenic, anti-inflammatory, anti-histaminic and anti-hypertensive properties responsible for its beneficial effects against cardiovascular diseases25,26. Quercetin is an antioxidant which scavenges superoxide in ischemia–reperfusion injury27, protects against oxidative stress induced by ultraviolet light28 and inhibits angiogenesis and c arcinogenesis29,30. Moreover, quercetin has been shown to regulate the functions of hepatic stellate and Kupffer cells31. Additionally, quercetin in combination with arginine can ameliorate nano-zinc oxide nephrotoxicity in r ats32. The discovery of novel therapeutic agents against NPs’ toxicity remains a challenge. Therefore, the present study was carried out to investigate the alteration in hepatic and serum biochemical parameters and histopathological alterations induced by CuO nanoparticles in male rats and a trial to ameliorate their harmful effects by using DHEA, quercetin either alone or in combination which are well established as antioxidants to alter the oxidative damage, hepatotoxic effects of CuO-NPs. Histopathological investigatio (...truncated)