Vol 11, Issue 9, 2018 Online - 2455-3891 Print - 0974-2441 HARNESSING THE ANTIOXIDANT PROPERTY OF CERIUM AND YTTRIUM OXIDE NANOPARTICLES TO ENHANCE MESENCHYMAL STEM CELL PROLIFERATION HADEER A AGLAN 1,2 , MOSTAFA MABROUK 3 , RIHAM M ALY 2,4 , HANAN H BEHEREI 3 , HANAA H AHMED 1,2 * 1 Hormones Department, National Research Centre, Giza, Egypt. 2 Stem Cells Lab, Center of Excellence for Advanced Sciences, National Research Centre, Giza, Egypt. 3 Refractories, Ceramics and Building Materials Department, National Research Centre, Giza, Egypt. 4 Basic Dental Science Department, National Research Centre, Giza, Egypt. Email: hanaaomr@yahoo.com Received: 23 January 2018, Revised and Accepted: 2 August 2018 ABSTRACT Objective: This work was designed to explore if cerium oxide (CeO 2 ) and yttrium oxide (Y 2 O 3 ) nanoparticles as antioxidant agents could potentiate the proliferation of mesenchymal stem cells (MSCs) derived from human dental pulp (hDPSCs). Methods: Nanoparticles were characterized by transmission electron microscopy, particle size and zeta potential, X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscope (SEM) along with energy-dispersive X-ray spectrometry. Furthermore, MSCs were isolated from human dental pulp, propagated and characterized by flow cytometry. Thereafter, the proliferative impact of the suggested nanoparticles on hDPSCs was investigated by 3-(4,5)-dimethylthiazol)-2,5-diphenyl tetrazolium bromide assay. Results: Different sizes (14.09–26.50 nm and 18.80–31.31 nm) for CeO 2 and Y 2 O 3 respectively, morphology, charges, and proliferative efficacy in hDPSCs were recorded for both nanoparticles. Conclusion: Generally speaking, the tested nanoparticles heightened the proliferative response of hDPSCs with the most prominent effect exerted by 15 µg/ml of CeO 2 and 5 µg/ml of Y 2 O 3 . It is reasonable to assume that the antioxidant property of CeO 2 and Y 2 O 3 be involved in strengthening the proliferation process of hDPSCs. Keywords: Mesenchymal stem cells, Cerium oxide nanoparticles, Yttrium oxide nanoparticles, Antioxidant effect, Proliferative impact. INTRODUCTION The particular target of tissue engineering is to promote the repairment of the destroyed tissue and maintain its functional features [1]. Clinical usage of dental stem cells as biological progenitor candidates for tissue regeneration was recently reported [2]. However, there are many factors hinder the clinical application of mesenchymal stem cells (MSCs) such as culturing obstacles, high transformation risk, and down proliferation rate in vitro [3]. Furthermore, many studies showed some drawbacks, because of lower viability of the transplanted cells. Particularly, about 99% of implanted cells died at the 1 st h after the implantation process and this could be owed to the harshness of the human biological environment that the cells face on implantation [4,5]. One of the major causative factors for implanted cell death is oxygen deficiency due to delayed revascularization at the site of implantation [6]. Intracellular oxidative stress may be developed during the isolation of cells, multiple handling, and preparation steps of the sample as well as addition of proteolytic enzymes at reseeding stage. Earlier reports have mentioned that the increase in the intracellular reactive oxygen species (ROS) levels in the lag phase of cell growth is capable of suppressing the rate of proliferation [7]. Therefore, different approaches were intended to oppose the biological microenvironmental stress facing the cells before the transplantation procedures. Among these developed strategies is the in vitro introduction of nanoparticles rare earth oxides into MSCs cultures in order to be utilized as free radical quenchers within these cells [8]. Cerium oxide (CeO 2 ) nanoparticles, also known as nanoceria, have a great potential to scavenge superoxide anions, hydrogen peroxide, and peroxynitrite in vivo [9]. Depending on the surface oxidation state, +3/+4, nanoceria could mimic the activity of the cellular antioxidant enzymes, superoxide dismutase and catalase [10,11]. Aside from these properties, CeO 2 nanoparticles could augment angiogenesis through adjusting the intracellular oxygen environment and stabilizing hypoxia inducing factor 1α endogenously [12]. Yttrium oxide (Y 2 O 3 ), a vastly utilized host material for various rare earth dopants, is of interest for its potency to be applied in biological imaging and photodynamic therapy [13]. Y 2 O 3 has been shown to protect rat pancreatic islets from oxidative stress-mediated apoptosis [14]. Y 2 O 3 nanoparticles are well known as excellent free radical scavengers due to their non-stoichiometric crystal defects [15]. Although the therapeutic influence of CeO 2 and Y 2 O 3 nanoparticles was previously studied with different cell lines, their antioxidant and proliferative effects on the human dental pulp-derived mesenchymal stem cells (hDPSCs) in vitro have not been reported yet. The above motivations were investigated in a comparative manner between CeO 2 and Y 2 O 3 nanoparticles. It is relevant to note that different techniques such as transmission electron microscopy (TEM), particle size and zeta potential, X-ray diffraction (XRD), Fourier-transform infrared (FTIR), and scanning electron microscope (SEM) coupled with energy-dispersive X-ray spectrometry (EDX) were applied for the studied nanoparticles to demonstrate their size, morphology, potential charges, physicochemical characters, and elemental properties before conducting the in vitro assay. METHODS Nanoparticles Cerium (IV) oxide (CeO 2 ) and yttrium (III) oxide (Y 2 O 3 ) nanoparticles were purchased from Sigma-Aldrich (St Louis, Missouri, USA). Size and morphology of the nanoparticles: Transmission electron microscopy (TEM) TEM was used to analyze the crystal structure, size, and morphology of the investigated nanoparticles. Practically, TEM images were recorded © 2018 The Authors. Published by Innovare Academic Sciences Pvt Ltd. This is an open access article under the CC BY license (http://creativecommons. org/licenses/by/4. 0/) DOI: http://dx.doi.org/10.22159/ajpcr.2018.v11i9.27914 Research Article