Abstract 379: Protective Effect of Ceria Nanoparticle on Focal Cerebral Ischemia in Rats

Abstract

Background and Objectives Ceria, one of the rare earth resources, is a potent catalytic agent using in many industrial fields. Interestingly, after converting ceria into biocompatible nanoparticle via chemical engineering, ceria nanoparticle may be used as anti-oxidant agent to treat diseases related to oxidative injuries. However, few studies have elaborated on the association between ceria nanoparticle and ischemia-reperfusion injury in experimental stroke model. Methods We used 3 nm ceria nanoparticle via the combining process using thermal decomposition and reverse micelle method. To make biocompatible, ceria nanoparticle was coated with phospholipids-PEG. We induced ischemia-reperfusion injury in SD rats via modified Longa method, and ceria nanoparticle or PBS was administered intravenously. Infarct volume and the number of apoptotic cells (TUNEL-positive cells) were measured at 24 hours. To identify the anti-oxidant role of ceria nanoparticle, hydroethidine, a marker of superoxide activity, was administered 15 minutes before inducing focal ischemia, and detect ethidine, the product of reaction between superoxide and hydroethidine, using fluorescent microscopy at 3 hours. Results We compared three doses of ceria nanoparticle and the infarct volumes were decreased dose-dependently (ρ = -0.39, p < 0.05). The infarct volumes were 130.8 mm3 in ceria-treated group (0.5 mg/kg) and 236.2 mm3 in control group (p < 0.05). The ceria-treated group exhibited a lower number of TUNEL-positive apoptotic cells (ceria-treated group: 32.5 ± 18.3 cells/mm3 ; control group: 63.4 ± 2.4 cell/mm3; p < 0.05). Ethidine (oxidezed hydroethidine) signals were weakly observed in the ischemic cortices of ceria-treated rats compared to control group. Conclusion Our study documented that ischemia-reperfusion injury was decreased by ceria nanoparticle via superoxide scavenging effects. This result may indicate the potentially protective effect of ceria nanoparticle on ischemic stroke.