Cerium oxide nanoparticles prevent apoptosis in primary cortical culture by stabilizing mitochondrial membrane potential.

Cerium oxide nanoparticles (CNPs) of spherical shape have unique antioxidant capacity primarily due to alternating + 3 and + 4 oxidation states and crystal defects. Several studies revealed the protective efficacies of CNPs in cells and tissues against the oxidative damage. However, its effect on mitochondrial functioning, downstream effectors of radical burst and apoptosis remains unknown. In this study, we investigated whether CNPs treatment could protect the primary cortical cells from loss of mitochondrial membrane potential (Δψm) and Δψm-dependent cell death. CNPs with spherical morphology and size range 7-10 nm were synthesized and utilized at a concentration of 25 nM on primary neuronal culture challenged with 50 μM of hydrogen peroxide (H2O2). We showed that optimal dose of CNPs minimized ROS content of the cells and also curbed related surge in cellular calcium flux. Importantly, CNPs treatment prevented apoptotic loss of cell viability. Reduction in the apoptosis could be successfully attributed to the maintenance of Δψm and restoration of major redox equivalents NADH/NAD(+) ratio and cellular ATP. These findings, therefore, suggest possible route of CNPs protective efficacies in primary cortical culture.