Effect of Ce(III) on Heat Production of Mitochondria Isolated from Hybrid Rice

The effect of cerium on mitochondria isolated from hybrid rice Shanyou 63 (Oryza sativa L) was investigated. Through in vivo culture, low dose Ce³⁺ promoted, but higher dose Ce³⁺, restrained mitochondrial heat production. However, through vitro incubation, Ce³⁺ showed only inhibitory action on mitochondrial energy turnover, the concentration required for 50% inhibition being 46.7 μM. In addition, Ce³⁺, like Ca²⁺, induced rice mitochondrial swelling and decreased membrane potential (△ψ), which was inhibited by the specific permeability transition inhibitor cyclosporine A (CsA). The induction approached a constant level while mitochondrial metabolism was fully prevented by Ce³⁺. These results demonstrated that cerium influenced rice mitochondria in vivo and in vitro via different action pathways, and the latter involved the opening of rice mitochondrial permeability.