Hormetic Effects of Cerium, Lanthanum and Their Combination at Sub-micromolar Concentrations in Sea Urchin Sperm

Abstract

Rare earth elements (REEs) cerium (Ce) and lanthanum (La) and their combination were tested across a concentration range, from toxic (10−4 to 10−5 M) to lower concentrations (10−6 to 10−8 M) for their effects on sea urchin (Sphaerechinus granularis) sperm. A significantly decreased fertilization rate (FR) was found for sperm exposed to 10−5 M Ce, La and their combination, opposed to a significant increase of FR following 10−7 and 10−8 M REE sperm exposure. The offspring of REE-exposed sperm showed significantly increased developmental defects following sperm exposure to 10−5 M REEs vs. untreated controls, while exposure to 10−7 and 10−8 M REEs resulted in significantly decreased rates of developmental defects. Both of observed effects–on sperm fertilization success and on offspring quality–were closely exerted by Ce or La or their combination.