Pre-treatment with mild metal exposure suppresses the neurotoxicity on locomotion behavior induced by the subsequent severe metal exposure in Caenorhabditis elegans

Adaptive response to neurotoxicity on locomotion behavior by severe metal exposure was investigated in Caenorhabditis elegans. Exposure to 2.5 μM of metals induced a moderate but significant reduction of locomotion behavior and induction of hsp-16.2::gfp expression. After pre-exposure to 2.5 μM of metals, the reduced locomotion behavior induced by subsequent 50 and 100 μM of metal exposure were significantly prevented, and the induction of hsp-16.2::gfp expression caused by subsequent 50 and 100 μM of metal exposure were significantly suppressed. In contrast, after pre-exposure to 50 μM examined metals, the reduced locomotion behavior induced by subsequent 50 and 100 μM metal exposure were further decreased, and the noticeable induction of hsp-16.2::gfp expression caused by subsequent severe metal exposure were further enhanced. Therefore, pre-treatment with mild metal exposure can activate the adaptive response to neurotoxicity on locomotion behavior induced by subsequent severe metal exposure in nematodes.