| Summary: | 碩士 === 國立臺灣大學 === 動物學研究所 === 99 === Cadmium (Cd), a heavy metal commonly exists in environmental soil. Bioaccumulation of Cd causes systemic toxicity to most animals in the world. Earthworms have been recognized as suitable bio-indicator to evaluate soil pollution after exposure to heavy metals. In this study, Eisenia andrei was used as the animal model to study Cd-induced toxic response. Cd accumulation and mortality showed a dose-dependent and time-dependent in earthworms. After Cd exposure, earthworms showed several pathological phenomena including skin wrinkle, partial hyperemia, blood effusion, bleaching and abnormal body wall collapse. Cd-exposed earthworms showed higher H2O2 concentration and lower catalase activity. In addition, earthworms treated with various antioxidants (EUK134, curcumin, rosmarinic acid, catechin, or vitamin C) decreased both Cd accumulation and mortality. Furthermore, the collapse part of earthworms showed higher Cd accumulation than the non-collapse part in Cd-exposed earthworm, and body wall collapse usually occurred at the posterior part of earthworm. Nevertheless, cells underwent both apoptosis and necrosis at collapsed part. This may inferr that body wall collapse represent a detoxification mechanism in Cd-exposed earthworms.
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