To better understand the toxicity of tetrabromobisphenol A (TBBPA), its effects on the model nematode Caenorhabditis elegans were investigated. Following a step and repeated chronic exposure from L4-larvae to
day-10 adult, physiology endpoints (growth and locomotion behaviors including head thrashes, body bends and pumping rate), biochemical endpoints (reactive oxygen species, superoxide dismutase activity, catalase activity), and molecular stress-related gene expression were tested at environmentally relevant concentrations of TBBPA (0.01-100g/L). The results showed that concentrations of TBBPA greater than 10g/L, clearly influenced the physiology behaviors (growth and locomotion endpoints). Under repeated exposure, C. elegans exhibited adaptive responses in head thrashes and pumping rate. Compared to toxicity evaluation following repeated chronic exposure, a significantly greater response was induced at the same concentration following a step chronic exposure. Reactive oxygen species production was significantly enhanced following a step and repeated TBBPA exposure at the concentrations of 1 and 10g/L, respectively. qRT-PCR showed that
ctl-1,
ctl-2,
ctl-3 and
sod-3 expression significantly increased, which was obviously correlated with physiological and biochemical behaviors under both treatment conditions according to Pearson correlation test analysis.
sod-3 and
ctl-2 mutations were more sensitive than the wild-type N2 under a step chronic TBBPA exposure at a level of 10g/L. Thus, chronic exposure to TBBPA induces an oxidative stress response in C. elegans, with
ctl-2 and
sod-3 playing a vital role in TBBPA-induced toxicity in nematodes.