Effect of temperature on the toxicokinetics and gene expression of the pacific cupped oyster Crassostrea gigas exposed to cadmium

In this study, we investigated the influence of temperature on the bioaccumulation and depuration of Crassostrea gigas exposed to Cd associated with its molecular responses. Oysters were acclimatized to different temperatures (10 degrees C, 15 degrees C, 20 degrees C, 25 degrees C, and 30 degrees C) for 14 d and then exposed to 10 mu g/L Cd for 28 d, followed by a depuration period of 35 d. Oysters were sampled for chemical analysis by inductively coupled plasma mass spectrometry (ICP-MS) and for mRNA quantification by qPCR. In the digestive gland, gill, and mantle, the cadmium concentration at 10 degrees C was significantly lower than that at 25 degrees C and 30 degrees C in both the whole experiments. The use of a two-compartment model showed that the uptake rate k 1 in the above three tissues increased with increasing temperatures ranging from 15 to 25 degrees C. The fastest elimination rates and shortest half-lives were observed at 15-25 degrees C. The induction of metallothionein (MT) only occurred in the digestive gland at 15 degrees C and 20 degrees C at the end of the accumulation phase. In the mantle and gills, the expression of P-glycoprotein (P-gp) was significantly induced at the end of the accumulation phase and significantly inhibited at the end of the depuration phase. In the digestive gland, the expression of P-gp was induced at the end of both the accumulation and depuration phases. Heat shock protein (hsp70) expression exhibited an overall increasing trend throughout the experiment.