In vitro and in vivo effects of sublethal cadmium on the expression of MT2 and ABCC2 genes in grass carp (Ctenopharyngodon idellus)

Abstract

To gain more knowledge about the physiological regulation of metal pollutant detoxification in grass carp, we examined Cd concentration and its the potential influence on the expression of metallothionein 2 (MT2) and multidrug resistance protein 2 (ABCC2) mRNA in the liver and kidney, using in vitro and in vivo experiments. First, the full-length of MT2 cDNA and partial ABCC2 cDNA was obtained, consisting 183bp and 366bp respectively. In vivo approach, grass carp received 96h exposure of Cd (1/10 LD50), and MT2 and ABCC2 mRNA expression were determined by qRT-PCR. The Cd treatment resulted in an increase of MT2 mRNA level in the liver with Cd accumulation. Nonetheless, the elevation ABCC2 mRNA in the liver was appeared at 48h after Cd exposure, as well as the expression of MT2 and ABCC2 mRNA in the kidney. The in vitro experiment was carried out using the hepatocyte (L86) and nephroblasts (CIK). The qRT-RCR results showed that MT2 and ABCC2 mRNA dramatically increased following Cd exposure (1/10 LD50); however, ABCC2 mRNA expression was suppressed in the L86 cell line at first (6h). In conclusion, this result suggested that both MT2 and ABCC2 mRNA may play important roles in the detoxification of toxic metals, and MT2 gene was more sensitive to Cd induction.

Keywords: ABCC2 gene; Cadmium; Detoxification mechanism; Grass carp; MT2 gene.