Ex vivo and in vivo effects of arsenite on GST and ABCC2 activity and expression in the middle intestine of the rainbow trout Oncorhynchus mykiss

PAINEFILÚ, JULIO C.; PASCUAL, MARIANO M.; BIECZYNSKI, FLAVIA; LASPOUMADERES, CECILIA; GONZÁLEZ, CAROLINA; VILLANUEVA, SILVINA S.M.; LUQUET, CARLOS M.

COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. TOXICOLOGY & PHARMACOLOGY

ELSEVIER SCIENCE INC

Año: 2019 vol. 225

1532-0456

In fish of freshwaters environments, the accumulation and toxic effects of arsenite (AsIII) can be attenuated bydetoxification proteins such as GST and ABCC transporters. We studied the effects of AsIII on the middle intestineof O. mykiss in ex-vivo and in vivo/ex vivo assays. For the ex vivo assays, we measured the transport rate ofthe ABCC substrate DNP-SG and GST activity in intestinal strips and everted sacs. AsIII inhibited DNP-SG transportin a concentration-dependent manner, specifically when we applied it on the basolateral side. GST activityincreased when we applied a maximum concentration of AsIII. For the in vivo/ex vivo assays, we kept fish in waterwith or without 7.7μmolL−1 of AsIII for 48h. Then, we measured DNP-SG transport rate, GST activity, andPP1 activity in intestine strips during one hour. For PP1 activity, we incubated the strips with or without microcystin-LR (MCLR), a toxin excreted through ABCC2 proteins. We also analyzed Abcc2 and Gst-π mRNA expressionin intestine and liver tissue. In the group exposed in vivo to AsIII, DNP-SG transport rate and GST activity werehigher and the effect of MCLR over PP1 activity was attenuated. AsIII significantly induced only Abcc2 mRNAexpression in both middle intestine and liver. Our results suggest that, in the middle intestine of O. mykiss, AsIIIis absorbed mainly at the basolateral side of the enterocytes, excreted to the lumen by ABCC2 transporters, andis capable of modulating Abcc2 mRNA expression by a transcriptional mechanism.