DOWN-REGULATION OF MULTIDRUG RESISTANCE-ASSOCIATED PROTEIN 2 (MRP2) BY LONG-TERM OXIDATIVE STRESS IN A MODEL OF HUMAN INTESTINAL EPITHELIUM AND BENEFICIAL EFFECT OF N-ACETYL-L-CYSTEINE (NAC)

RICARDI, LAURA; ZECCHINATI, FELIPE; ARANA, MAITE ROCÍO; PERDOMO, VIRGINIA GABRIELA; GARCÍA, FABIANA; VILLANUEVA, SILVINA STELLA MARIS

Buenos Aires

Congreso; SOCIEDAD ARGENTINA DE FISIOLOGÍA (SAFIS) 2023; 2023

Introduction: Oxidative stress (OS) produced by continuous exposure to dietary additives and contaminants, is a key factor in the development of gastrointestinal disorders, in which the intestinal barrier is altered. Post-translational down-regulation of rat Mrp2, an essential component of the intestinal transcellular barrier in the disposition of environmental toxicants and therapeutic drugs, by short-term OS, was recently demonstrated. N-acetylcysteine (NAC) is a potent antioxidant, which exerts its effect as GSH precursor and effective ROS scavenger. Objectives: To evaluate the long-term effect of OS on the expression and activity of human MRP2 by TBH 250 µM and its prevention by NAC 1mM, as well as the probable molecular underlying pathway, in Caco-2 cell. Methods: MRP2 expression was evaluated by western blot in total cell membranes and plasma membranes (PM). Real time RTq-PCR was performed for evaluate changes in RNAm expression. MRP2 activity was determined by quantifying the efflux of dinitrophenyl-S-glutathione into the incubation medium by HPLC, using 1-chloro-2,4-dinitrobenzene 100 µM as precursor substrate. Statistical analyses were performed using one-way ANOVA followed by the post hoc Tukey-test and results expressed as a % difference with respect to control (C). Results: We confirmed that TBH generated OS at 24 h, as indicated by increased lipid peroxidation end products (+140%) and reduced SOD activity (-29%) (p