Characterisation of the multixenobiotic resistance (MXR) mechanism in the freshwater snail Physa acuta from Patagonia (Argentina)

Abstract

P-glycoprotein (P-gp) mediated multixenobiotic resistance (MXR) is a mechanism analogous to multidrug resistance (MDR), which has been extensively characterised in mammalian tumours. The expression and function of the MXR mechanism has been demonstrated in numerous aquatic organisms and has been proposed as a biomarker for pollution assessment. The purpose of this study was to evaluate the activity and expression of the MXR mechanism in freshwater snails (Physa acuta) of the Andean–Patagonian region. The accumulation and efflux rates of the model P-gp substrate Rhodamine B in snails previously exposed to pollution were measured. Results confirmed that MXR activity decreased after maintenance in clean water, and that a depuration period of 7 d was long enough to observe a significant deinduction of this system. The results demonstrate the presence of a P-gp-like transport system in the freshwater snail P. acuta from Patagonia, and suggest its function as a defence system. The results of this study could be used to provide information on the possible use of these snails as bioindicators in toxicological testing.