Differential Activities of Glutathione S-Transferase Isoenzymes in Strains of Fasciola Hepatica Susceptible and Resistant to Triclabendazole

Fasciolosis, a parasitic zoonosis of intrahepatic location, is caused by the trematode Fasciola hepatica. Its control is mainly based on the use of the anthelminthic Triclabendazole (TCBZ). The indiscriminate use of this drug has favored the development of anthelmintic resistance. The Glutation S-Transferases (GSTs) are multifunctional enzymes involved in the detoxification of xenobiotics and endogenous compounds using conjugation with endogenous glutathione. Recently, it has been shown an active participation of this family of enzymes in the detoxification of TCBZ related to the phenomenon of resistance. In F. hepatica, eight isoenzymes of the GST are present. Since it is well known that different isoenzymes do not necessarily have the same metabolic activity, this study evaluated the cytosolic activity of mu and pi GST isoenzymes in TCBZ resistant (Sligo and Oberon strains) and TCBZ susceptible (Cullompton strains) of F. hepatica. The results obtained in this study confirm that, although both isoenzymes are involved in different processes of detoxification in F. hepatica, only the GSTmu isoenzyme is involved in the manifestation of resistance to TCBZ.