Myofibrilar functional dysregulation in fish: A new biomarker of damage to pesticides

CRUPKIN, ANDREA C.; ITURBURU, FERNANDO G.; CRUPKIN, MARCOS; MENONE, MIRTA L.

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2018 vol. 158 p. 44 - 49

0147-6513

Endosulfan (ES) modifies the ultrastructure of skeletal muscle fibers and causes changes to the swimming behavior of fish. The objectives of the present work were to evaluate, in fishes of Australoheros facetus, 1) theintegrity of myofibrils (Mf) by the analysis of SDS-PAGE profiles, and 2) the functionality of Mf through themicroscopically monitoring of the contraction and changes in Mg2+ Ca2+- ATPase and Mg2+(EGTA) -ATPaseactivities. As expected, after the addition of the contraction buffer, control fish Mf contracted. On the contrary,Mf from fish exposed at 0.5 μg/L ES showed a partial contraction and none of the fish exposed at 10 μg/L EScontracted. As judged by its high Mg2+ Ca2+ ATPase activity and low Mg2+ (EGTA) ATPase activity, control Mfshowed good functionality. In Mf from fish exposed to 0.5 and 10 μg/L ES the activities of these enzymes weresimilar, suggesting denaturation or degradation of some component of tropomyosin?troponin complex. SDSPAGE patterns of Mf from fish exposed to ES showed degradation of the myosin heavy chain and of tropomyosin.Similar values of lipid peroxidation (TBARS) were found in both control and exposed Mf, suggesting that lipidoxidation was not be related to the above-mentioned changes. The observed effects expand the knowledge of ESaction in muscles and could be used as biomarkers of damage in fishes exposed to organochlorine compoundslike the insecticide endosulfan.