Abstract

Ultrathin sections of muscular and hepatic tissues of Hoplias malabarícus from contaminated and non-contaminated areas by mercury were compared in order to observe histological and ultrastrutural perturbations, under transmission electrón microscopy (Zeiss 900 Electrón Microscope). The hepatocytes of control site (Cima Lake) showed endoplasmic reticulum, mitochondria and nucleus with classical morphological aspects and cytoplasm distribution. However, the hepatocytes of contaminated area (Campelo Lake) showed altered mitochondria distribution with morphological change in the mitochondria! cristae. Therefore the endoplasmic reticulum elements were dilated. The muscular tissue of ftsh from Cima Lake showed a symmetric and parallel miofibrils distribution with defined sarcomeres. The contaminated samples of Campelo Lake developed lárge lysed areas, myofibrils disruption, discontinued I band and undefined sarcoplasm. Our results strongly suggest that mercury contamination observed in Hoplias malabarícus caused hepatic and muscular alterations.