Histopathological and ultrastructural changes in the gills of Poecilia reticulatus induced by an organochlorine pesticide.

After exposure to 1.2-3.0 ppb of DDT in an aquatic-terrestrial model ecosystem, the gills of guppies showed histopathological changes when examined by light and electron microscopy. The secondary lamellae of the gills were shortened and deformed and the epithelial cells were disoriented with regard to the pillar cell system. In many places erythrocytes were virtually absent from the blood laguna, which was filled with the flanges of pillar cells. The microfilament bundles in the pillar cell cytoplasm had disintegrated. The chloride cells were swollen and alterations had occurred in their mitochondria and nuclei. The changes did not resemble the typical non-specific pattern of pesticide poisoning, and were probably specific to DDT.