Histopathological assessment of C57Bl/J mice organs exposed to tannery effluents

Abstract

The effluent produced in tanneries can cause environmental damage and public health problems when disposed of improperly. However, few toxicological studies have evaluated the effects of the intake of tannery wastewater by mammals. The objective of this study is the histological assessment of organs of C57Bl/J mice exposed to the intake of different concentrations of raw tannery effluents, beginning with the hypothesis that these effluents can cause damage to the histological structure of the organs. The animals were divided into the following groups: control (0% effluent) and exposed to 0.1%, 1%, and 5% raw tannery effluent diluted in water, for a period of 120 days. For the histopathological evaluations, samples of the liver, kidney, spleen, heart, and lung were collected, fixed, and stained by the hematoxylin and eosin staining techniques. No anomalies were observed in kidney, spleen, heart, and lung fragments. Alterations were observed only in liver fragments. Moderate hydropic degeneration was detected in animals exposed to tannery effluents, mainly in the periportal space. A large number of necrotic hepatocytes (p<0.05) were detected, especially in animals exposed to higher tannery effluent concentrations. Further, the largest number of hepatocytes with karyomegaly (p<0.05) was observed in animals exposed to the highest effluent concentrations. Our study suggests that the observed alterations are related to the intake of tannery effluents and that these effluents cause changes that lead to an increase of free radical production and direct aggressions to hepatocyte membranes as well as to the appearance of hepatocellular karyomegaly.