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.

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“…The possible action of organic and inorganic effluent components on the normal functioning of the central nervous system can explain the diversity of herein observed behavioral effects. According to Souza et al (2016a), variables such as sex, age, effluent type (derived from different bovine skin processing stages), rodent species and lines and effluent concentration, are important factors contributing to different results.…”

“…Murine experimental models can help in understanding the effects of contact with tannery effluent on the central nervous system, since clinical neurobehavioral research involving tannery workers is almost nonexistent. Some studies simulated tannery effluent exposure in an animal-analysis laboratory environment in order to assess the intake of water contaminated with tannery effluent (Siqueira et al, 2011;Moysés et al, 2014;Souza et al, 2016a;2016b;Guimarães et al, 2016a;2016b;Rabelo et al, 2016;Guimarães et al, 2017). However, these studies are incipient when it comes to the effects of dermal tannery effluent on laboratory animals.…”

Behavioral changes in female Swiss mice exposed to tannery effluents

“…In Souza et al (2016), moderate hydropic degeneration was detected in animals (C57Bl/6J mice) exposed to tannery effluents, mainly in the periportal space. A large number of necrotic hepatocytes were detected, especially in animals exposed to higher tannery effluent concentrations.…”

“…Only a few authors have evaluated the effect of tannery effluents on mammals, among which are Kumar et al (2008), Siqueira et al (2011), Moysés et al (2014, Silva et al (2015), Lemos et al (2015), Ferreira et al (2015), Souza et al (2016) and Rabelo et al (2016). In the pioneering study by Kumar et al (2008), chronically exposing male Wistar rats to tannery effluent, the authors observed a mass increase of all of the androgen-dependent organs evaluated, such as the prostate and seminal vesicle, and found deformations in the seminiferous tubules with testicular hyperplasia signals.…”