Histopathological findings on Carassius auratus hepatopancreas upon exposure to acrylamide: correlation with genotoxicity and metabolic alterations

Abstract

Acrylamide is an amide used in several industrial applications making it easily discharged to aquatic ecosystems. The toxicity of acrylamide to aquatic organisms is scarcely known, although previous studies with murine models provided evidence for deleterious effects. To assess the effects of acrylamide to freshwater fish, goldfish (Carassius auratus L.) were exposed to several concentrations of waterborne acrylamide and analysed for genotoxic damage, alterations to detoxifying enzymes and histopathology. Results revealed a dose-dependent increase in total DNA strand breakage, the formation of erythrocytic nuclear abnormalities and in the levels of hepatic cytochrome P4501A (CYP1A) and glutathione S-transferase (GST) activity. In addition, acrylamide induced more histopathological changes to pancreatic acini than to the hepatic parenchyma, regardless of exposure concentration, whereas hepatic tissue only endured significant alterations at higher concentrations of exposure. Thus, results confirm the genotoxic potential of acrylamide to fish and its ability to induce CYP1A, probably as a direct primary defence mechanism. This strongly suggests the substance's pro-mutagenic potential in fish, similarly to what is known for rodents. However, the deleterious effects observed in the pancreatic acini, more severe than in the liver, could indicate a specific, albeit unknown toxic mechanism of acrylamide to fish that overran the organism's metabolic defences against a chemical agent rather than causing a general systemic failure.

Toxicity Evaluation of Acrylamide on the Early Life Stages of the Zebrafish Embryos (<i>Danio rerio</i>)

“…Acrylamide toxicity study conducted in two species of aquatic macroinvertebrates and three species of fish demonstrated that acrylamide was moderately toxic aquatic organisms [14]. There was also histopathological changes and correlation with genotoxicity and metabolic alterations when Carassius auratus hepatopancreas (goldfish) was exposed to acrylamide [15].…”

Acrylamide induces locomotor defects and degeneration of dopamine neurons in Caenorhabditis elegans

“…Multiple adverse effects of acrylamide have been demonstrated, including reproductive toxicity, carcinogenicity and neurotoxicity (Hasegawa et al, 2004;Walters et al, 2014;Xu et al, 2014). Acrylamide can induce litter size, DNA strand breaks and lethal mutations (Larguinho et al, 2014;Tyl et al, 2000;Wang et al, 2010). Previous studies have shown the carcinogenic effects of acrylamide in experimental animals (Ao & Cao, 2012;Bull et al, 1984;Friedman et al, 1995).…”

Acrylamide in Surface and Drinking Water

“…Toxicity studies have revealed moderate to low effects of acrylamide monomers to aquatic wildlife, especially to fish and crustaceans [55][56][57]. Environmentally relevant chronic, sublethal doses of anionic polymer products to juvenile rainbow trout resulted in either no damage or very low levels of damage to gill tissue.…”

“…Acrylamide has been shown to cause severe pancreatic tissue lesions in goldfish, which added a most probable effect as a genotoxicant and probable mutagenic agent in fish [57]. Another study with goldfish demonstrated that acrylamide is genotoxic in blood erythrocytes; this leads to cancer in individuals, and also disrupts homeostasis of organisms and introduces genetic diversity [60].…”

“…Nonetheless, sublethal exposure to acrylamide in goldfish is genotoxic and toxic to both the liver and pancreas [57]. According to studies, acrylamide in aquatic ecosystems was reported in micrograms per liter and scaled up to a few milligrams per liter in sewage effluent.…”