Cylindrospermopsin-Microcystin-LR Combinations May Induce Genotoxic and Histopathological Damage in Rats

Abstract

Cylindrospermopsin (CYN) and microcystins (MC) are cyanotoxins that can occur simultaneously in contaminated water and food. CYN/MC-LR mixtures previously investigated in vitro showed an induction of micronucleus (MN) formation only in the presence of the metabolic fraction S9. When this is the case, the European Food Safety Authority recommends a follow up to in vivo testing. Thus, rats were orally exposed to 7.5 + 75, 23.7 + 237, and 75 + 750 μg CYN/MC-LR/kg body weight (b.w.). The MN test in bone marrow was performed, and the standard and modified comet assays were carried out to measure DNA strand breaks or oxidative DNA damage in stomach, liver, and blood cells. The results revealed an increase in MN formation in bone marrow, at all the assayed doses. However, no DNA strand breaks nor oxidative DNA damage were induced, as shown in the comet assays. The histopathological study indicated alterations only in the highest dose group. Liver was the target organ showing fatty degeneration and necrotic hepatocytes in centrilobular areas, as well as a light mononuclear inflammatory periportal infiltrate. Additionally, the stomach had flaking epithelium and mild necrosis of epithelial cells. Therefore, the combined exposure to cyanotoxins may induce genotoxic and histopathological damage in vivo.

In Vivo Genotoxicity Evaluation of a Stilbene Extract Prior to Its Use as a Natural Additive: A Combination of the Micronucleus Test and the Comet Assay

“…Furthermore, it was performed in a limited number of animals complying with the 3Rs principles (Replace, Reduce, and Refine) [ 27 ]. Moreover, our group has previous experience performing the MN as well as comet assay simultaneously to detect the genotoxic effects of different substances in rats [ 28 , 29 , 30 ]. This evaluation was completed with a detailed analytical study to ensure that ST-99 extract effectively reached the studied tissue.…”

New Data on Cylindrospermopsin Toxicity

“…This result suggests that intestinal epithelial cells, cells which are continuously dividing, are very sensitive to CYN. The presence of CYN, especially if it is in combination with another toxin [ 10 ] or an environmental factor that causes stress, may induce pathological changes in the human gastrointestinal tract. Moreover, the intestinal epithelial layer is located on the mucosal border and for this reason it is not as well protected by the body homeostasis as the inner tissues.…”

“…CYN is a stable tricyclic quinidine alkaloid, whose presence in freshwater pools often increases [ 10 ] due to eutrophication and seasonal dynamics. CYN has been classified mainly as a hepatotoxin [ 11 ].…”

Genotoxicity Evaluation of Propyl-Propane-Thiosulfinate (PTS) from Allium genus Essential Oils by a Combination of Micronucleus and Comet Assays in Rats

“…The MN test was performed according to the OECD guideline 474 [ 27 ] and Diez-Quijada et al [ 33 ]. The bone marrow of the femurs of the rats were mixed with a drop of fetal bovine serum.…”