DNA damage induced by cylindrospermopsin on different tissues of the biomonitor fish Poecilia reticulata

Abstract

The cyanotoxin cylindrospermopsin (CYN) is the second biggest cause of poisoning worldwide, both in humans and animals. Although CYN primarily affects the aquatic environments and can be absorbed in fishes by multiple routes, data reporting its toxicity and mechanism of action are still scarce in this group. Using P. reticulata as model species, it was evaluated whether CYN promotes mutagenic and genotoxic effects in different fish target tissues. Adult females were exposed in a static way to 0 (control), 0.5, 1.0, and 1.5 μg L −1 of pure CYN for 24 and 96 hours. For the first time, DNA damage was detected in fish brain after CYN exposition. In brain cells, a concentrationresponse DNA damage was observed for both exposure times, suggesting a direct or indirect action of CYN in neurotoxicity. For the liver cells, 96 hours caused an increase in DNA damage, as well the highest percentage of DNA in the tail was reached when used 1.5 μg L −1 of CYN. In peripheral blood cells, an increase in DNA damage was observed for all tested concentrations after 96 hours. In erythrocytes, micronuclei frequency was higher at 1.5 μg L −1 treatment while the erythrocyte nuclear abnormalities (ENA) frequency was significantly higher even at the lowest CYN concentration. Such data demonstrated that acute exposition to CYN promotes genotoxicity in the brain, liver, and blood cells of P. reticulata, as well mutagenicity in erythrocytes. It rises an alert regarding to the toxic effects of CYN for aquatic organisms as well as for human health.

Cytotoxicity and Effects on the Synapsis Induced by Pure Cylindrospermopsin in an E17 Embryonic Murine Primary Neuronal Culture in a Concentration- and Time-Dependent Manner

“…Thus, both markers were used not only to study viability but also to confirm that the cells under study were specifically neurons. For this purpose, primary neuronal cultures were exposed to different concentrations of CYN (0.25-1 µg/mL) for different durations (12,24, and 48 h), and the number of neurons was quantified by MAP2 and NeuN immunocytochemistry. As shown in Figure 1, a significant decrease in neuronal viability was observed after 48 h of exposure for all concentrations of CYN assayed and after 24 h of exposure only for the highest concentration (1 µg/mL CYN).…”

“…Moreover, CYN induced significant inhibition of AChE activity and increased LPO levels, as well as relevant histopathological alterations in the brain of fish subchronically exposed to the toxin [ 22 ]. Thus, CYN has been demonstrated to be able to cross the blood–brain barrier, as its presence has been detected in the brain of at least three different fish species [ 22 , 23 , 24 ]. In mice that were subchronically orally exposed to purified CYN (75–300 μg/kg/d) for 90 days, toxicity was noted at all dose levels tested [ 25 ].…”

“…The main mechanism of action of CYN is protein synthesis inhibition, including the synthesis of the tripeptide glutathione (GSH), which leads to oxidative stress, which, in turn, leads to increased lipid peroxidation, DNA damage, and apoptosis [ 7 , 20 , 24 , 27 , 28 , 29 , 30 ]. However, the neurotoxic effects of this cyanotoxin have been poorly studied so far, with previous reports mainly demonstrating apoptosis, oxidative stress, and alteration of acetylcholinesterase activity, but no studies have focused on neuronal function [ 19 , 31 ].…”

Co‐exposure of iron oxide nanoparticles and glyphosate‐based herbicide promote liver toxicity in guppy (Poecilia reticulata): A histochemical and ultrastructural approach

“…[20][21][22] In order to know the metabolic responses in fish exposed to xenobiotics, it is recommended to consider the relevance of using the species P. reticulata (guppy) as a biomonitor for ecotoxicological studies. 23,24 In addition to being a suitable animal for laboratory experiments due to its easy maintenance, it exhibits sensitivity and rapid responses to exposure, furthermore, the Organization for Cooperation and Development (OECD) and the American Public Health Association recommend this species for experimental studies.…”