Comparative bioaccumulation and effects of purified and cellular extract of cylindrospermopsin to freshwater fishHoplias malabaricus

Abstract

Many tropical freshwater ecosystems are impacted by cyanobacteria blooms increasing the risk of cyanotoxins exposure to aquatic organisms while human populations may be exposed by eating fish, drinking water, or dermal swimming. However, few toxicological data are available on the influence of cyanobacteria blooms in particular, cylindrospermopsin (CYN) on Brazilian neotropical fish. A number of studies demonstrated the ability of CYN to bioaccumulate in freshwater organisms and consequently enter the human food chain. The aim of the current study was to examine the effects of CYN following single intraperitoneal injection (50 µg/kg) of purified CYN (CYNp) or aqueous extract of CYN-producing cyanobacteria extract (CYNex) after 7 or 14 days. Biomarkers such as histopathology (liver), oxidative stress (liver and brain), and acetylcholinesterase (AChE) activity (muscle and brain) were utilized in order to assess the influence of CYN on Hoplias malabaricus. In terms of AChE activity, administration of CYNex and CYNp both muscle and brains were used as target tissues. In brain an increase of glutathione S-transferase (GST) activity and lipid peroxidation (LPO) levels was noted suggesting an imbalance in redox cycling. The majority of biomarkers did not present significant alterations in liver, but an elevation in superoxide dismutase (SOD) and glucose 6 phosphate dehydrogenase (G6PDH) activities was found. Different profiles of GST activity were observed in both studied groups (CYNex and CYNp) while LPO (CYNex and CYNp) and protein carbonylation (PCO) (CYNp) levels increased after exposure to CYN. The incidence of necrosis, melanomacrophages centers, and free melanomacrophages were detected as evidence of cell death and immune responses. Nonprotein thiols (NPT) levels were not markedly affected in both exposed groups. Data demonstrated that in vivo exposure to CYN produced biochemical and morphological disturbances in liver and brain of H. malabaricus.

Neurotoxic assessment of Microcystin-LR, cylindrospermopsin and their combination on the human neuroblastoma SH-SY5Y cell line

“…In this sense, there is only one report studying its effects in different in vitro murine cell lines (Takser et al, 2016). Meanwhile, some in vivo reports have showed in vivo neurotoxic effects in snails, tadpoles and fish, such as behavioral alterations or histopathological changes (da Silva et al, 2018;Guzmán-Guillén et al, 2015;Kinnear et al, 2007;Kiss et al, 2002;White et al, 2007).…”

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

“…Alterations in other biomarkers also have been reported in the brain of CYNexposed fish. For H. malabaricus 24 and O. niloticus, 27 both studies detected an increase in lipid peroxidation in the brain from fish exposed to different CYN sources. Such data suggest a disruption of the antioxidant defense, which can culminate in the rupture of the nuclear membrane, corroborating the DNA damage here presented.…”

“…26 For H. malabaricus, in animals exposed to a single intraperitomial injection (50 μg k −1 ) of aqueous extract of CYN-producing cyanobacteria, on average 6.79 and 5.61 ng g −1 of CYN was detected in the liver, after 7 and 14 days of exposition, respectively. 24 Histopathological biomarks also have been recorded in the liver of CYN-exposed fish, as an increase in the frequency of necrosis, melanomacrophages centers, and free melanomacrophages after 7 days of exposure. 24 In addition, an increase in the average nuclear diameter of hepatocytes, intracytoplasmic glycogen and lipid droplet accumulation, and also esteatosis were more prominent in fish intraperitoneally exposed to CYN than those exposed by gavage, sampled 5 days after the toxin administration.…”

“…24 Histopathological biomarks also have been recorded in the liver of CYN-exposed fish, as an increase in the frequency of necrosis, melanomacrophages centers, and free melanomacrophages after 7 days of exposure. 24 In addition, an increase in the average nuclear diameter of hepatocytes, intracytoplasmic glycogen and lipid droplet accumulation, and also esteatosis were more prominent in fish intraperitoneally exposed to CYN than those exposed by gavage, sampled 5 days after the toxin administration. 22 Based in such data, we assume that further studies must be developed to detect or quantify CYN in the liver of P. reticulata as well clarify the CYN mechanism of action in this organ using multiple biomarks.…”

“…[21][22][23] In the Neotropical species Hoplias malabaricus (Characiformes Order), purified CYN and its aqueous extract induced biochemical and morphological alterations after 7 and 14 exposition days in the brain and liver, as well CYN bioacumulated in these organs and also in the muscle. 24 Although in vivo studies evaluating the toxic effects of CYN are related to a few fish species, [21][22][23][24][25][26][27] they have demonstrated a broad action of CYN in several target organs. However, there are no data about the putative genotoxicity and mutagenicity caused by CYN in different tissues from fish.…”