Biotransformations, Antioxidant System Responses, and Histopathological Indexes in the Liver of Fish Exposed to Cyanobacterial Extract

Biotransformations, Antioxidant System Responses, and Histopathological Indexes in the Liver of Fish Exposed to Cyanobacterial Extract

Radiocystis fernandoi, a microcystin (MC) producer, has been common in cyanobacterial blooms in tropical regions. Microcystin is a hepatotoxin that causes tissue damage and even death in animals, including humans; its detoxification process may involve biotransformation and activation of the antioxi...

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Published in:Environmental toxicology and chemistry Vol. 39; no. 5; pp. 1041 - 1051
Main Authors: Paulino, Marcelo Gustavo, Tavares, Driele, Terezan, Ana Paula, Sakuragui, Marise Margareth, Pesenti, Emanuele, Giani, Alessandra, Cestari, Marta Margareth, Fernandes, João Batista, Fernandes, Marisa Narciso
Format: Journal Article
Language:English
Published: United States Blackwell Publishing Ltd 01-05-2020
Subjects:
Antioxidants
Biotransformation
Carbonyl compounds
Carbonyls
Catalase
Cyanobacterium
Damage
Deoxyribonucleic acid
Detoxification
DNA
DNA damage
Exposure
Fibrosis
Glutathione
Glutathione peroxidase
Hepatotoxicity
Lipid peroxidation
Lipids
Liver
Liver diseases
Melanomacrophage
Microcystins
Oxidative stress
Peroxidase
Peroxidation
Proteins
Radiocystis fernandoi
Recovery of function
Superoxide dismutase
Tropical environment
Tropical environments
Tropical fish
Radiocystis fernandoi
Melanomacrophage
Oxidative stress
Cyanobacterium
DNA damage
Fibrosis
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Summary:Radiocystis fernandoi, a microcystin (MC) producer, has been common in cyanobacterial blooms in tropical regions. Microcystin is a hepatotoxin that causes tissue damage and even death in animals, including humans; its detoxification process may involve biotransformation and activation of the antioxidant defense system. We evaluated the detoxification pathway, examined the antioxidant defense system responses, and determined the alterations and the organ histopathological indexes in the liver of the tropical fish Hoplias malabaricus after acute and subchronic intraperitoneal exposure to microcystin. The crude microcystin extract of R. fernandoi had predominantly MC‐RR and MC‐YR. The detoxification process was activated by increasing ethoxyresorufin‐O‐deethylase activity, whereas glutathione S‐transferase was inhibited. The activity of the antioxidant defense enzymes superoxide dismutase (SOD) and glutathione peroxidase decreased after acute exposure; the SOD–catalase system and the glutathione level increased after subchronic exposure. The carbonyl protein level, lipid peroxidation (LPO), and DNA damage were unchanged after acute exposure, whereas protein carbonyl was unchanged, LPO decreased, and DNA damage increased after subchronic exposure. Histopathological alteration indexes differed between acute and subchronic exposure, but the histopathological organ indexes indicate liver dysfunction in both exposure periods. We conclude that MC‐RR and MC‐YR induce different liver responses depending on the time of exposure, and the antioxidant defense responses after subchronic exposure may help to partially restore the liver function. Environ Toxicol Chem 2020;39:1041–1051. © 2020 SETAC Crude extract of Radiocystis fernandoi content microcystins alters the biotransformation and the antioxidant system defense enzyme activity and induces liver histopathologies after acute and subchronic exposure. Abc = ATP‐binding cassette; CAT = catalase; EROD = ethoxyresorufin‐O‐deethylase; GPX = glutathione peroxidase; GR = glutathione reductase; GSH = glutathione; GSSG = glutathione disulfide; GST = glutathione S‐transferase; LPO = lipid peroxidation; LOH = lipid alcohol; MC = microcystin; Oatp = organic anion transporter polypeptide; SOD = superoxide dismutase.
ISSN:0730-7268
1552-8618
DOI:10.1002/etc.4696