J.A.N. Monteiro, L.A. Cunha, R.C. Silva, J.J.S. Freitas, R.C.S. Conceição, S.S.C. Lima, D.D.F.A. Alcântara, R.M.R. Burbano and C.A.M. Rocha
Published April 20 2024
Genet. Mol. Res. 23 (2): gmr19267
DOI http://dx.doi.org/10.4238/gmr19267

About the authors
J.A.N. Monteiro, L.A. Cunha, R.C. Silva, J.J.S. Freitas, R.C.S. Conceição, S.S.C. Lima, D.D.F.A. Alcântara, R.M.R. Burbano and C.A.M. Rocha

Corresponding author
J.A.N. Monteiro
E-mail: augustomonteiro23@hotmail.com

ABSTRACT

Most riverside communities consume large quantities of fish as a part of their diet, increasing the risk of mercury exposure in polluted areas. The potential protective role of prolactin (PRL) against the toxic action of methylmercury (MeHg) was investigated in the fish Geophagus brasiliensis using the micronucleus test and analyzing lipid peroxidation, catalase (CAT) and glutathione peroxidase (GPx) levels. G. brasiliensis is endemic to Brazil, very resistant, important as an aquarium fish, and also used as human food. Fish were acquired commercially and divided into three groups of six animals each: 1) NC: Negative Control; 2) MeHg: exposure to 0.5 mg/L MeHg via water; and 3) MeHg/PRL: exposure to 0.5 mg/L MeHg and treated with 250 μg/kg PRL every 12h. The treatments lasted 5 days. There was a highly significant increase in the formation of micronuclei (MN) and erythrocyte nuclear abnormalities (ENA) in the MeHg group compared to the NC group, but when PRLwas administered (MeHg/PRL group), the numbers of MN and ENA were reduced. The TBARS results did not differ significantly between the tested groups. CAT levels were significantly reduced in the treated groups compared to the NC group. GPx levels showed a very significant increase in the MeHg group in relation to the NC group, and in the MeHg/PRL group, there was a significant decrease, although it did not reach the same values as those in the NC group. Although the role of prolactin in protecting against oxidative stress has not been elucidated, the protective effect of prolactin against the mutagenic effects of mercury has been very well demonstrated. To the best of our knowledge, this is the first demonstration of the protective effect of prolactin against mercury-induced mutagenicity in fish.

Key words: Geophagus brasiliensis; Mercury; Micronuclei; Oxidative stress; Prolactin