Protective Effect of Prolactin against Methylmercury-Induced Mutagenicity and Cytotoxicity on Human Lymphocytes

Mercury exhibits cytotoxic and mutagenic properties as a result of its effect on tubulin. This toxicity mechanism is related to the production of free radicals that can cause DNA damage. Methylmercury (MeHg) is one of the most toxic of the mercury compounds. It accumulates in the aquatic food chain, eventually reaching the human diet. Several studies have demonstrated that prolactin (PRL) may be differently affected by inorganic and organic mercury based on interference with various neurotransmitters involved in the regulation of PRL secretion. This study evaluated the cytoprotective effect of PRL on human lymphocytes exposed to MeHg in vitro, including observation of the kinetics of HL-60 cells (an acute myeloid leukemia lineage) treated with MeHg and PRL at different concentrations, with both treatments with the individual compounds and combined treatments. All treatments with MeHg produced a significant increase in the frequency of chromatid gaps, however, no significant difference was observed in the chromosomal breaks with any treatment. A dose-dependent increase in the mitotic index was observed for treatments with PRL, which also acts as a co-mitogenic factor, regulating proliferation by modulating the expression of genes that are essential for cell cycle progression and cytoskeleton organization. These properties contribute to the protective action of PRL against the cytotoxic and mutagenic effects of MeHg.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)IFPA Itaituba, Fed Inst Educ Sci & Technol Para, BR-68180000 Campinas, Para, BrazilFed Univ Para, Inst Biol Sci, BR-66075110 Belem, Para, BrazilIFPA, Educ Fed Inst Sci & Technol Para, BR-66645240 Belem, Para, BrazilUniv Para, Ctr Biol & Hlth Sci, BR-66050540 Belem, Para, BrazilFed Univ Western Para, UFOPA, BR-68040470 Santarem, Para, BrazilUniversidade Federal de São Paulo, Dept Morphol & Genet, BR-04021001 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Morphol & Genet, BR-04021001 São Paulo, BrazilWeb of Scienc