Oxidative Damage in Human Periodontal Ligament Fibroblast (hPLF) after Methylmercury Exposure.

Autor: Nogueira LS; Universidade Federal do Pará, Laboratório de Biologia Estrutural e Funcional, Belém, Pará, Brazil.; Instituto Evandro Chagas, Laboratório de Citogenética e Cultura de Tecidos-SAMAM, Ananindeua, Pará, Brazil., Vasconcelos CP; Instituto Evandro Chagas, Laboratório de Citogenética e Cultura de Tecidos-SAMAM, Ananindeua, Pará, Brazil., Mitre GP; Universidade Federal do Pará, Laboratório de Cultura Celular, Belém, Brazil., da Silva Kataoka MS; Universidade Federal do Pará, Laboratório de Cultura Celular, Belém, Brazil., Lima MO; Instituto Evandro Chagas, Laboratório de Toxicologia-SAMAM, Ananindeua, Pará, Brazil., de Oliveira EHC; Instituto Evandro Chagas, Laboratório de Citogenética e Cultura de Tecidos-SAMAM, Ananindeua, Pará, Brazil.; Universidade Federal do Pará, Instituto de Ciências Exatas e Naturais, Brazil., Lima RR; Universidade Federal do Pará, Laboratório de Biologia Estrutural e Funcional, Belém, Pará, Brazil.
Jazyk: angličtina
Zdroj: Oxidative medicine and cellular longevity [Oxid Med Cell Longev] 2019 Nov 22; Vol. 2019, pp. 8470857. Date of Electronic Publication: 2019 Nov 22 (Print Publication: 2019).
DOI: 10.1155/2019/8470857
Abstrakt: Human exposure to mercury (Hg) is primary associated with its organic form, methylmercury (MeHg), through the ingestion of contaminated seafood. However, Hg contamination is also positively correlated with the number of dental restorations, total surface of amalgam, and organic mercury concentration in the saliva. Among the cells existing in the oral cavity, human periodontal ligament fibroblast (hPLF) cells are important cells responsible for the production of matrix and extracellular collagen, besides sustentation, renewal, repair, and tissue regeneration. In this way, the present study is aimed at investigating the potential oxidative effects caused by MeHg on hPLF. Firstly, we analyzed the cytotoxic effects of MeHg (general metabolism status, cell viability, and mercury accumulation) followed by the parameters related to oxidative stress (total antioxidant capacity, GSH levels, and DNA damage). Our results demonstrated that MeHg toxicity increased in accordance with the rise of MeHg concentration in the exposure solutions (1-7  μ M) causing 100% of cell death at 7  μ M MeHg exposure. The general metabolism status was firstly affected by 2  μ M MeHg exposure (43.8 ± 1.7%), while a significant decrease of cell viability has arisen significantly only at 3  μ M MeHg exposure (68.7 ± 1.4%). The ratio among these two analyses (named fold change) demonstrated viable hPLF with compromised cellular machinery along with the range of MeHg exposure. Subsequently, two distinct MeHg concentrations (0.3 and 3  μ M) were chosen based on LC50 value (4.2  μ M). hPLF exposed to these two MeHg concentrations showed an intracellular Hg accumulation as a linear-type saturation curve indicating that metal accumulated diffusively in the cells, typical for metal organic forms such as methyl. The levels of total GSH decreased 50% at exposure to 3  μ M MeHg when compared to control. Finally, no alteration in the DNA integrity was observed at 0.3  μ M MeHg exposure, but 3  μ M MeHg caused significant damage. In conclusion, it was observed that MeHg exposure affected the general metabolism status of hPLF with no necessary decrease on the cell death. Additionally, although the oxidative imbalance in the hPLF was confirmed only at 3  μ M MeHg through the increase of total GSH level and DNA damage, the lower concentration of MeHg used (0.3  μ M) requires attention since the intracellular mercury accumulation may be toxic at chronic exposures.
Competing Interests: The authors declare no conflict of interest.
(Copyright © 2019 Lygia S. Nogueira et al.)
Databáze: MEDLINE
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