title: MeHg Developing Exposure Causes DNA Double-Strand Breaks and Elicits Cell Cycle Arrest in Spinal Cord Cells.
abstract: The neurotoxicity caused by methylmercury (MeHg) is well documented; however, the developmental neurotoxicity in spinal cord is still not fully understood. Here we investigated whether MeHg affects the spinal cord layers development. Chicken embryos at E3 were treated in ovo with 0.1 μg MeHg/50 μL saline solution and analyzed at E10. Thus, we performed immunostaining using anti-γ-H2A.X to recognize DNA double-strand breaks and antiphosphohistone H3, anti-p21, and anti-cyclin E to identify cells in proliferation and cell cycle proteins. Also, to identify neuronal cells, we used anti-NeuN and anti-βIII-tubulin antibodies. After the MeHg treatment, we observed the increase on γ-H2A.X in response to DNA damage. MeHg caused a decrease in the proliferating cells and in the thickness of spinal cord layers. Moreover, we verified that MeHg induced an increase in the number of p21-positive cells but did not change the cyclin E-positive cells. A significantly high number of TUNEL-positive cells indicating DNA fragmentation were observed in MeHg-treated embryos. Regarding the neuronal differentiation, MeHg induced a decrease in NeuN expression and did not change the expression of βIII-tubulin. These results showed that in ovo MeHg exposure alters spinal cord development by disturbing the cell proliferation and death, also interfering in early neuronal differentiation.
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, UFSC, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil; Instituto de Ciências Naturais Humanas e Sociais, UFMT, Avenida Alexandre Ferronato 1200, Setor Industrial, 78557287 Sinop, MT, Brazil.
authors.forename: Fabiana F
authors.initials: FF
authors.lastname: Ferreira
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, UFSC, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil; Centro Universitário Católica de Santa Catarina, Rua Visconde de Taunay 427, Centro, 89203-005 Joinville, SC, Brazil.
authors.forename: Dib
authors.initials: D
authors.lastname: Ammar
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, UFSC, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Gilian F
authors.initials: GF
authors.lastname: Bourckhardt
authors.affiliation: Departamento de Fisioterapia, Centro de Ciências da Saúde e do Esporte, UDESC, Rua Pascoal Simone 358, Coqueiros, 88080-350 Florianópolis, SC, Brazil.
authors.forename: Karoline
authors.initials: K
authors.lastname: Kobus-Bianchini
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, UFSC, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Yara M R
authors.initials: YM
authors.lastname: Müller
authors.affiliation: Departamento de Biologia Celular, Embriologia e Genética, Centro de Ciências Biológicas, UFSC, Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Evelise M
authors.initials: EM
authors.lastname: Nazari