Effects of folic acid and homocysteine on spinal cord morphology of the chicken embryo

Abstract

Maternal ingestion of folic acid (FA) reduces neural tube defects, which are associated with high homocysteine levels. Present study evaluated the effects of FA and homocysteine on cell proliferation and cell adhesion, as well as on apoptosis, throughout the development of the spinal cord and mesenchyme of chicken embryos. Normal closure of the neural tube and a regular distribution of the mesenchymal cells were observed in control and FA-treated embryos. All homocysteine-treated embryos and also 6 of 10 embryos treated with FA+homocysteine showed failure of closure of the neural tube. Homocysteine decreased the thickness of the mantle and marginal layers of the spinal cord, and FA did not prevent this effect. FA treatment reversed the decrease of proliferating cells in the spinal cord induced by homocysteine. FA-treated embryos showed the highest numerical density of apoptotic cells. Homocysteine treatment reduced NCAM expression in both spinal cord and mesenchymal tissue, and FA prevents this effect. These results are important because they demonstrate in situ that the imbalance between FA and homocysteine levels can lead to disruptions in spinal cord development, changing proliferation, apoptosis, and cell adhesion and consequently changing the arrangement of the spinal cord layers.

Occurrence of Cleft-Palate and Alteration of <i>Tgf-</i>β_<i>3</i> Expression and the Mechanisms Leading to Palatal Fusion in Mice following Dietary Folic-Acid Deficiency

“…The fact that cell proliferation was even more reduced in the MEE of embryos of dams fed the FAD diet for 2 weeks suggests that in the palate FA has a more proliferative rather than differentiating effect. This was also reinforced by the significant reduction in cell proliferation observed in the mesenchyme of the FAD mouse palates and is consistent with the proliferative effect exerted by FA in other embryonic systems [Kobus et al, 2009;McNeil et al, 2009].…”

“…FA is a potent cell proliferation agent [Kobus et al, 2009;Lindzon et al, 2009;Zhang et al, 2009] and FA deficiency has been shown to alter cell proliferation [Duthie et al, 2008]. To investigate whether cell proliferation was impaired in the developing palate of embryos of dams fed the FAD diet for 2 weeks, we compared the presence of proliferating cells in both the MEE and mesenchyme from the control embryos and the embryos of dams fed the FAD diet for 2 weeks at the anterior, middle and posterior parts of the palate.…”

“…Only a delay in palate development has been observed in the progeny of female mice which had been on an FA-deficient (FAD) diet for 4 weeks [Burgoon et al, 2002], and the mechanisms by which FA acts during palate development remain unknown. In other tissues, FA deficiency was proven to alter the expression and activity of proteins involved in cell proliferation, cell-cell adhesion, cell migration and cell death [Crott et al, 2008;Duthie et al, 2008;Hwang et al, 2008a, b;Kobus et al, 2009], which are all crucial mechanisms in palatal fusion [Ferguson, 1988]. In this work, we aimed to determine whether or not dietary FA deficiency in mouse embryos impairs palatal-shelf proliferation, MEE cell adhesion, MES cell death and disintegration, and produces CP.…”

Extending the knowledge in histochemistry and cell biology

“…Maternal ingestion of folic acid (FA) reduces neural tube defects. Kobus et al (2009) studied the eVects of FA and homocysteine on cell proliferation, adhesion, as well as apoptosis during spinal development in chicken embryos. Homocysteinetreated embryos and also six of ten embryos treated with FA and homocysteine showed failure of closure of the neural tube.…”

Homocysteine causes disruptions in spinal cord morphology and changes the expression of Pax 1/9 and Sox 9 gene products in the axial mesenchyme

“…Other developmental studies demonstrated that Hcy affects the neural tissues, leading to NTD (Rosenquist et al, ; Maestro de las Casas et al, ; Afman et al, ). Our previous study (Kobus et al, ) demonstrated that Hcy induces spinal NTD in chickens, altering cell proliferation and cell adhesion in both neural and non‐neural embryonic tissues. Although the current literature reports that high Hcy levels are related to NTD occurrence, and spinal NTD are related to disruptions in vertebral elements, few experimental studies have examined the effects of an FA/Hcy imbalance on the axial mesenchyme development.…”