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BioMed Research International
Volume 2014, Article ID 597357, 9 pages
http://dx.doi.org/10.1155/2014/597357
Research Article

Effect of Hypoxia on the Calcium and Magnesium Content, Lipid Peroxidation Level, and Ca2+-ATPase Activity of Syncytiotrophoblast Plasma Membranes from Placental Explants

1Laboratorio de Bioenergética Celular, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas (IVIC), IVIC-CBB, Apartado Postal 21827, Caracas 1020A, Venezuela
2Laboratorio de Química Analítica, Centro de Química, Instituto Venezolano de Investigaciones Científicas (IVIC), Apartado Postal 21827, Caracas 1020A, Venezuela

Received 27 March 2014; Revised 22 July 2014; Accepted 23 July 2014; Published 7 August 2014

Academic Editor: Luis Sobrevia

Copyright © 2014 Delia I. Chiarello et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

In the current study the possible relationship between the Ca2+/Mg2+ ratio of human syncytiotrophoblast plasma membranes and their lipid peroxidation and Ca2+-ATPase activity was determined. Syncytiotrophoblast plasma membranes of placental explants cultured under hypoxia increased their lipid peroxidation and Ca2+ content, diminished their Ca2+-ATPase activity, and kept their Mg2+ content unchanged. Membranes preincubated with different concentrations of Ca2+ increased their Ca2+ content without changes in their Mg2+ content. There is a direct relationship between Ca2+ content and lipid peroxidation of the membranes, as well as an inverse relationship between their Ca2+ content and Ca2+-ATPase activity. On the contrary, preincubation of membranes with different concentrations of Mg2+ showed a higher Mg2+ content without changing their lipid peroxidation and Ca2+-ATPase activity. Explants cultured under hypoxia in the presence of 4 mM MgSO4 showed similar values of lipid peroxidation and Ca2+-ATPase activity of their membranes compared to those of explants cultured under normoxia. Increased Ca2+ content of the membranes by interacting with negatively charged phospholipids could result in destabilizing effects of the membrane structure, exposing hydrocarbon chains of fatty acids to the action of free radicals. Mg2+ might exert a stabilizing effect of the membranes, avoiding their exposure to free radicals.