Conjugated linoleic acid isomers strongly improve the redox status of bovine mammary epithelial cells (BME-UV1)
Author(s)
Date Issued
2015
Type
article
Volume
98
Issue
98
Start Page
7071
End Page
7082
ISSN
15253198
220302
Journal
Abstract
Some studies have shown the protective effects of
conjugated linoleic acid (CLA) isomers against oxidative stress and lipid peroxidation in animal models, but
no information is available about CLA and changes in
oxidative status of the bovine mammary gland. The
objectives of the study were to assess in vitro the effect of CLA on the cellular antioxidant response of
bovine mammary cells, to examine whether CLA isomers could play a role in cell protection against the
oxidative stress, and to study the molecular mechanism
involved. For the study, BME-UV1 cells, a bovine
mammary epithelial cell line, were used as the experimental model. The BME-UV1 cells were treated with
complete medium containing 50 µM cis-9,trans-11 CLA
(c9,t11 CLA), trans-10,cis-12 CLA (t10,c12 CLA),
and CLA mixture (1:1, cis-9,trans-11: trans-10,cis-12
CLA). To monitor cellular uptake of CLA isomers, cells
and culture medium were collected at 0, 3, and 48 h
from CLA addition for lipid extraction and fatty acid
analyses. To assess the cellular antioxidant response,
glutathione (GSH/GSSH), NADPH, and γ-glutamylcysteine ligase activity was measured after 48 h from
addition of CLA. Cytoplasmic superoxide dismutase,
glutathione peroxidase, glutathione S-transferase, and
glutathione reductase activities and mRNA were also
determined. Intracellular reactive oxygen species and
thiobarbituric acid reactive substance production were
assessed in cells supplemented with CLA isomers. Cell
viability after 3 h to H2O2 exposure was assessed to
evaluate and to compare the potential protection of
different CLA isomers against H2O2-induced oxidative stress. Mammary cells readily picked up all CLA
isomers, their accumulation was time dependent, and
main metabolites at 48 h are two 18:3 isomers. The CLA treatment induced an intracellular GSH increase,
matched by high concentration of NADPH, and an increase of γ-glutamyl-cysteine ligase activity mainly in
cells treated with the t10,c12 CLA isomer. The CLA
isomer treatment of bovine mammary cells increased
superoxide dismutase, glutathione peroxidase, and glutathione S-transferase activity and decreased glutathione reductase activity, but no changes in gene expression of these antioxidant enzymes were observed. Cells
supplemented with CLA isomers showed a reduction in
intracellular reactive oxygen species and thiobarbituric
acid reactive substance levels. All CLA isomers were
able to enhance cell resistance against H2O2-induced
oxidative stress. These suggest an antioxidant role of
CLA, in particular of t10,c12 CLA, by developing a
significantly high redox status in cells.
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JDS_9787 proof corrected.pdf
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Conference(s)
JOURNAL OF DAIRY SCIENCE