INVESTIGADORES
ORTEGA Hugo Hector
artículos
Título:
Effect of a biological response modifier on cellular death mechanisms at drying off
Autor/es:
E DALLARD, BIBIANA; CELINA BARAVALLE,; ORTEGA, HH; VALERIA RUFFINO,; SOLEDAD HEFFEL,; F CALVINHO, LUIS
Revista:
Journal of Dairy Research
Editorial:
CAMBRIDGE UNIV PRESS
Referencias:
Año: 2008 vol. 75 p. 167 - 175
ISSN:
0022-0299
Resumen:
Agents that increase natural protective mechanisms have been proposed for prevention and
treatment of intramammary infections. The objective of this study was to describe the effects of
a single intramammary infusion of a lipopolysaccharide (LPS)-based biological response modifier
(BRM) on cellular death mechanism in uninfected and Staphylococcus aureus-infected bovine
mammary glands during involution. Three groups of 12 cows, each one including 6 Staph.
aureus-infected and 6 uninfected, were infused in two mammary quarters with BRM or placebo
and slaughtered at 7, 14 and 21 d of involution. In infected quarters, BRM treatment produced a
significant increase in percent of stained epithelial cells for the apoptosis-promoting protein Bax
at every observation period. In addition, BRM produced a significant increase of immunostained
stromal cells for Bax compared with placebo-treated quarters. BRM treatment produced an
increase in percentages of epithelial cells staining with active caspase-3 at 7 d and 14 d of
involution compared with placebo-treated quarters and a significant decrease in percentages of
terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL)-positive epithelial cells
at 7 d and 21 d of involution. In addition, BRM treatment caused an increase in percentage of
stromal cells immunostaining for active caspase-3 and TUNEL. An increase of active caspase-3
and TUNEL epithelial and stromal cell immunostaining was observed in Staph. aureus-infected
compared with uninfected quarters. Cellular proliferation, determined by Ki-67 immunostaining,
was increased in epithelial and stromal cells from Staph. aureus-infected compared with
uninfected quarters at every observation period. These results provide new insights into the
mechanism of mammary cell death in uninfected and Staph. aureus-infected bovine mammary
gland during involution and illustrate the effects of LPS-based BRM on apoptosis and cell
proliferation during mammary involution.