Staphylococcus aureus chronic intramammary infection modifies the expression of transforming growth factor beta (TGF-â) subfamily components during active involution

ANDREOTTI CS; PEREYRA EAL; BARAVALLE C; RENNA MS; ORTEGA HH; CALVINHO LF; DALLARD BE

RESEARCH IN VETERINARY SCIENCE

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2013 vol. 13 p. 1 - 10

0034-5288

The objectives of this study were to determine whether Staphylococcus aureus chronic intramammary infection (IMI) influences protein expression of TGF-b subfamily components and collagen I and to examine the histomorphometric changes that occur in mammary stroma and parenchyma during active mammary gland involution. Twenty-one Holstein non-pregnant cows in late lactation either uninfected or with chronic natural S. aureus IMI were included in this study. Cows were slaughtered at 7, 14 and 21 d after cessation of milking and samples for immunohistochemical and morphometric analysis were taken. Protein expression of TGF-b1, TGF-b2 and TGF-b3 was significantly higher in chronically infected quarters than in uninfected controls at the three involution stages studied. Immunostaining of TGF-bR1 and TGF-bR3 and collagen I was significantly higher in S. aureus-infected quarters than in uninfected controls at every involution time evaluated. The percentages of tissue area composed of parenchyma and intralobular stroma were significantly higher in S. aureus-infected than in uninfected quarters. Chronic S. aureus mastitis modifies protein expression of the three TGF-b isoforms and type 1 and 3 receptors, which was associated with changes directed to limit the scope of inflammation and injury to the host.