Effect of a Biological Response Modifier on Expression of Growth Factors and Cellular Proliferation at Drying Off

• Published in: Journal of dairy science Vol. 90; no. 5; pp. 2229 - 2240
• Main Authors: Dallard, B.E., Ruffino, V., Heffel, S., Calvinho, L.F.
• Format: Journal Article
• Language: English
• Published: Savoy, IL Elsevier Inc 01.05.2007; American Dairy Science Association; Am Dairy Sci Assoc
• Subjects: animal pathogenic bacteria; Animal productions; Animals; Antibodies, Bacterial - metabolism; Biological and medical sciences; biological response modifier; biological response modifiers; bovine mastitis; Cattle; cell proliferation; Cell Proliferation - drug effects; cellular proliferation; dairy cows; dry period; epithelial cells; Female; Food engineering; Food industries; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Regulation - drug effects; General aspects; Immunologic Factors - administration & dosage; Immunologic Factors - pharmacology; insulin-like growth factor I; Insulin-Like Growth Factor I - genetics; lipopolysaccharides; Lipopolysaccharides - administration & dosage; Lipopolysaccharides - pharmacology; mammary gland involution; Mammary Glands, Animal - cytology; Mammary Glands, Animal - drug effects; Mammary Glands, Animal - microbiology; mammary involution; Mastitis, Bovine - drug therapy; Mastitis, Bovine - microbiology; Mastitis, Bovine - prevention & control; protein synthesis; Staphylococcus aureus; Staphylococcus aureus - physiology; Terrestrial animal productions; Time Factors; udder quarters; udders; Vascular Endothelial Growth Factor A - genetics; vascular endothelial growth factors; Vertebrates; biological response modifier; mammary gland involution; Staphylococcus aureus; cellular proliferation; Biological response modifier; Involution; Dairy industry; Bacteria; Micrococcales; Micrococcaceae; Biological effect; Mammary gland; Growth factor; Drying
• ISSN: 0022-0302; 1525-3198
• DOI: 10.3168/jds.2006-653

Agents that increase natural protective mechanisms have been proposed for the prevention and treatment of intramammary infections. Staphylococcus aureus is a major pathogen causing primarily subclinical chronic mastitis that responds poorly to antibiotic therapy. The objectives of this study were to describe the effects of a single intramammary infusion of a lipopolysaccharide-based biological response modifier (BRM) on mammary epithelial cellular proliferation and expression of insulin-like growth factor-I (IGF-I) and vascular endothelial growth factor (VEGF) in uninfected and Staph. aureus-infected bovine mammary glands during involution. Three groups of 12 cows, 6 Staph. aureus-infected and 6 uninfected, were infused with BRM or placebo in 2 mammary quarters and killed at 7, 14, and 21 d of involution. The proportion of infected quarters, mammary cell proliferation, and IGF-I and VEGF expression were evaluated. Biological response modifier treatment decreased the proportion of Staph. aureus-infected mammary quarters at 7 d of involution, but a similar number of isolations were observed at 14 and 21 d of involution in either treated or control quarters. The percentage of proliferating mammary epithelial cells was higher in infected than uninfected quarters at every observation period, irrespective of the treatment administered, whereas uninfected BRM-treated quarters showed increased cell proliferation at 7 d of involution. Insulin-like growth factor-I expression in uninfected quarters was not affected by treatment and showed a decrease at 21 d of involution. Expression of IGF-I was greater in infected than uninfected quarters at every observation period, irrespective of the treatment received. Expression of VEGF was greater in BRM-treated uninfected quarters at 7 d of involution compared with controls. In infected quarters, VEGF expression was lowest in BRM-treated quarters at 7 d of involution and increased throughout the observation period. Conversely, untreated infected quarters showed the highest VEGF expression at 7 d and decreased at 21 d of involution. Mammary cell proliferation and expression of IGF-I and VEGF were increased in Staph. aureus-infected quarters. Increased mammary cell proliferation and VEGF expression were observed in BRM-treated quarters during the first week of involution.