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Mastitis increases growth factor messenger ribonucleic acid in bovine mammary glands
1Department of Dairy Science, University of Wisconsin, Madison 53706, USA.
Multiparous Holstein cows were infected in two quarters by intramammary infusion with Streptococcus agalactiae and slaughtered approximately 36 h later. Mammary tissue was removed from the infected quarters, uninfected contralateral quarters, and from pair-slaughtered uninfected controls; the tissue was frozen in liquid nitrogen. The RNA was extracted, and Northern blot analysis was performed for a variety of growth factors, stress-induced genes, milk protein genes, and control genes. Infection increased levels of mRNA coding for heat shock proteins 89 alpha, 89 beta, 70, 60, and 27. Simultaneously, concentrations of alpha-lactalbumin and casein mRNA decreased; alpha-lactalbumin mRNA showed a greater decline. The mRNA for several growth factors, including acidic fibroblast growth factor, basic fibroblast growth factor, epidermal growth factor, transforming growth factor-alpha, IGF-I, and IGF-II, were also increased as was the apoptosis marker, testosterone-repressed prostate mucin-2. Concentrations of mRNA for controls, beta-actin, and glyceraldehyde-3-phosphate dehydrogenase were unaffected. These results indicate that mastitis induces changes in the levels of mRNA encoding for a variety of peptide growth factors. Such changes in growth factors could be important in a variety of processes that occur during infection, such as protection against injury or tissue repair and recovery processes.
Multiparous Holstein cows were infected in two quarters by intramammary infusion with Streptococcus agalactiae and slaughtered approximately 36 h later. Mammary tissue was removed from the infected quarters, uninfected contralateral quarters, and from pair-slaughtered uninfected controls; the tissue was frozen in liquid nitrogen. The RNA was extracted, and Northern blot analysis was performed for a variety of growth factors, stress-induced genes, milk protein genes, and control genes. Infection increased levels of mRNA coding for heat shock proteins 89 alpha, 89 beta, 70, 60, and 27. Simultaneously, concentrations of alpha-lactalbumin and casein mRNA decreased; alpha-lactalbumin mRNA showed a greater decline. The mRNA for several growth factors, including acidic fibroblast growth factor, basic fibroblast growth factor, epidermal growth factor, transforming growth factor-alpha, IGF-I, and IGF-II, were also increased as was the apoptosis marker, testosterone-repressed prostate mucin-2. Concentrations of mRNA for controls, beta-actin, and glyceraldehyde-3-phosphate dehydrogenase were unaffected. These results indicate that mastitis induces changes in the levels of mRNA encoding for a variety of peptide growth factors. Such changes in growth factors could be important in a variety of processes that occur during infection, such as protection against injury or tissue repair and recovery processes.