Cytokines in mammary lymph and milk during endotoxin-induced bovine mastitis
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Published on: September 4, 2012
K Persson Waller1, I G Colditz, S Lun
1Department of Ruminant and Porcine Diseases, National Veterinary Institute, SE-751 89, Uppsala, Sweden. Karin.Persson.Waller@sva.se
Insights
Interleukin-8 (IL-8) is key in recruiting neutrophils to the mammary gland after E. coli endotoxin exposure. Other cytokines like IL-1beta and TNF-alpha are not essential for this IL-8 response.
Area of Science:
- Veterinary Immunology
- Bovine Mastitis Pathogenesis
Background:
- Bovine mastitis is a significant economic challenge in dairy farming.
- Understanding the inflammatory response, particularly cytokine involvement, is crucial for developing effective treatments.
- Escherichia coli endotoxin is a common trigger for intramammary inflammation.
Purpose of the Study:
- To investigate the temporal dynamics of key cytokines in response to intramammary endotoxin challenge.
- To determine the role of specific cytokines in neutrophil recruitment to the mammary gland and lymph nodes.
- To elucidate the relationship between lymph and milk cytokine concentrations.
Main Methods:
- Intramammary infusion of Escherichia coli endotoxin in cows.
- Collection of milk and supramammary lymph (afferent and efferent) samples at 0, 2, and 4 hours post-infusion.
- Quantification of neutrophils and cytokines, including Interleukin-8 (IL-8), Tumor Necrosis Factor-alpha (TNF-alpha), IL-1beta, and Interferon-gamma.
Main Results:
- Neutrophils appeared in afferent lymph at 2 hours and in efferent lymph and milk by 4 hours post-infusion.
- High concentrations of IL-8 were detected in milk at 2 and 4 hours, with lower levels in lymph.
- IL-1beta increased in milk at 4 hours but was undetectable in lymph; TNF-alpha showed a trend of increase in afferent lymph and milk.
Conclusions:
- IL-8 plays a primary role in mediating neutrophil recruitment into the mammary gland following endotoxin exposure.
- IL-1beta and TNF-alpha do not appear to be necessary for the initial IL-8 production and release in this model.
- Cytokine profiles in milk reflect, to some extent, the inflammatory processes occurring within the mammary gland.
Abstract:
Cytokine kinetics were examined in milk and in afferent and efferent lymph of the supramammary lymph node after intramammary infusion of endotoxin from Escherichia coli. Cows were sampled 0, 2 and 4h after infusion (p.i.). Neutrophils appeared in afferent lymph 2h p.i., and in efferent lymph and milk 4h p.i. The milk contained high concentrations of interleukin-8 (IL-8) at 2 and 4h p.i. IL-8 was also found in lymph, but at lower concentrations. The tumor necrosis factor-alpha (TNF-alpha) concentration tended to increase in afferent lymph at 2h p.i., and increased in milk at 4h p.i. The level of IL-1beta increased at 4h p.i. in milk, but was not detected in lymph. Interferon-gamma was not detected in any sample, at any time. The results indicate a primary role for IL-8 in the recruitment of neutrophils into the gland, and suggest that IL-1beta and TNF-alpha are not necessary for IL-8 production and release in response to endotoxin.
