Submitted to: American Journal of Veterinary Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/23/2008
Publication Date: 3/20/2009
Citation: Bannerman, D.D., Rinaldi, M., Vinyard, B.T., Laihia, J., Lein0, L. 2009. Effects of intramammary infusion of cis-urocanic acid on mastitis-associated inflammation and tissue injury in dairy cows. Bannerman, DD, Rinaldi, M., Vinyard, BT, Laihia J., Leino L. American Journal of Veterinary Research. 70(3):373-382.
Interpretive Summary: Mastitis remains a prevalent disease in dairy cows and is one of the most costly diseases in animal agriculture. A deleterious outcome of this disease is inflammation-induced injury to mammary tissue, which can delay recovery and lead to prolonged reduction in milk output. The objective of the current study was to evaluate the effect of cis-urocanic acid on inflammation and injury elicited in response to mastitis caused by Escherichia coli, a prevalent cause of acute clinical cases of mastitis. The major finding of this study was that cis-urocanic acid can protect against mastitis-associated injury without impairing the ability of the cow to mount an inflammatory response necessary to eradicate the infecting pathogen. The results of this study are important to the dairy industry and veterinarians as it establishes a beneficial therapeutic application for cis-urocanic acid in protecting cows with mastitis against injury that is commonly associated with this disease.
Technical Abstract: Objective – To evaluate the effect of cis-urocanic acid (cis-UCA) on inflammation and injury elicited in response to Escherichia coli-induced mastitis. Animals – Twelve lactating Holstein dairy cows; thirty-six mammary glands Procedures – A 3x3 Latin square cross-over design was used to evaluate the effects of a control solution or two concentrations of cis-UCA on the clinical course of Escherichia coli intramammary infection. Immediately prior to and at various time points after experimental infection and treatment, milk samples were aseptically collected. The bacterial colony forming units (CFU), somatic cell counts (SCC), N-acetyl-beta-D-glucosaminidase (NAGase) activity, and concentrations of bovine serum albumin (BSA), tumor necrosis factor-' (TNF-'), lactate dehydrogenase (LDH), and cis-UCA, were quantified in each milk sample. Results – Milk samples from mammary glands infected with E. coli and treated with cis-UCA demonstrated decreased NAGase activities and LDH concentrations compared with samples collected from infected quarters infused with the control saline solution. Cis-UCA had no effect on other inflammatory indices, including milk SCC and milk concentrations of BSA and TNF-'. Further, cis-UCA had no adverse effect on bacterial clearance as demonstrated by the equivalent CFU of E .coli in infected glands receiving the control solution or cis-UCA. Conclusions and Clinical Relevance – The finding that two indices of cell injury, NAGase activity and LDH concentration, were both lower in infected glands treated with cis-UCA than in those infused with a control solution, suggests that cis-UCA reduces mastitis-associated tissue damage. Further, these data demonstrate that therapeutic levels of cis-UCA in milk can be achieved by intramammary infusion.