A study of the development of endotoxin-induced inflammation in the bovine teat.

Endotoxin-induced local inflammation was studied by frequent samplings in a bovine teat cistern model, which provides a unique possibility for in vivo studies of reactions in the teat without interference from the mammary gland. A rapid inflammatory response of rather short duration was elicited after endotoxin administration. An initial increase in the concentrations of bovine serum albumin and N-acetyl-beta-D-glucosaminidase, indicating a disturbance in the epithelial integrity, was observed between 1 and 1.5 h post infusion (p.i.). Approximately 0.5 h later, the first influx of leukocytes, mainly neutrophils, appeared. The neutrophils tended to enter the teat cistern in several peaks occurring between 2.5 and 5 h p.i. The sampling procedure decreased the accumulation of cells by approximately 40%, which was probably due to the removal of inflammatory mediators at an early stage. The parallel use of 2 teats instead of 1 had no major influence on the inflammatory process. This teat cistern model and the experimental procedure used should be suitable for further studies of the development of local inflammation.