RELEASE OF PROINFLAMMATORY CYTOKINES RELATED TO LUTEOLYSIS AND THE PERIPARTURIENT ACUTE-PHASE RESPONSE IN PROSTAGLANDIN-INDUCED PARTURITIONIN COWS

An acute phase response was previously found in cows at parturition, w hich might be associated with uterine cytokine release. Five late preg nant cows were implanted with vascular catheters in both the maternal aorta and uterine vein. Blood samples were taken to study temporal rel ationships between changing plasma levels of proinflammatory cytokines and the periparturient acute phase response following prostaglandin ( PG)-induced luteolysis at Day 275 of gestation. The plasma levels of t hree proinflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha ), interleukin-1 (IL-1) and interleukin-6 (IL-6), as well as progester one (P4), PGFM and serum amyloid A (SAA) were measured every 4 h betwe en PG induction and expulsion of the calf. In the arterial plasma, pro gesterone levels dropped to baseline levels within 10 h following PG t reatment, indicative of complete luteolysis. Contrary to expectations, the uterine vein samples showed lower proinflammatory cytokine levels compared with the maternal aorta values. A classical acute phase resp onse, as assessed by SAA, was observed during the expulsive stage, but not during luteolysis. (C) 1998 by Elsevier Science Inc.