Study of the evolution of acute phase reactants and of thromboxane and prostacyclin during calcium pyrophosphate-induced pleurisy in the rat.

By using a clearly defined model of acute inflammation in rats, CaPP-induced pleurisy, we compared the evolution of four APR levels (Hp, HpX, alpha 2M, SAP) at a local and peripheral site. At the same time we studied thromboxane and prostacyclin concentrations in pleural exudate. The levels of APR have shown a progressive increase up to 24 h. For alpha 2M, Hp, HpX the increase in serum concentration was more rapid than in exudate, whereas the evolution of SAP level was parallel in the intra and extra-vascular compartments. On the other hand the levels of albumin and transferrin which are not APR remained constant in serum and also in exudate from 6 h to 24 h. Thromboxane and prostacyclin levels reached a peak during the first two hours of the inflammatory reaction followed by a rapid decreased. These prostanoids may be considered as early and transient mediators of acute inflammation, whereas the acute phase proteins studied have a more prolonged role in the inflammatory reaction.