EFFECT OF BACTERIAL-CELL WALL AND LIPOPOLYSACCHARIDE ON ARACHIDONIC-ACID METABOLISM BY CARUNCULAR AND ALLANTOCHORIONIC TISSUES FROM COWS THAT CALVED NORMALLY AND THOSE THAT RETAINED FETAL MEMBRANES

Immunoactive eicosanoids may have a role in both placental separation and uterine involution in cattle. In the present study, we examined th e effects of bacterial cell wall preparation and endotoxins on in vitr o prostaglandin synthesis and arachidonic acid (AA) metabolism by caru ncular and allantochorionic tissues. placentomes were obtained about 6 h post partum from cows that delivered normally (n = 10) or those wit h retained fetal membranes (n = 4), the tissue explants were incubated for 6 h in the presence of labeled or nonlabeled AA. Prostaglandin F- 2 alpha (PGF(2 alpha)) and E(2) (PGE(2)) were measured by radioimmunoa ssay, and labeled AA metabolites were separated by reverse phase-high pressure-liquid chromatography. There was no effect of bacterial cell wall preparations or endotoxins on in vitro caruncular PGF(2 alpha) se cretion. However, bacterial products increased caruncular PGE(2) secre tion in both cows that delivered normally and those with retained feta l membranes. For normal delivery cows caruncular tissue, bacterial pro duct also increased leukotriene B-4 (LTB(4)) and decreased both thromb oxane B-2 (TXB(2)) and hydroxy-eicosatetranoic acids (HETE) in vitro s ecretion. For the allantochorion, bacterial products secretion only in cows that delivered increased in vitro PGF(2 alpha) normally and incr eased PGE(2) secretion essentially in cows with retained fetal membran es. In general, 6 keto PGF(1 alpha) was the main metabolite secreted b y both allantochorionic and carucular tissues. However, in cows with r etained fetal membranes, PGE(2) became the most important metabolite s ecreted by allantochorion, especially in the presence of endotoxin. In conclusion, these results suggest that bacteria found in the early po stpartum uterus or their endotoxin affect primarily caruncular and all antochorionic PGE(2) synthesis.