Objectives: In the present study, we evaluated functional activity of monocytes in experimental preeclampsia induced by low-dose endotoxin infusion.
Study design: Pregnant (n = 12) and cyclic rats (n = 12) were equipped with a permanent jugular vein cannula and infused with either low-dose endotoxin or saline. One day before the infusion, and 4, 24, 72, and 168 hours after the infusion, blood samples (400 microL) were taken and white blood cell (WBC) and differential cell counts were measured. Samples were (re)stimulated with endotoxin, and the percentage of tumor necrosis factor-alpha (TNFalpha) producing monocytes was measured.
Results: During experimental preeclampsia, monocyte TNFalpha production is persistently decreased, while total WBC and granulocyte counts are persistently increased compared with normal pregnant rats. No persistent effect of endotoxin was found in cyclic rats.
Conclusion: Because decreased endotoxin-induced TNFalpha production is a feature of activated monocytes, the present results indicate that monocytes are persistently activated in experimental preeclampsia. Increased WBC counts and granulocyte numbers in these rats also point to an activated inflammatory response.