Concentration of Macrophage Colony-Stimulating Factor (M-CSF) in Bovine Peripheral Blood during Pregnancy

Abstract

Macrophage colony-stimulating factor (M-CSF) is a hemopoietic cytokine with a primary role in placental physiology. Gene expression of M-CSF in the bovine endometrium shows a temporal upward trend during early and mid pregnancy. This study determined the plasma M-CSF levels during pregnancy using ELISA. In experiment 1, to investigate the relationship between the concentration of M-CSF in peripheral blood and pregnancy, the plasma M-CSF levels were determined in 125 pregnant and 21 non-pregnant Japanese Black cows. The pregnant animals were divided into nine groups based on the month of pregnancy. An ELISA for bovine M-CSF established previously was used according to the authors' instructions. In experiment 2, the plasma M-CSF level was determined to investigate the temporal changes in its concentration in the peripheral blood during pregnancy. In experiment 1, the plasma M-CSF level varied from month to month during pregnancy; the mean level in the first-month of pregnancy was significantly higher than those in the third and last months of pregnancy and non-pregnancy (P<0.05). In experiment 2, the plasma M-CSF level varied with the day of pregnancy (P<0.05). The mean level of plasma M-CSF decreased gradually until 6 weeks of pregnancy; it appeared to increase during weeks 7-9, then varied with several small peaks until 27 weeks of pregnancy and finally decreased gradually until parturition. These results suggest that the plasma M-CSF level may be related to changes in the uterus and placenta as pregnancy progresses.