CSF1 and MIF Expression in Term Decidua
The distributions of the CSF1 and MIF proteins in term decidua were analyzed by immunohistochemistry. Strong immunostaining for CSF1 (Fig. 1, A and B) and MIF (Fig. 1, C and D) were observed in the decidua. Observations at higher magnification revealed that both proteins were primarily distributed in the cytoplasm. Intense immunostaining was also detected in the syncytiotrophoblast (CSF1) and cytotrophoblast (MIF) of the chorionic villi. In addition, MIF immunoreactivity was consistently found in extravillous trophoblasts (data not shown). Staining for both cytokines was eliminated by substituting non-immune serum for the primary antibodies (data not shown).
Regulation of CSF1 and MIF Expression in Decidual Cells
As circulating levels of both E2 and progesterone are high during the third trimester, E2 was used as the control for evaluating the effects of the synthetic progestin MPA. Figure 2 indicates that in cultures maintained with E2 alone, 1 ng/ml of TNF or IL1B increased CSF1 output from 0.1 6 0.02 ng/ml/ mg protein in the control cultures to 0.54 6 0.18 (mean 6 SEM; P < 0.05) and 0.7 6 0.14 (P < 0.05) ng/ml/mg protein, respectively.
FIG. 1. Immunohistochemical analysis of CSF1 (A, B) and MIF (C, D) expression in term decidua. Immunohistochemistry was performed by an indirect peroxidase technique (detailed in the Materials and Methods section). Original magnification A, C X 100;B, D X 400.
FIG. 2. Effects of E2 MPA, TNF, and IL1B on CSF1 production by term decidual cell monolayers. Confluent, leukocyte-free decidual cells were incubated for 7 days with 10~8 M E2 or with E2 + 10~7 M MPA, and then switched to DM with the corresponding steroid(s) with or without 1 ng/ml of TNF or IL1B for 24 h. The CSF1 levels in conditioned DM were measured by ELISA and normalized to the level of cell protein (n = 6, mean ± SEM). *, versus E2 (P < 0.05);**, versus E2 + MPA (P < 0.05).