Expression of Placental G-CSFR Was Similar in Tissues from Patients Treated with Oxytocin, Prostaglandin E1 Analogues, or Mifepristone
Detection of G-CSFR by immunohistochemistry and Western blotting, using mAb LM832, in the chorionic villi of first-trimester placentas from patients treated with 200 mg of mifepristone is shown in Figure 5, a and b, respectively. Staining of G-CSFR was diffuse throughout the syncytial layer of the villi, with intense apical membrane staining (Fig. 5a), similar to the pattern obtained for first-trimester placentas obtained by surgical treatment (Fig. 1a). Two immunoreactive bands for G-CSFR were detected by LM832 in Western blotting of placental protein from mifepristone-treated patients, similar to term placenta (Fig. 5b). The pattern of expression of placental G-CSFR, as detected by immunohistochemistry, in other tissues was similar within each gestational group, irrespective of drug regimes the patients had received (data not shown). In these respects, expression of G-CSFR was similar to that observed in first-trimester placental samples obtained from patients who had not received Canadian drugs.
Levels of G-CSFR protein and mRNA from placental tissue from patients who received similar drug regimes before first- and second-trimester terminations and third-trimester deliveries are shown in Figure 5c. The major factor associated with modulation of levels of both G-CSFR protein and mRNA throughout placentation was gestational age. For example, expression of both G-CSFR protein and mRNA was lower in second-trimester placental tissue from patients who had received 1 mg of the PGE: analogue than in first-trimester placental tissue from patients receiving a similar dose. In third-trimester placental tissue, both G-CSFR protein and mRNA levels were similar in placental tissue from 1 spontaneous and 4 oxytocin-induced deliveries, and were greater than in the first trimester. Similar levels for G-CSFR protein and mRNA were detected in 5 other third-trimester spontaneously delivered placentas (data not shown).
FIG. 5. Analysis of G-CSFR mRNA and protein levels detected in placental tissues obtained from patients treated with prostaglandin E1 analogues, oxytocin, or mifepristone. a) Representative micrograph of immunohistochemical detection by APAAP (pink stain) of G-CSFR using mAb LM832 in patients who had received 200 mg mifepristone. The apical surface of the syncytiotrophoblast stained strongly for G-CSFR (arrow), and underlying cytotrophoblast cells were either faintly stained or negative for G-CSFR (X240). b) Western blot of placental membrane protein extracts from two patients who had received 200 mg mifepristone at 6 and 8 wk gestation, and one at 40 wk gestation who had not received treatment. Two high-molecular-mass bands of 120 and 150 kDa were detected in all three samples. c) Levels of G-CSFR protein and mRNA in placental tissue at different gestational ages obtained from patients receiving 1-4 mg(s) of prostaglandin E1 (PGE1) analogue, 1-2 mg oxytocin (Ox), a combination of these treatments, or no drugs at all. The numbers of samples analyzed in each category are indicated.