RESUMEN
Objective To investigate the proof of fetal cells passing through the placental barrier into the maternal peripheral blood to provide laboratory data for the non invasive prenatal gene diagnosis of genetic diseases. Methods A total of 22 samples of placental tissues delivered(male fetus: 12, female fetus: 11) were divided into two groups for parallel section. HE staining was used to find the distribution of fetal cells in chorionic villi. In situ hybridization (ISH) technique with SRY DNA probes was used to identify the existence of fetal cells in placental villi, particularly in intervillous space. Results Light microscope examination revealed that there were fetal cells that passed through the capillary endothelium of villi and trophoblast basement membrane in the placental tissue sections of the 22 samples. ISH with SRY DNA probe also revealed that there were positive signals in the capillary of villi, at the edge of trophoblast basement membrane and in intervillous space in the placental tissue sections of the 12 placentas, but no signals were found in 10 female placentas. Conclusion This study demonstrates that the distribution of the fetal cells in the chorionic villi and intervillous space could be identified. The detection of fetal DNA in maternal circulation is one of the candidate approaches for non invasive prenatal gene diagnosis.