[Cytofluorometric nuclear DNA analysis and immunohistochemical study on the proliferative activity of the trophoblasts in human early gestation].

Changes in proliferative activity in trophoblastic cells were evaluated in various different sites of implantation. DNA content analysis by cytofluorometry and immunohistochemical study using a monoclonal antibody Ki-67 was performed in 5 cases with a gestation period of 8-9 weeks. The measurement of proliferative activity of trophoblastic cells was analysed in four different sites of implantation: (1) the top of the anchoring villi, (2) the cell column, (3) the intermediate trophoblasts in the decidua basalis and myometrium, and (4) the free villi. A large number of Langhans cells on the top of the anchoring villi (L-cells) were mononuclear and tetraploid. It was demonstrated that the L-cell group had 2C, 4C and 8C peaks and also had a 4C mode. S-phase fraction was also found in the L-cell group. The so-called intermediate trophoblasts (IMT) in the cell column, decidua basalis and myometrium had 2C and 4C peaks and no S-phase fraction. Ki-67 positive cells existed only in the L-cell group. The findings are as follows: 1. The L-cell group had a higher proliferative activity than the other trophoblasts. It was found to have a mononuclear tetraploidy pattern. 2. It is suspected that the cells having 4C DNA content in the IMT originated in the L-cell group. 3. In conclusion, L-cells may differentiate to syncytial trophoblasts and IMT.