Differential localization of decidual stathmin during pregnancy in rats

The present study was undertaken to determine the precise localization of stathmin, a protein associated with microtubule dynamics, during decidualization in rat uterus and to compare it with that of cyclin D3. Immunohistochemical analysis revealed that stathmin is exclusively localized in decidual cells, especially in the primary decidual zone surrounding the embryo, on days 7 and 9 of pregnancy. The intensity of staining was much higher on day 9 than day 7. On day 14, when the endometrial stromal cells had completely differentiated into decidual cells, the staining of decidual cells was faint. Cyclin D3 was expressed in decidual cells of the secondary but not the primary decidual zone on days 7 and 9. On day 14, cyclin D3 levels were low in decidua. Proliferating cell nuclear antigen (PCNA) was broadly detected in the uterus on days 7 and 9, and in the placenta and fetus on day 14. In an artificial decidualization model, cyclin D3 expression was stimulated as deciduoma was formed after an artificial stimulus. Stathmin mRNA levels also increased within 24 h and peaked at 48 h. The specific spatio-temporal uterine expression of stathmin and cyclin D3 suggest that they have a specific role in decidualization in rats.