Expression of insulin-like growth factor-binding protein-1 (IGFBP-1) mRNA in embryos and endometrial stromal cells

The objective of the present study was to investigate the effects of insulin-like growth factor-binding protein-1 (IGFBP-1) on the interaction between mouse embryos and endometrial stromal cells in co-culture systems. To explore quantitatively the changes in expression of IGFBP-1 mRNA from endometrial stromal cells cultured alone or co-cultured with embryos, a combination of reverse transcription-polymerase chain reaction (RT-PCR) and Southern blotting followed by a densitometric analysis was used. In co-culture systems, development of embryos was significantly improved and the production of IGFBP-1 from endometrial stromal cells was stimulated by the embryos. Quantitative analysis showed that expression of IGFBP-1 mRNA in endometrial stromal cells co-cultured with embryos was higher on days 3,5 and 8 (1.6-, 4.5- and 2.3-fold respectively) than in endometrial stromal cells cultured alone. In addition, intensity of PCR products for IGFBP-1 mRNA in endometrial stromal cells co-cultured with embryos was higher on day 5 than on days 3 and 8. However, the expression of IGFBP-1 mRNA in embryos cultured alone was very low. In conclusion, co-culture of embryos with endometrial stromal cells improved the development of embryos and may be associated with the production of IGFBP-1 by the co-cultured endometrial stromal cells. A combination of RT-PCR and Southern blotting followed by a densitometric analysis appeared to be a sufficiently quantitative method to determine changes in IGFBP-1 mRNA values.