Regulation Of Ifn-τ Expression In Bovine Trophoblast Cell By Progesterone And Estradiol

Interferon-tau(IFN-τ)is synthesized and secreted specifically by trophoblast cells of the peri-implantation ruminant fetus and has a key role in the fetal-maternal interactions, pregnant recognition and uterine receptivity for implantation. It can inhibit corpus luteum periodic dissolution, promote the development of corpus luteum. Currently, there is no clear definition as to the mechanism about expression and regulation of IFN-τ.At the commencement of this study, in order to provide evidence for the following hormone interventions experiment, it is necessary to assay progesterone (P4) and estradiol (E2) level in blood of the holstein cow at whole pregnant cycle by ELISA. Secondly, trophoblast cell were isolated from parthenogenesis activation embryos and cultured in SOF-BE1mediun supplemented with20%FBS and lOng/mL EGF at37℃in air with5%CO2. Finally intervened the trophoblast by P4and E2. Intervention programs in two steps:1. Designed a3×3(concentration, time) two-factor experiment, the intervened concentration of P4were divided into three group, group Ⅰ2.5pg/mL group Ⅱ5pg/mL, group Ⅲ10pg/mL. the intervened concentration of E2were divided into three group, group Ⅰ10pg/mL, group Ⅱ25pg/mL, group III50pg/mL. The reaction times of each group were3h,12h and24h.2. The three concentrations of P4and E2were permutated and combined each by each, and divided into9groups. The trophoblast cells reaction time is24h. Real-time PCR was used to to detect the IFN-τ expression in trophoblast cell.The results showed that, after fertilization, the P4in vivo continued to increase up to around2ng at day20and maintained until240days; estradiol declining to20pg after20days and sustaining at20pg to about45days, followed by further decline and maintain around10pg to240days, while in the prenatal estradiol raised above the level of early pregnancy. Trophoblast cells were well cultured in a humidified atmosphere of5%CO2,20%FBS and SOF-BE1medium at37℃. P4alone can significantly promoted IFN-τ expression in trophoblastic in12h,24h of group P4Ⅲ, whereas the difference of other groups was not significant. When E2alone in trophoblast cells, group Ⅱ12h,24h and group Ⅲ,12h,24h dramatically inhibit the expression of IFN-τ dramatically while the inhibition of group Ⅰ24h was significant but not as good as above.There was a promote expression effect when both P4and E2worked in trophoblast cells, and considerable differences can be found contrast with control group:group P4ⅢE2Ⅱ was the highest number,7times as much as control group. The intervention effect of P4, E2dual hormone are better than P4alone, it can reverse the inhibition effect that E2worked on IFN-τ expression.It was shown that the result of interfere effect was positively correlated with P4concentration.Conclusion:the establishment of embryos trophoblastic cells model in vitro for research on IFN-τ is operable and convenient and this model provides a study platform for IFN-τ. The result shows that P4can significantly up-regulate IFN-τ expression, whereas E2depress IFN-τ expression in trophoblast cell. However, P4, E2together simulate hormone levels in vivo was significantly to increase the expression of IFN-τ in trophoblast cell. This suggesting IFN-τ expression in peri-implantation period could be regulated by the joint action of P4and E2.