Development of an in vitro model for the analysis of bovine endometrium using simple techniques

This study aimed to develop an in vitro model for the analysis of the bovine endometrium. Immunofluorescent staining revealed that the hetero-spheroids and the cultured explants showed almost similar structure in the localization of bovine endometrial epithelial cells and endometrial stromal cells, except the glandular-like structure of the epithelial cells inside the explants. Gelatin zymography revealed that the hetero-spheroids did not express matrix metalloproteinases (MMPs) after 4 days of culture, but strong MMP expressions were observed in the cultured explants until 7 days of culture. Additionally, expression of progesterone receptor (PR), estrogen receptor alpha (ERα), type I interferon receptor 1 (IFNAR1) and 2 (IFNAR2) messenger RNA was observed both in the homo- and hetero-spheroids. The expression of oxytocin receptor (OTR) mRNA in E2 and E2+P4 (1,3,5(10)-Estratrien-3, 17β-diol + 4-Pregnen-3, 20-dinone) treated groups were significantly (P < 0.05) higher than that of the control group of spheroids. In case of cultured explants, the expression of PR and OTR mRNA were significantly (P < 0.05) higher in E2 treated groups compared to the control groups. Hepatocyte growth factor (HGF) mRNA expression was also higher in P4 treated groups at 10 days in culture (P < 0.05). In a nutshell, the in vitro model developed in this study for the analysis of the endometrium may provide a new platform for extensive research on bovine endometrial function.