Abstract
To establish a storage system for isolated endometrial cells, we investigated the basal, oxytocin (OT)- and tumor necrosis factor (TNF) α-stimulated production of prostaglandin (PG) F2α in bovine-passaged and frozen-thawed endometrial cells. Stromal and epithelial cells obtained from cows in the early stage of the estrous cycle (Days 2-5) were frozen at -80 C or further cultured and/or passaged until passage 4 in DMEM/Ham's F-12 supplemented with 10% calf serum. A fresh-unfrozen primary culture and one-time passaged fresh-unfrozen cells were used as the control. When both unfrozen and frozen cells reached confluence, the culture medium was replaced with fresh medium with 0.1% BSA and the cells were stimulated with OT (100 ng/ml) or TNFα (1 ng/ml) for 4 h. The passage and freezing of the endometrial cells did not affect their morphology. In primary culture of frozen and unfrozen endometrial cells, OT strongly stimulated PGF2α production in epithelial cells, and TNFα strongly stimulated PGF2α production in stromal cells (P<0.05). The basal output of PGF2α in frozen stromal cells was similar to that in unfrozen stromal cells. However, the basal output of PGF2α in frozen epithelial cells was significantly lower than that unfrozen cells (P<0.05). On the other hand, in passaged cells, the basal level of PGF2α production was retained until passage 1 in epithelial cells, whereas it was retained until passage 4 in stromal cells. Although epithelial cells responded to OT in PGF2α production until passage 2 (P<0.05), the stromal cells showed a significant response to TNFα until passage 4 (P<0.05). These results suggest that stored cells could be used for studying the physiology of bovine endometrium in vitro until passage 1 in endometrial epithelial cells, and until passage 4 in stromal cells.
