Dose related effects of LPS on endometrial epithelial cell populations from dioestrus cows

• The number of immune cells in endometrial tissue samples increased with age.
• The labelling of marker of proliferation Ki67 differed between estrous cycle stage.
• Cell populations in vitro were not affected by tissue sample or cow related factors.
• 8 μg/mL LPS increases numbers of bovine endometrial epithelial cells in vitro.
• Higher dosages of LPS decreases in vitro cell proliferation and viability.

Lipopolysaccharides (LPS) from Gram negative bacteria are involved in the pathogeny of uterine diseases in cows. This study aimed to investigate LPS effects on the growth of bovine endometrial epithelial cells (bEEC) and relationships between LPS response and tissue characteristics. Uteri from 35 females were characterized for parity and stage of oestrous cycle. Densities of glandular tissue (dGT), CD11b+ cells and Ki67+ cells were measured in the endometrial tissue. Cells from 13 dioestrus cows were exposed to 0, 2, 4, 8, 12, 16 or 24 μg/mL LPS. Effects of parity and stage of the oestrous cycle on tissue characteristics and effects of LPS dosage, cow and tissue characteristics on changes in cell numbers were analyzed by ANOVA. The dGT was higher in metoestrus and dioestrus samples than in pro-oestrus ones whereas densities of CD11b+ and Ki67+ cells were higher at pro-oestrus (p < 0.05–p < 0.01). LPS influenced bEEC populations in a dose related manner. An increase in number of live cells was observed for dosages ranging from 2 to 12 μg/mL LPS (p < 0.0001 vs controls). No effect was found on numbers and frequencies of dead cells. With higher dosages, the numbers of live cells did not increase but the numbers of dead did increase. No relationships were observed between cow or tissue characteristics and growth patterns or frequencies of viable bEEC in controls nor in the response to LPS. To conclude this model is suitable for further studies on dysregulations induced by LPS in endometrial tissue.