Chemotactic properties and protein of equine uterine fluid

Forty uterine fluid samples were obtained from 4 mares classified as resistant to uterine bacterial infection. The uterus of each mare was flushed with 50 ml of saline solution during estrus and diestrus of successive estrous cycles. Bacteria or fungi were isolated from 4 samples, and 7 additional samples were obtained from a mare with active intrauterine infection. Fluid volumes obtained during estrus (means = 40.3 +/- 11 ml) tended to be greater than those recovered during diestrus (means = 36.8 +/- 7.9 ml), but the difference was not significant. Concentrations and yields of protein in recovered fluid did not vary significantly with the day of the estrous cycle. Protein concentration was significantly increased in samples from the infected uterus (P = less than 0.001). The ability of uterine fluid samples to attract neutrophils was measured using chemotactic chambers. There was no significant difference between distances migrated by neutrophils toward fluids obtained during estrus or diestrus. Chemotaxis scores tended to be higher with samples from the infected uterus, and the difference was significant for samples from 2 mares. Chemotaxis was neither significantly correlated with protein concentration of uterine fluid, nor with serum estrogens or progesterone.