Influence of administration of ovarian steroids on the function of neutrophils isolated from the blood and uterus of ovariectomized mares

Abstract

The function of blood and uterine luminal neutrophils from ovariectomized mares treated with ovarian steroids was investigated 18 h after intrauterine infusion of 1 X 10(9) Streptococcus zooepidemicus. Random migration of blood neutrophils under agarose was reduced by treatment with progesterone compared with that of neutrophils from oestradiol-treated and control mares. In-vitro addition of progesterone to blood neutrophils from acyclic ponies also reduced migration. Uterine neutrophils did not migrate under agarose which was probably an effect of bacterial phagocytosis. Hormone treatment had little effect on phagocytosis of yeast blastospores by blood neutrophils. Phagocytosis by uterine neutrophils from oestradiol-treated and control mares was significantly better than that by blood neutrophils. In progesterone-treated mares, however, phagocytosis by uterine neutrophils was significantly lower than that in the other two treatment groups and was similar to that measured in blood neutrophils. The results indicate a marked effect of progesterone in reducing both migration of blood neutrophils and phagocytosis by uterine neutrophils.

Function of Uterine and Blood-Derived Polymorphonuclear Neutrophils in Mares Susceptible and Resistant to Chronic Uterine Infection: Phagocytosis and Chemotaxis1

“…The discrepancy between those reports and the present study may be explained in part by the well-documented influence of the estrous cycle on PMN functions [23][24][25]. Consequently, it is probably inappropriate to compare experiments from different stages of the estrous cycle.…”

Assessment of Neutrophil Function in the Dairy Cow during the Perinatal Period

“…HENRICKS et al (1987) reported that the metabolic responsiveness of neutrophils is diminished and the accumulation of phagocytic cells at the site of infection is reduced after a stress period. Although studies have been reported on the effect of corticoids on leukocyte migration ( ROTH et al, 1983;WATSON et al, 1987), the results have been contradictory. Further studies are necessary to determine the exact mechanism of the effects of corticosteroids on neutrophil function.…”

What do we know about susceptibility of mares to endometritis?

“…Progesterone treatment makes previously resistant mares susceptible to bacterial challenge (Evans et al 1986, Reilas et al 1998). Although there is evidence for the adverse effects of progesterone and beneficial effects of oestrogen on PMN functions , Watson et al 1987c, the effects on the physical drainage of the uterus are much more obvious. Under the influence of progesterone the cervix is closed, whereas under oestrogen dominance it stays open.…”

“…They have been exposed to bacterial stimulation, they have responded to chemotactic stimuli, migrated and phagocytised, which changes their ability to deform. This may have changed their ability to migrate and kill bacteria (Watson et al 1987c). Many of the proposed dysfunctions for PMNs from the uterus of susceptible mares can be related to the adverse uterine luminal environment (Liu et al 1986).…”