The effect of spermatozoa and seminal plasma on leukocyte migration into the uterus of gilts

Yorkshire x Landrace gilts were used to determine the effect of spermatozoa and seminal plasma on postbreeding uterine leukocyte influx. Estrus detect ion was performed with a boar at 12-h intervals following synchronization w ith 400 IU eCG and 200 IU of hCG. All gilts were Al once, 24 h after the de tection of estrus following random assignment to a 2 x 2 x 3 factorial arra ngement of treatments (sperm or sperm-free AI doses), Al dose medium (semin al plasma or PBS), and lavage time following Al. Gilts were treated with sp erm (5 x 10(9) spermatozoa; SPZ; n = 30) or sperm-free (SF; n = 30) doses c ontaining either 100 mt of seminal plasma (SP; n = 15/treatment) or PBS (n = 15/treatment). Uterine lavage was performed once on each gilt (n 20/time) at one of three times after AI (6, 12, or 36 h) to determine the total num ber of uterine leukocytes. The leukocytes consisted predominately (92 to 99 %) of polymorphonuclear neutrophilic granulocytes (PMN). There was an AI x medium interaction on uterine PMN numbers. The number of uterine PMN recove red from gilts inseminated with sperm suspended in PBS was greater than the number of PMN recovered from the uterine lumen of gilts inseminated with s perm in SP, SP alone, or PBS alone (P < .05). Furthermore, SP accelerated t he rate of uterine clearance when suspended with sperm cells during the fir st 36 h following Al (P < .05);. These results indicate that seminal plasma suppresses PMN migration into the uterus following breeding and enhances t he rate of disappearance of uterine inflammation.