抄録
The oviduct supplies a suitable microenvironment for sperm capacitation and fertilization. Pathogens and endotoxins can invade the oviduct via the uterus, peritoneal cavity and follicular fluid. We recently showed that bovine oviduct epithelial cells(BOEC) keenly respond to proinflammatory stimulus thereby regulating the balance of Th1 and Th2 cytokines. We describe here a novel local production of AGP, a major acute phase protein mainly secreted from the liver, in bovine oviduct, and the existence of PMN in oviduct fluid at high concentration. The aim of the present study is to investigate 1) PMN in oviduct fluid, 2) IL-8 expression, a major chemoattractant to PMN, in the oviduct by IHC, 3) a local production of AGP in BOEC, 4) the action of AGP on BOEC in regulating Th1 vs. Th2 balancing, and 5) a direct effect of AGP on PMN phagocytosis to the capacitated sperm. PMN were found in oviduct fluid and oviduct tissue as confirmed with histology and Giemsa staining. Number of PMN in oviduct fluid was stable over the estrous cycle. IL-8 was intensively stained in BOEC of ampulla, but lesser in isthmus. AGP was detected by ELISA in the oviduct fluid and BOEC culture supernatant at concentration of 10% of serum. In BOEC culture, AGP (1–1000 ng/ml) induced mRNA for Th2 cytokines IL-4 and IL-10 whereas inhibited Th1 cytokine TNFa. Moreover, AGP (1–100 ng/ml) dose-dependently suppressed PMN phagocytosis to capacitated sperm in vitro. Overall, the findings strongly suggest that PMN migrate into the oviduct fluid by IL-8, and that a local produced AGP in the oviduct induces Th2 balancing in BOEC, and directly inhibits PMN phagocytosis to sperm, indicating a novel role of AGP in oviduct physiology.
