title: Evidence that polymorphonuclear neutrophils infiltrate into the developing corpus luteum and promote angiogenesis with interleukin-8 in the cow.
abstract: BACKGROUND
  After ovulation in the cow, the corpus luteum (CL) rapidly develops within a few days with angiogenesis and progesterone production. CL formation resembles an inflammatory response due to the influx of immune cells. Neutrophils play a role in host defense and inflammation, and secrete chemoattractants to stimulate angiogenesis. We therefore hypothesized that neutrophils infiltrate in the developing CL from just after ovulation and may play a role in angiogenesis of the CL.
  
  
  RESULTS
  Polymorphonuclear neutrophils (PMN) were detected in CL tissue by Pas-staining, and interleukin-8 (IL-8, a neutrophil-specific chemoattractant) was measured in supernatant of the CL tissue culture: considerable amounts of PMNs and the high level of IL-8 were observed during the early luteal phase (days 1-4 of the estrous cycle). PMNs and IL-8 were low levels in the mid and late luteal phases, but IL-8 was increased during luteal regression. The PMN migration in vitro was stimulated by the supernatant from the early CL but not from the mid CL, and this activity was inhibited by neutralizing with an anti-IL-8 antibody, indicating the major role of IL-8 in inducing active PMN migration in the early CL. Moreover, IL-8 stimulated proliferation of CL-derived endothelial cells (LECs), and both the supernatant of activated PMNs and IL-8 stimulated formation of capillary-like structures of LECs.
  
  
  CONCLUSIONS
  PMNs migrate into the early CL partially due to its major chemoattractant IL-8 produced at high levels in the CL, and PMNs is a potential regulator of angiogenesis together with IL-8 in developing CL in the cow.
authors.affiliation: Graduate School of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro 080-8555, Japan.
authors.forename: Sineenard
authors.initials: S
authors.lastname: Jiemtaweeboon
authors.forename: Koumei
authors.initials: K
authors.lastname: Shirasuna
authors.forename: Akane
authors.initials: A
authors.lastname: Nitta
authors.forename: Ayumi
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Schuberth
authors.forename: Takashi
authors.initials: T
authors.lastname: Shimizu
authors.forename: Akio
authors.initials: A
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D002417:Cattle / Q000276:immunology / Q000502:physiology; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D003338:Corpus Luteum / Q000187:drug effects / Q000254:growth & development* / Q000276:immunology / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism / Q000502:physiology; D005260:Female; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D008184:Luteal Cells / Q000378:metabolism / Q000502:physiology; D008183:Luteal Phase / Q000235:genetics / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D018919:Neovascularization, Physiologic / Q000187:drug effects / Q000502:physiology; D009504:Neutrophils / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D016209:Interleukin-8; D012333:RNA, Messenger