title: HPV-16 exposed mouse embryos: a potential model for pregnancy wastage.
abstract: OBJECTIVE
  Placentas from spontaneous abortions and preterm deliveries have a higher prevalence of Human papillomavirus (HPV) compared to placentas from elective abortions and term births. The objective was to determine the effects of HPV-16 on the adhesion and implantation properties of early embryo trophoblasts.
  
  
  METHODS
  Two-cell mouse embryos were cultured (medium G2, 5 % CO2, 37 °C) for 72-96 h and exposed to either HPV-16 rich SiHa cell lysates which were refrigerated after mechanical lysis, thawed lysates which had been frozen for freeze/thaw lysis method, or control medium, incubated (4-5 days) and evaluated by microscopy (N = 96 embryos, 3 repeated experiments). Trophoblasts were stained and images were digitized. Adhesion and dimension data were analyzed by Chi-square and t test, respectively.
  
  
  RESULTS
  HPV-16 exposed embryos exhibited less adhesion through reduced implantation compared with the control (combined lysates 53.8 vs. 85.7 %, P < 0.05). Refrigerated and thawed lysate groups had similar reduced implantations (58.3 vs. 50.0 %). Of the embryos with implantation, 100 % in the refrigerated lysates were noted to have loose or abnormal adhesion. This was measured when embryos were noted to be lost after washes with HTF. There was no difference in trophoblast viability among the groups. Total trophoblast area was greater in the HPV-16 exposed frozen lysate group (1,881.8 ± 605.3 vs. control 848.8 ± 298.0 square units, mean ± SEM).
  
  
  CONCLUSIONS
  HPV-16 inhibited trophoblasts adhesion needed for normal implantation, but not embryo development. Total trophoblast spread was increased after HPV-16 exposure suggesting that HPV-16 altered trophoblast migration. These results suggest that HPV-16 may induce abnormal placental growth resulting in pregnancy wastage.
authors.affiliation: Department of Gynecology and Obstetrics, Loma Linda University School of Medicine, 11370 Anderson St., Suite 3950, Loma Linda, CA, USA. hlinda@umich.edu
authors.forename: Linda J
authors.initials: LJ
authors.lastname: Hong
authors.forename: Bryan T
authors.initials: BT
authors.lastname: Oshiro
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Chan
mesh_terms: D000022:Abortion, Spontaneous / Q000821:virology; D000818:Animals; D046149:Embryo Culture Techniques; D010064:Embryo Implantation; D004624:Embryo Transfer; D004622:Embryo, Mammalian / Q000821:virology*; D047108:Embryonic Development; D005260:Female; D052162:Human papillomavirus 16 / Q000502:physiology*; D051379:Mice; D011247:Pregnancy; D014327:Trophoblasts / Q000502:physiology / Q000821:virology