title: Peri-ovulatory putrescine supplementation reduces embryo resorption in older mice.
abstract: OBJECTIVE
  Does peri-ovulatory putrescine supplementation of older mice improve oocyte quality and reduce the incidence of embryo resorption?
  
  
  CONCLUSIONS
  Peri-ovulatory putrescine supplementation in older mice improved oocyte quality, as indicated by increased blastocyst cell numbers and reduced the incidence of embryo resorption.
  
  
  BACKGROUND
  Rodents exhibit a transient rise of ornithine decarboxylase (ODC) and putrescine in the ovaries during ovulation. Older mice exhibit reduced ovarian ODC activity during ovulation. Supplementation of in vitro maturation medium with putrescine reduces oocyte aneuploidy rates of older mice.
  
  
  METHODS
  The rationale was to correct ovarian putrescine deficiency in older mice by peri-ovulatory putrescine supplementation in drinking water and to observe the reproductive consequences of this intervention. This project was conducted between 2010 and 2014.
  
  
  METHODS
  Older mice (9-11 months of age) were given regular drinking water (control) or drinking water with 1% putrescine dihydrochloride (62 mM) for 2-4 days before mating. Plugged mice were then withdrawn from putrescine supplementation. Blastocysts were retrieved on 3.5 days post coitum (dpc) for the determination of cell numbers. For resorption analyses, mice were killed on 9.5 dp or 12.5 dpc, and implantation sites were dissected to determine the embryo status. For birth studies, mice were examined every morning between 16.5 and 23.5 dpc. Births were recorded as live or stillbirth.
  
  
  RESULTS
  We demonstrated that deficiency of ovarian putrescine in older mice can be restored by peri-ovulatory putrescine supplementation in drinking water. Putrescine supplementation in older mice increased blastocyst cell numbers (from 40 to 54; P < 0.0001, t-test), reduced embryo resorption rates (from 41.1 to 15.4% in old C57BL/6 mice, P < 0.0001, Fisher's exact test; from 14.2 to 6.4% in old CF1 mice, P = 0.004, Fisher's exact test), and doubled the number of live born pups. Furthermore, exogenous putrescine exhibited rapid absorption and excretion, and showed no toxicity to mothers or fetuses.
  
  
  CONCLUSIONS
  The mechanism of putrescine action in oocytes and/or ovaries remains unclear.
  
  
  CONCLUSIONS
  Peri-ovulatory putrescine deficiency in older mice appears to adversely impact on oocyte maturation resulting in poor quality embryos (as assessed by blastocyst cell numbers) and early embryo death. This study demonstrates a natural and simple remedy to improve oocyte quality in older women.
  
  
  BACKGROUND
  This study was supported by the NSERC, the March of Dimes Foundation, and the National Natural Science Foundation of China. The authors declare no competing interest.
authors.affiliation: Ottawa Hospital Research Institute, The Ottawa Hospital, General Campus, 501 Smyth Road, Box 511, Ottawa, ON K1H 8L6, Canada.
authors.forename: Yong
authors.initials: Y
authors.lastname: Tao
authors.affiliation: Ottawa Hospital Research Institute, The Ottawa Hospital, General Campus, 501 Smyth Road, Box 511, Ottawa, ON K1H 8L6, Canada State Key Laboratory of Reproductive Biology, Institute of Zoology, University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Liu
authors.affiliation: Ottawa Hospital Research Institute, The Ottawa Hospital, General Campus, 501 Smyth Road, Box 511, Ottawa, ON K1H 8L6, Canada Departments of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
authors.forename: Guolong
authors.initials: G
authors.lastname: Mo
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Wang
authors.affiliation: Ottawa Hospital Research Institute, The Ottawa Hospital, General Campus, 501 Smyth Road, Box 511, Ottawa, ON K1H 8L6, Canada Departments of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON K1N 6N5, Canada Department of Obstetrics and Gynecology, University of Ottawa, Ottawa, ON K1N 6N5, Canada jliu@ohri.ca.
authors.forename: X Johné
authors.initials: XJ
authors.lastname: Liu
mesh_terms: D000818:Animals; D020964:Embryo Loss / Q000517:prevention & control*; D005260:Female; D051379:Mice; D008810:Mice, Inbred C57BL; D009865:Oocytes / Q000187:drug effects*; D010060:Ovulation / Q000187:drug effects*; D011247:Pregnancy; D011700:Putrescine / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D011700:Putrescine
keywords: aging; embryo resorption; oocyte maturation; ovulation; putrescine