title: Hydroxyapatite nanoparticles improved survival rate of vitrified porcine oocytes and its mechanism.
abstract: BACKGROUND
  Cryopreservation of oocyte has become most essential for the long-term conservation and widespread dispersion of animal genetic resources, but the efficiency of oocyte cryopreservation remains low.
  
  
  OBJECTIVE
  The present study is to study the effect of hydroxyapatite (HA) nanoparticles on the survival rate of vitrified oocytes and the possible mechanism of cryopreserving oocytes with nanoparticles.
  
  
  METHODS
  Porcine oocytes were vitrified in cryoprotectant (CPA) with biocompatible HA nanoparticles by Cryotop. The recrystallization of nano-CPA was observed with cryomicroscope.
  
  
  RESULTS
  When 0.01%, 0.02%, 0.05% and 0.1% HA nanoparticles were added into vitrification solution, the survival rate of oocytes after in vitro maturation ranged from 25.9% to 35.4%, which is significantly higher than group without HA nanoparticles (14.7%). The microphotographs of oocytes in different solutions during freezing, thawing and melting showed that HA nanoparticles at a certain concentration can hinder the recrystallization of vitrification solution during rewarming.
  
  
  CONCLUSIONS
  We speculate that preventing the recrystallization is the reason that nano-CPA can promote the survival rate of vitrified oocytes.
authors.forename: Xinli
authors.initials: X
authors.lastname: Zhou
authors.forename: Weijie
authors.initials: W
authors.lastname: Li
authors.forename: Defu
authors.initials: D
authors.lastname: Zhang
authors.forename: Jianjun
authors.initials: J
authors.lastname: Dai
mesh_terms: D000818:Animals; D002470:Cell Survival; D015925:Cryopreservation / Q000379:methods* / Q000662:veterinary*; D003460:Crystallization; D017886:Durapatite / Q000737:chemistry*; D005260:Female; D053758:Nanoparticles / Q000737:chemistry*; D009865:Oocytes / Q000166:cytology*; D013552:Swine / Q000378:metabolism; D058989:Vitrification
chemical_list: D017886:Durapatite