title: Analysis of the phospholipid profile of metaphase II mouse oocytes undergoing vitrification.
abstract: Oocyte freezing confers thermal and chemical stress upon the oolemma and various other intracellular structures due to the formation of ice crystals. The lipid profiles of oocytes and embryos are closely associated with both, the degrees of their membrane fluidity, as well as the degree of chilling and freezing injuries that may occur during cryopreservation. In spite of the importance of lipids in the process of cryopreservation, the phospholipid status in oocytes and embryos before and after freezing has not been investigated. In this study, we employed mass spectrometric analysis to examine if vitrification has an effect on the phospholipid profiles of mouse oocytes. Freshly prepared metaphase II mouse oocytes were vitrified using copper grids and stored in liquid nitrogen for 2 weeks. Fresh and vitrified-warmed oocytes were subjected to phospholipid extraction procedure. Mass spectrometric analyses revealed that multiple species of phospholipids are reduced in vitrified-warmed oocytes. LIFT analyses identified 31 underexpressed and 5 overexpressed phospholipids in vitrified mouse oocytes. The intensities of phosphatidylinositol (PI) {18∶2/16∶0} [M-H]- and phosphatidylglycerol (PG) {14∶0/18∶2} [M-H]- were decreased the most with fold changes of 30.5 and 19.1 in negative ion mode, respectively. Several sphingomyelins (SM) including SM {d38∶3} [M+H]+ and SM {d34∶0} [M+K]+ were decreased significantly in positive ion mode. Overall, the declining trend of multiple phospholipids demonstrates that vitrification has a marked effect on phospholipid profiles of oocytes. These results show that the identified phospholipids can be used as potential biomarkers of oocyte undergoing vitrification and will allow for the development of strategies to preserve phospholipids during oocyte cryopreservation.
authors.affiliation: Department of Pharmacology, Konkuk University School of Medicine, Seoul, Korea; Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Gyeonggi-do, Korea.
authors.forename: Jaehun
authors.initials: J
authors.lastname: Jung
authors.affiliation: Department of Biomedical Science & Technology, Institute of Biomedical Science & Technology, Konkuk University, Seoul, Korea.
authors.forename: Hyejin
authors.initials: H
authors.lastname: Shin
authors.affiliation: Department of Biomedical Science & Technology, Institute of Biomedical Science & Technology, Konkuk University, Seoul, Korea.
authors.forename: Soyoung
authors.initials: S
authors.lastname: Bang
authors.affiliation: Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Gyeonggi-do, Korea.
authors.forename: Hyuck Jun
authors.initials: HJ
authors.lastname: Mok
authors.affiliation: Department of Obstetrics and Gynecology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Chang Suk
authors.initials: CS
authors.lastname: Suh
authors.affiliation: Department of Applied Chemistry, College of Applied Science, Kyung Hee University, Yongin, Gyeonggi-do, Korea.
authors.forename: Kwang Pyo
authors.initials: KP
authors.lastname: Kim
authors.affiliation: Department of Biomedical Science & Technology, Institute of Biomedical Science & Technology, Konkuk University, Seoul, Korea.
authors.forename: Hyunjung Jade
authors.initials: HJ
authors.lastname: Lim
mesh_terms: D000818:Animals; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D008677:Metaphase / Q000502:physiology; D051379:Mice; D008813:Mice, Inbred ICR; D054315:Oocyte Retrieval; D009865:Oocytes / Q000502:physiology*; D010743:Phospholipids / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D058989:Vitrification
chemical_list: D010743:Phospholipids