title: Cytokeratin distribution and expression during the maturation of mouse germinal vesicle oocytes after vitrification.
abstract: Cytokeratin (CK) is a type of the cytoskeleton that increases cell stabilization during oocyte maturation. This study was conducted to investigate the effect of vitrification on the distribution and expression of CK during mouse oocyte maturation. Germinal vesicle (GV) oocytes were randomly allocated into three groups: (1) untreated (fresh), (2) exposed to vitrification solution (VS) without being plunged into liquid nitrogen (CPA exposure), or (3) vitrified using the open-pulled straw (OPS) method (vitrification). The oocytes were then incubated for 0 h, 6h (metaphase I (MI) stage), and 10h (metaphase II (MII) stage). The CK distribution in the oocytes at the GV, MI, and MII stages was observed by immunofluorescence, and the expression at the MII stage oocytes derived from vitrified GV oocytes was detected by Western blotting. The CK distribution in the GV oocytes (88.5%) displayed a cortical pattern in the fresh group, whereas a granular pattern was mainly found at the MI (86.7%) and MII (93.5%) stages. In the CPA exposure group, 90.3% of the GV oocytes were observed to display the cortical pattern, and 69.2% of the MI oocytes and 92.9% of the MII oocytes showed the granular pattern. In the vitrification group, most oocytes (GV, 88.9%; MI, 100%; MII, 93.3%) exhibited the cortical pattern. The CK fluorescence intensities of the MII stage oocytes in both the fresh (59.27) and CPA exposure (60.05) group were significantly higher than that of the vitrification (26.53) group (p<0.05). Western blotting showed that the CK expression in the MII oocytes derived from vitrified GV oocytes was significantly lower (p<0.05) than in the control. In conclusion, OPS vitrification affects the normal CK distribution pattern during oocyte maturation and results in decreased CK expression in MII oocytes derived from vitrified GV oocytes.
authors.affiliation: National Engineering Laboratory for Animal Breeding, Key Laboratory of Animal Genetics, Breeding and Reproduction, Ministry of Agriculture, College of Animal Science and Technology, China Agricultural University, Beijing 100193, PR China.
authors.forename: Xia
authors.initials: X
authors.lastname: Wei
authors.forename: Fu
authors.initials: F
authors.lastname: Xiangwei
authors.forename: Zhou
authors.initials: Z
authors.lastname: Guangbin
authors.forename: Xu
authors.initials: X
authors.lastname: Jing
authors.forename: Wang
authors.initials: W
authors.lastname: Liang
authors.forename: Du
authors.initials: D
authors.lastname: Ming
authors.forename: Yuan
authors.initials: Y
authors.lastname: Dianshuai
authors.forename: Yue
authors.initials: Y
authors.lastname: Mingxing
authors.forename: Tian
authors.initials: T
authors.lastname: Jianhui
authors.forename: Zhu
authors.initials: Z
authors.lastname: Shien
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002470:Cell Survival; D002478:Cells, Cultured; D015925:Cryopreservation / Q000379:methods*; D005260:Female; D007633:Keratins / Q000032:analysis* / Q000378:metabolism; D008677:Metaphase; D051379:Mice; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D009866:Oogenesis; D011897:Random Allocation; D058989:Vitrification
chemical_list: D007633:Keratins