title: Impact of anisosmotic conditions on structural and functional integrity of cumulus-oocyte complexes at the germinal vesicle stage in the domestic cat.
abstract: During cryopreservation, the immature oocyte is subjected to anisosmotic conditions potentially impairing subsequent nuclear and cytoplasmic maturation in vitro. In preparation for cryopreservation protocols and to characterize osmotic tolerance, cat cumulus-oocyte complexes (COC) at the germinal vesicle (GV) stage were exposed for 15 min to sucrose solutions ranging from 100 to 2,000 mOsm and then examined for structural integrity and developmental competence in vitro. Osmolarities > or =200 and < or =750 mOsm had no effect on incidence of oocyte nuclear maturation, fertilization success, and blastocyst formation compared to control COC (exposed to 290 mOsm). This relatively high osmotic tolerance of the immature cat oocyte appeared to arise from a remarkable stability of the GV chromatin structure as well as plasticity in mitochondrial distribution, membrane integrity, and ability to maintain cumulus-oocyte communications. Osmolarities <200 mOsm only damaged cumulus cell membrane integrity, which contributed to poor nuclear maturation but ultimately had no adverse effect on blastocyst formation in vitro. Osmolarities >750 mOsm compromised nuclear maturation and blastocyst formation in vitro via disruption of cumulus-oocyte communications, an effect that could be mitigated through 1,500 mOsm by adding cytochalasin B to the hyperosmotic solutions. These results (1) demonstrate, for the first time, the expansive osmotic tolerance of the immature cat oocyte, (2) characterize the fundamental role of cumulus-oocyte communications when tolerance limits are exceeded, and (3) reveal an interesting hyperosmotic tolerance of the immature oocyte that can be increased two-fold by supplementation with cytochalasin B.
authors: Center for Species Survival, Department of Reproductive Sciences, Smithsonian's National Zoological Park, Washington, District of Columbia 20008-2598, USA. comizzolip@si.edu
authors: Pierre
authors: P
authors: Comizzoli
authors: David E
authors: DE
authors: Wildt
authors: Budhan S
authors: BS
authors: Pukazhenthi
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology / Q000502:physiology; D002415:Cats; D018929:Cell Culture Techniques; D002467:Cell Nucleus / Q000502:physiology; D054885:Cumulus Cells / Q000166:cytology* / Q000502:physiology*; D047108:Embryonic Development; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D008297:Male; D009865:Oocytes / Q000166:cytology* / Q000502:physiology*; D009994:Osmolar Concentration; D010052:Ovariectomy; D010053:Ovary / Q000502:physiology; D013081:Sperm Motility; D013094:Spermatozoa / Q000502:physiology
references: Reprod Domest Anim. 2004 Apr;39(2):70-5
references: 15065986
references: Reproduction. 2003 Dec;126(6):809-16
references: 14748700
references: Cryobiology. 2004 Jun;48(3):341-8
references: 15157782
references: Biol Reprod. 2004 Aug;71(2):598-604
references: 15084479
references: Hum Reprod. 1992 Nov;7(10):1440-6
references: 1291574
references: Cryobiology. 1994 Apr;31(2):154-70
references: 8004996
references: Cryobiology. 1997 Feb;34(1):23-35
references: 9028914
references: Mol Reprod Dev. 1997 Oct;48(2):208-15
references: 9291470
references: J Reprod Fertil. 1997 Jul;110(2):355-60
references: 9306990
references: Cryobiology. 1998 May;36(3):250-3
references: 9597744
references: Biol Reprod. 1998 Aug;59(2):395-400
references: 9687313
references: Biol Reprod. 1999 Jul;61(1):188-94
references: 10377048
references: Reproduction. 2004 Dec;128(6):703-8
references: 15579587
references: Eur J Histochem. 2004 Oct-Dec;48(4):337-46
references: 15718199
references: Mol Reprod Dev. 2005 Jul;71(3):389-97
references: 15803456
references: Mol Reprod Dev. 2005 Jul;71(3):358-67
references: 15822117
references: Reprod Biomed Online. 2005 May;10(5):578-86
references: 15949213
references: Reprod Fertil Dev. 2006;18(1-2):77-90
references: 16478605
references: Biol Reprod. 2006 Mar;74(3):585-92
references: 16280415
references: Cryobiology. 2006 Apr;52(2):219-27
references: 16388794
references: Theriogenology. 2006 Jul 1;66(1):101-11
references: 16620937
references: Reproduction. 2006 Jul;132(1):119-31
references: 16816338
references: Fertil Steril. 2006 Jul;86(1):70-80
references: 16818031
references: Theriogenology. 2006 Sep 1;66(4):955-63
references: 16574209
references: Mol Reprod Dev. 2006 Nov;73(11):1454-62
references: 16894553
references: Anim Reprod Sci. 2006 Nov;96(1-2):66-78
references: 16386859
references: Mol Reprod Dev. 2007 Jun;74(6):740-9
references: 17075796
references: J Reprod Fertil. 1999 Sep;117(1):27-33
references: 10645242
references: Mol Reprod Dev. 2000 Feb;55(2):212-9
references: 10618661
references: Mol Reprod Dev. 2006 May;73(5):617-26
references: 16450409
references: Biol Reprod. 2000 May;62(5):1177-83
references: 10775164
references: Theriogenology. 2000 May;53(8):1529-40
references: 10883841
references: ILAR J. 2000;41(4):228-34
references: 11123183
references: Proc Natl Acad Sci U S A. 2001 Feb 13;98(4):1999-2004
references: 11172065
references: Hum Reprod. 2001 Mar;16(3):411-6
references: 11228204
references: Biol Reprod. 2001 Mar;64(3):904-9
references: 11207207
references: Reproduction. 2001 Oct;122(4):619-28
references: 11570969
references: J Reprod Fertil Suppl. 2001;57:141-6
references: 11787141
references: Hum Reprod. 2002 Feb;17(2):393-406
references: 11821285
references: J Cell Sci. 2002 Jun 1;115(Pt 11):2433-42
references: 12006627
references: Dev Biol. 2002 Jun 15;246(2):441-54
references: 12051828
references: Hum Reprod. 2002 Jul;17(7):1875-84
references: 12093854
references: Mol Reprod Dev. 2002 Dec;63(4):464-70
references: 12412049
references: Hum Reprod. 2003 Feb;18(2):392-8
references: 12571179
references: Mol Reprod Dev. 2003 Apr;64(4):458-70
references: 12589658
references: Cryobiology. 2003 Aug;47(1):1-13
references: 12963407
references: Reprod Suppl. 2003;61:49-54
references: 14635926
references: Exp Cell Res. 2004 Jan 15;292(2):304-11
references: 14697338
references: Biol Reprod. 2004 Feb;70(2):465-72
references: 14568913
references: Hum Reprod. 2004 May;19(5):1148-54
references: 15070883