Abstract
Fertilization at increased times after ovulation is associated with poor reproductive outcomes. This study examines the effects of post-ovulatory ageing on egg membrane function through analyses of mouse eggs collected at 13 and 22h post-HCG ('young' and 'aged' eggs, respectively). Experiments in which fertilized zona pellucida-free young and aged eggs are challenged with additional sperm reveal that aged eggs are less able to establish a membrane block to prevent polyspermy, since sperm penetrate 24% of fertilized aged eggs but are unable to penetrate fertilized young eggs. This is not due to a failure of aged eggs to respond to fertilization, as the extent of sperm-induced cortical granule exocytosis is similar in aged and young eggs. Post-ovulatory ageing also affects egg membrane receptivity to sperm as a subset of zona pellucida-free aged eggs are slow to fertilize or resistant to fertilization. Sperm binding to young and aged eggs is similar, but aged eggs develop cytoskeletal abnormalities that may affect membrane/cortical function, such as the ability of the egg membrane to support sperm-egg fusion. These data demonstrate that the poor reproductive outcomes associated with post-ovulatory ageing could be a result of reduced fertilization, due to reduced egg membrane receptivity to sperm, or a result of increased incidence of polyspermy, due to the reduced ability to establish a membrane block to polyspermy. This analysis of egg membrane function deficiencies provides insights into post-ovulatory ageing and has implications for assisted reproductive technologies.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1-9 |
| Number of pages | 9 |
| Journal | Molecular Human Reproduction |
| Volume | 11 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2005 |
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Keywords
- Actin
- Cytoskeleton
- Egg activation
- Polyspermy
- Post-ovulatory ageing
ASJC Scopus subject areas
- Obstetrics and Gynecology
- Genetics
- Developmental Biology
- Embryology
- Cell Biology
Cite this
Membrane and cortical abnormalities in post-ovulatory aged eggs : Analysis of fertilizability and establishment of the membrane block to polyspermy. / Wortzman, Genevieve B.; Evans, Janice Perry.
In: Molecular Human Reproduction, Vol. 11, No. 1, 01.2005, p. 1-9.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Membrane and cortical abnormalities in post-ovulatory aged eggs
T2 - Analysis of fertilizability and establishment of the membrane block to polyspermy
AU - Wortzman, Genevieve B.
AU - Evans, Janice Perry
PY - 2005/1
Y1 - 2005/1
N2 - Fertilization at increased times after ovulation is associated with poor reproductive outcomes. This study examines the effects of post-ovulatory ageing on egg membrane function through analyses of mouse eggs collected at 13 and 22h post-HCG ('young' and 'aged' eggs, respectively). Experiments in which fertilized zona pellucida-free young and aged eggs are challenged with additional sperm reveal that aged eggs are less able to establish a membrane block to prevent polyspermy, since sperm penetrate 24% of fertilized aged eggs but are unable to penetrate fertilized young eggs. This is not due to a failure of aged eggs to respond to fertilization, as the extent of sperm-induced cortical granule exocytosis is similar in aged and young eggs. Post-ovulatory ageing also affects egg membrane receptivity to sperm as a subset of zona pellucida-free aged eggs are slow to fertilize or resistant to fertilization. Sperm binding to young and aged eggs is similar, but aged eggs develop cytoskeletal abnormalities that may affect membrane/cortical function, such as the ability of the egg membrane to support sperm-egg fusion. These data demonstrate that the poor reproductive outcomes associated with post-ovulatory ageing could be a result of reduced fertilization, due to reduced egg membrane receptivity to sperm, or a result of increased incidence of polyspermy, due to the reduced ability to establish a membrane block to polyspermy. This analysis of egg membrane function deficiencies provides insights into post-ovulatory ageing and has implications for assisted reproductive technologies.
AB - Fertilization at increased times after ovulation is associated with poor reproductive outcomes. This study examines the effects of post-ovulatory ageing on egg membrane function through analyses of mouse eggs collected at 13 and 22h post-HCG ('young' and 'aged' eggs, respectively). Experiments in which fertilized zona pellucida-free young and aged eggs are challenged with additional sperm reveal that aged eggs are less able to establish a membrane block to prevent polyspermy, since sperm penetrate 24% of fertilized aged eggs but are unable to penetrate fertilized young eggs. This is not due to a failure of aged eggs to respond to fertilization, as the extent of sperm-induced cortical granule exocytosis is similar in aged and young eggs. Post-ovulatory ageing also affects egg membrane receptivity to sperm as a subset of zona pellucida-free aged eggs are slow to fertilize or resistant to fertilization. Sperm binding to young and aged eggs is similar, but aged eggs develop cytoskeletal abnormalities that may affect membrane/cortical function, such as the ability of the egg membrane to support sperm-egg fusion. These data demonstrate that the poor reproductive outcomes associated with post-ovulatory ageing could be a result of reduced fertilization, due to reduced egg membrane receptivity to sperm, or a result of increased incidence of polyspermy, due to the reduced ability to establish a membrane block to polyspermy. This analysis of egg membrane function deficiencies provides insights into post-ovulatory ageing and has implications for assisted reproductive technologies.
KW - Actin
KW - Cytoskeleton
KW - Egg activation
KW - Polyspermy
KW - Post-ovulatory ageing
UR - http://www.scopus.com/inward/record.url?scp=14744305131&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=14744305131&partnerID=8YFLogxK
U2 - 10.1093/molehr/gah125
DO - 10.1093/molehr/gah125
M3 - Article
C2 - 15516358
AN - SCOPUS:14744305131
VL - 11
SP - 1
EP - 9
JO - Molecular Human Reproduction
JF - Molecular Human Reproduction
SN - 1360-9947
IS - 1
ER -