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Published on: June 6, 2016
Intracellular pH regulation in human preimplantation embryos
K P Phillips1, M C Léveillé, P Claman
1Loeb Research Institute, Ottawa Hospital and Department Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.
Human Reproduction (Oxford, England)
|March 31, 2000
Summary
Intracellular pH (pH(i)) in early human embryos is maintained by at least two key transporters: the bicarbonate/chloride exchanger and the sodium/hydrogen antiporter. These systems ensure stable pH for crucial early development.
Area of Science:
- Embryology
- Cell Physiology
- Reproductive Biology
Background:
- Intracellular pH (pH(i)) is critical for early human embryo development.
- Understanding pH regulatory mechanisms is essential for improving IVF outcomes and embryo viability.
Purpose of the Study:
- To investigate the specific transporters responsible for regulating intracellular pH in human cleavage-stage embryos.
- To determine the set-points and dependencies of these pH regulatory mechanisms.
Main Methods:
- Measurement of intracellular pH (pH(i)) in 2-8 cell human embryos.
- Assessing recovery from induced alkalosis and acidosis using specific ion manipulations (Cl(-) removal, Na(+) dependence).
- Utilizing pharmacological inhibitors like 4,4'-diisocyanatostilbene-2,2'-disulphonic acid and amiloride.
Main Results:
- Human cleavage-stage embryos (pH(i) 7.12 ± 0.008) utilize a Cl(-)-dependent bicarbonate/chloride exchanger to counteract alkalosis (set-point 7.2-7.3).
- Sodium-dependent Na(+)/H(+) antiporter activity regulates recovery from acidosis up to pH(i) 6.8 (amiloride-sensitive, HCO(3)(-)-independent).
- A second Na(+)- and HCO(3)(-)-dependent system contributes to acidosis recovery up to pH(i) 7.1.
Conclusions:
- Early human embryos employ multiple, opposing transport systems to maintain a narrow intracellular pH range.
- The bicarbonate/chloride exchanger and sodium/hydrogen antiporter are key regulators of pH homeostasis in cleavage-stage embryos.
- These findings provide insights into the physiological resilience of human preimplantation embryos.
