Related Experiment Videos
Altering intracellular pH disrupts development and cellular organization in preimplantation hamster embryos
J M Squirrell1, M Lane, B D Bavister
1Department of Animal Health and Biomedical Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA. jsquirre@facstaff.wics.edu
Insights
Altering intracellular pH (pHi) in hamster embryos disrupts mitochondrial and microfilament organization, impairing embryo development. Recovery occurred upon compound removal, linking ionic balance to developmental competence.
Area of Science:
- Embryology
- Cell Biology
- Developmental Biology
Background:
- Intracellular pH (pHi) regulation is crucial for early embryo development.
- Mitochondrial organization disruption correlates with reduced developmental competence in vitro.
Purpose of the Study:
- To investigate the relationship between pHi and cytoplasmic organization in hamster embryos.
- To determine the effects of altered pHi on embryo development, mitochondrial distribution, and cytoskeletal organization.
Main Methods:
- Hamster embryos were treated with weak base (trimethylamine) to increase pHi and weak acid (5,5-dimethyl-2,4-oxazolinedione) to decrease pHi.
- Mitochondrial distribution, cytoskeletal organization (microfilaments and microtubules), and embryo development were assessed.
- Two-photon imaging was used to observe temporal changes in mitochondrial distribution in living embryos.
Main Results:
- Both increasing and decreasing pHi reduced embryo development and disrupted perinuclear mitochondrial organization.
- Microfilament organization was perturbed by both treatments, while microtubule cytoskeleton remained unaffected.
- Mitochondrial disruption progressed faster in alkalinized embryos compared to acidified embryos.
- Observed disruptions were not due to acute toxicity as embryos recovered developmentally after compound removal.
Conclusions:
- Altering pHi disrupts cytoplasmic organization, specifically mitochondrial and microfilament networks, in early cleavage stage hamster embryos.
- Ionic homeostasis is intrinsically linked to structural integrity and developmental competence in preimplantation embryos.
- These findings highlight the critical role of pHi regulation in maintaining cellular organization necessary for successful embryonic development.
Abstract:
In early cleavage stage hamster embryos, the inability to regulate intracellular pH (pHi) properly is associated with reduced developmental competence in vitro. The disruption of mitochondrial organization is also correlated with reduced development in vitro. To determine the relationship between pHi and the disruption of cytoplasmic organization, we examined the effects of altering pHi on hamster embryo development, mitochondrial distribution, and cytoskeletal organization. The weak base trimethylamine was used to increase pHi and was found to reduce embryo development and disrupt the perinuclear organization of mitochondria. The weak acid 5,5-dimethyl-2,4-oxazolinedione was used to decrease pH(i) and was also found to reduce development and disrupt the perinuclear organization of mitochondria. With either treatment, the microfilament organization was perturbed, but the microtubule cytoskeleton was not. However, the temporal progression of the disruption of mitochondrial distribution was more rapid in alkalinized embryos than acidified embryos, as revealed by two-photon imaging of living embryos. Additionally, the disruption of the microfilament network by the two treatments was not identical. The cytoplasmic disruptions observed were not due to acute toxicity of the compounds because embryos recovered developmentally when the treatment compounds were removed. These observations link ionic homeostasis, structural integrity and developmental competence in preimplantation hamster embryos.