Embryo exposure to elevated cortisol level leads to cardiac performance dysfunction in zebrafish
Dinushan Nesan1, Mathilakath M Vijayan
1Department of Biology, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1.
Molecular and Cellular Endocrinology
|July 31, 2012
Summary
Elevated cortisol in zebrafish embryos caused heart deformities and reduced cardiac function, impacting survival. This highlights risks of maternal stress on offspring development.
Area of Science:
- Developmental biology
- Cardiovascular physiology
- Endocrinology
Background:
- Zebrafish embryos lack de novo cortisol synthesis until after hatching.
- Maternal stress can lead to abnormal cortisol deposition in embryos.
- Cortisol's role in pre-hatch development is not fully understood.
Purpose of the Study:
- To investigate the impact of elevated embryonic cortisol on zebrafish cardiac performance.
- To identify molecular mechanisms linking cortisol exposure to cardiac dysfunction.
Main Methods:
- Microinjection of cortisol into one-cell zebrafish embryos.
- Assessment of heart morphology and function (heartbeat rate) post-hatch.
- Quantitative analysis of key cardiac gene expression.
Main Results:
- Elevated cortisol caused increased heart deformities (pericardial edema, malformed chambers).
- Resting heartbeat and response to stress were significantly reduced in exposed zebrafish.
- Expression of critical cardiac genes (nkx2.5, MLC1, TnT2A, Ca-ATPase) was suppressed.
Conclusions:
- High cortisol levels during zebrafish embryogenesis impair cardiac development and function.
- This impairment is mechanistically linked to the downregulation of essential cardiac genes.
- Embryonic cortisol exposure, mimicking maternal stress, may reduce offspring survival.
