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An ex-ovo Chicken Embryo Culture System Suitable for Imaging and Microsurgery Applications
Published on: October 24, 2010
Hypoxic incubation creates differential morphological effects during specific developmental critical windows in the
1Department of Biological Sciences, University of North Texas, P.O. Box 305189, Denton, TX 76203-5189, USA. t-chan@northwestern.edu
Insights
Hypoxia during chick development impacts eye and beak growth, but not major organs. The chorioallantoic membrane compensates for low oxygen by increasing its mass.
Area of Science:
- Developmental biology
- Physiology
Background:
- Hypoxia, or low oxygen, is known to inhibit vertebrate development.
- The specific timing and organ-specific effects of hypoxia during embryonic development are not well understood.
Purpose of the Study:
- To investigate the effects of continuous hypoxic exposure at different developmental stages on chick embryos.
- To determine the organ-specific responses and potential for recovery from hypoxia.
Main Methods:
- Chick embryos were exposed to hypoxia (15% O2) during specific developmental windows (Days 1-6, 6-12, 12-18, or Days 1-18).
- Morphometric measurements of major organ systems were taken after hypoxic exposure.
Main Results:
- Early hypoxia reduced eye mass and beak length.
- Liver, brain, heart, kidneys, stomach, intestines, and long bones were unaffected by hypoxia.
- Chorioallantoic membrane mass significantly increased in late and continuously hypoxic embryos.
Conclusions:
- Hypoxic exposure during critical developmental windows causes differential organ development effects.
- The chorioallantoic membrane's adaptive increase in mass may mitigate some negative impacts of hypoxia.
- Some effects, like reduced eye mass and beak length, can be repaired with extended incubation.
Abstract:
Hypoxia inhibits vertebrate development, but the magnitude and timing of organ-specific effects are poorly understood. Chick embryos were exposed continuously to hypoxia (15% O2) throughout Days 1-6, 6-12, 12-18 or Days 1-18 of development, followed by morphometric measurements of major organ systems. Early hypoxic exposure reduced eye mass and beak length when measured in middle development. Liver, brain, heart, kidneys, stomach, intestines and skeletal long bones were not affected by hypoxia at any developmental stage. The chorioallantoic membrane (CAM) mass was unchanged by hypoxic exposure in early or mid-development, but CAM mass on Day 18 increased strikingly (40 and 60% in late and continuous populations, respectively) in response to hypoxic exposure. The increase in CAM mass presumably enhances oxygen delivery, thus minimizing the detrimental effects of hypoxia on development and growth. Hypoxic exposure at key critical windows in development thus results in differential effects on organ development, some of which can subsequently be repaired through additional incubation (yolk mass, eye mass, beak length).
