The Effect of Insulin Administration in ovo on Liver Glucose 6-Phosphatase in Chick Embryos

Background. Although chick embryogenesis has been studied extensively, there has been growing interest in the investigation of skeletogenesis. In addition to improved poultry health and minimized economic loss, a greater understanding of skeletal abnormalities can also have implications for human medicine. Truein vivostudies require noninvasive imaging techniques such as high-resolution microCT. However, the manual analysis of acquired images is both time consuming and subjective.Methods. We have developed a system for automated image segmentation that entails object-based image analysis followed by the classification of the extracted image objects. For image segmentation, a rule set was developed using Definiens image analysis software. The classification engine was implemented using the WEKA machine learning tool.Results. Our system reduces analysis time and observer bias while maintaining high accuracy. Applying the system to the quantification of long bone growth has allowed us to present the first truein ovodata for bone length growth recorded in the same chick embryos.Conclusions. The procedures developed represent an innovative approach for the automated segmentation, classification, quantification, and visualization of microCT images. MicroCT offers the possibility of performing longitudinal studies and thereby provides unique insights into the morpho- and embryogenesis of live chick embryos.

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Optogenetic regulation of leg movement in midstage chick embryos through peripheral nerve stimulation

Journal of Neurophysiology ◽

10.1152/jn.00712.2011 ◽

2011 ◽

Vol 106 (5) ◽

pp. 2776-2782 ◽

Cited By ~ 11

Author(s):

Andrew A. Sharp ◽

Sylvia Fromherz

Keyword(s):

Nervous System ◽

Neuronal Activity ◽

Expression System ◽

Continuous Illumination ◽

Chick Embryos ◽

Motor Axons ◽

In Ovo ◽

Full Extension ◽

Sensorimotor Development ◽

Spontaneous Movements

Numerous disorders that affect proper development, including the structure and function of the nervous system, are associated with altered embryonic movement. Ongoing challenges are to understand in detail how embryonic movement is generated and to understand better the connection between proper movement and normal nervous system function. Controlled manipulation of embryonic limb movement and neuronal activity to assess short- and long-term outcomes can be difficult. Optogenetics is a powerful new approach to modulate neuronal activity in vivo. In this study, we have used an optogenetics approach to activate peripheral motor axons and thus alter leg motility in the embryonic chick. We used electroporation of a transposon-based expression system to produce ChIEF, a channelrhodopsin-2 variant, in the lumbosacral spinal cord of chick embryos. The transposon-based system allows for stable incorporation of transgenes into the genomic DNA of recipient cells. ChIEF protein is detectable within 24 h of electroporation, largely membrane-localized, and found throughout embryonic development in both central and peripheral processes. The optical clarity of thin embryonic tissue allows detailed innervation patterns of ChIEF-containing motor axons to be visualized in the living embryo in ovo, and pulses of blue light delivered to the thigh can elicit stereotyped flexures of the leg when the embryo is at rest. Continuous illumination can disrupt full extension of the leg during spontaneous movements. Therefore, our results establish an optogenetics approach to alter normal peripheral axon function and to probe the role of movement and neuronal activity in sensorimotor development throughout embryogenesis.

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Oxygen consumption by chick embryos exposed to mechanical (shaking) stress

Journal of Applied Physiology ◽

10.1152/jappl.1979.46.2.298 ◽

1979 ◽

Vol 46 (2) ◽

pp. 298-301

Author(s):

R. R. Schmidt ◽

S. Kaplan ◽

J. J. Smith

Keyword(s):

Oxygen Consumption ◽

Developmental Stages ◽

Chick Embryos ◽

O2 Consumption ◽

In Ovo ◽

Consumption Values ◽

Induced Stress ◽

Early Return ◽

Functionally Impaired ◽

First Time

Stage 34 (8-day) and 41 (15-day) chick embryos (Gallus gallus; in ovo) were exposed (3 min) to two separate amounts of mechanical (shaking) stress. Oxygen consumption determinations, following a temperature equilibration period (60 min), were made on entire, intact eggs using a Warburg apparatus equipped with 130-ml flasks modified to hold the egg. Shaking at 300 excursions per minute (epm) resulted in depressed O2 consumption by stages 34 and 41. Only stage 34 embryos had markedly depressed O2 consumption values when shaken at 100 epm. When exposed to 300 epm and reincubated for either 1, 2, or 4 hr prior to O2 consumption determinations stage 34 embryos, following an early return to control levels exhibited a marked fall in O2 consumption by 4 h reincubation. The stage 41 embryos, on the other hand, demonstrated a gradual rise to control O2 consumption levels by 4 h reincubation. Oxygen consumption has now been shown for the first time in an embryonic system (at two distinct developmental stages) to be functionally impaired by mechanically induced stress.

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Heart rate changes mediate the embryotoxic effect of antiarrhythmic drugs in the chick embryo

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00679.2012 ◽

2013 ◽

Vol 304 (6) ◽

pp. H895-H902 ◽

Cited By ~ 15

Author(s):

Radka Kockova ◽

Jarmila Svatunkova ◽

Jiri Novotny ◽

Lucie Hejnova ◽

Bohuslav Ostadal ◽

...

Keyword(s):

Adverse Effect ◽

Heart Rate ◽

Cardiac Output ◽

Adrenergic Receptors ◽

Developmental Toxicity ◽

Premature Death ◽

Chick Embryos ◽

In Ovo ◽

Drug Induced ◽

Β Adrenergic Receptors

A significant increase in cardiovascular medication use during pregnancy occurred in recent years. Only limited evidence on safety profiles is available, and little is known about the mechanisms of adverse effect on the fetus. We hypothesized that drug-induced bradycardia is the leading mechanism of developmental toxicity. Embryotoxicity was tested in ovo after administration of various doses of metoprolol, carvedilol, or ivabradine. Embryonic day (ED) 4 and 8 chick embryos were studied by video microscopy and ultrasound biomicroscopy ex ovo after intraamniotic injection of the drug for a period of 30 min. Stroke volume was calculated by the Simpson method and prolate ellipsoid formula. Significant dose-dependent mortality was achieved in embryos injected with carvedilol and ivabradine. In ED4 embryos, metoprolol, carvedilol, and ivabradine reduced the heart rate by 33%, 27%, and 55%, respectively, compared with controls (6%). In ED8 embryos this effect was more pronounced with a heart rate reduction by 71%, 54%, and 53%, respectively (controls, 36%). Cardiac output decreased in all tested groups but only proved significant in the metoprolol group in ED8 embryos. The number of β-adrenergic receptors showed a downward tendency during embryonic development. A negative chronotropic effect of metoprolol, carvedilol, and ivabradine was increasingly pronounced with embryonic maturity despite a downward trend in the number of β-adrenergic receptors. This effect was associated with reduced cardiac output in chick embryos, probably leading to premature death. Although standard doses of these drugs appear relatively safe, high doses have a potentially adverse effect on the fetus through reduced heart rate.

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