Regional hypoxia elicits regional changes in chorioallantoic membrane vascular density in alligator but not chicken embryos

Corona, Teresa B; Warburton, Stephen J.

doi:10.1016/s1095-6433(99)00159-2

Cited by 47 publications

(41 citation statements)

References 12 publications

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“…CAM vessel density index protocols were created using previously published conventions (Strick et al 1991;Höper and Jahn 1995;Corona et al 1999). Images of each embryo were taken at #3.5 using a Javelin camera mounted on a Leica WILD M3Z microscope.…”

Section: Cam Vessel Density Index Measurementmentioning

confidence: 99%

Reduced Heart Rate and Cardiac Output Differentially Affect Angiogenesis, Growth, and Development in Early Chicken Embryos (Gallus domesticus)

Branum

Yamada-Fisher

Burggren

2013

Physiological and Biochemical Zoology

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An increase in both vascular circumferential tension and shear stress in the developing vasculature of the chicken embryo has been hypothesized to stimulate angiogenesis in the developing peripheral circulation chorioallantoic membrane (CAM). To test this hypothesis, angiogenesis in the CAM, development, and growth were measured in the early chicken embryo, following acute and chronic topical application of the purely bradycardic drug ZD7288. At hour 56, ZD7288 reduced heart rate (f H ) by ∼30% but had no significant effect on stroke volume (∼ mL), collectively resulting in a significant fall in 0.19 ‫ע‬ 0.2 cardiac output (CO) from ∼ to mL min Ϫ1 . Mean 27 ‫ע‬ 3 ‫ע81‬ 2 f H at 72 h of development was similarly significantly lowered by acute ZD7288 treatment (250 mM) to beats min Ϫ1 , 128 ‫ע‬ 0.3 compared with and beats min Ϫ1 in con-174.5 ‫ע‬ 0.3 174.7 ‫ע‬ 0.8 trol and Pannett-Compton (P-C) saline-treated embryos, respectively. Chronic dosing with ZD7288-and the attendant decreases in f H and CO-did not change eye diameter or cervical flexion (key indicators of development rate) at 120 h but significantly reduced overall growth (wet and dry body mass decreased by 20%). CAM vessel density index (reflecting angiogenesis) measured 200-400 mm from the umbilical stalk was not altered, but ZD7288 reduced vessel numbers-and therefore vessel density-by 13%-16% more distally (500-600 mm from umbilical stalk) in the CAM. In the ZD7288-treated embryos, a decrease in vessel length was found within the second branch order (∼300-400 mm from the umbilical stock), while a decrease in vessel diameter was found closer to the umbilical stock, beginning in the first branch order (∼200-300 mm). Paradoxically, chronic application of P-C saline also reduced peripheral CAM vessel density index at 500 and 600 mm by 13% and 7%, respectively, likely from washout of local angiogenic factors. In summary, decreased f H with reduced CO did not slow development rate but reduced embryonic growth rate and angiogenesis in the CAM periphery. This study demonstrates for the first time that different processes in the ontogeny of the early vertebrate embryo (i.e., hypertrophic growth vs. development) have differential sensitivities to altered convective blood flow.

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Section: Cam Vessel Density Index Measurementmentioning

confidence: 99%

Reduced Heart Rate and Cardiac Output Differentially Affect Angiogenesis, Growth, and Development in Early Chicken Embryos (Gallus domesticus)

Branum

Yamada-Fisher

Burggren

2013

Physiological and Biochemical Zoology

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“…Access to O 2 from inside the nest chamber depends on maternal nest-site selection, climate events such as excess rainfall and flooding, and the metabolism of microbes and sibling eggs that may modify the composition of gases within the nest chamber (Seymour et al 1986;Joanen & McNease 1989;Booth 1998;Ackerman & Lott 2004). In addition, external regional hypoxia may occur within an egg when eggs are partially immersed in liquid water (Booth 1998;Corona & Warburton 2000). In response to external regional hypoxia, reptile embryos are able to shunt blood away from non-exchanging areas (via hypoxic vasoconstriction), increase cardiac output and blood O 2 -carrying capacity by polycythemia (increase in erythrocyte numbers), and allosterically modify hemoglobin (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…In response to external regional hypoxia, reptile embryos are able to shunt blood away from non-exchanging areas (via hypoxic vasoconstriction), increase cardiac output and blood O 2 -carrying capacity by polycythemia (increase in erythrocyte numbers), and allosterically modify hemoglobin (e.g. Corona & Warburton 2000;Cordero et al 2017). Nevertheless, some fundamental questions remain unanswered with respect to external regional hypoxia.…”

Section: Introductionmentioning

confidence: 99%

“…To test these 2 hypotheses, we experimentally generated external regional hypoxia by sealing either the upper half or bottom half of the egg surface of snakes and turtles, thus rendering it impermeable to O 2 and preventing water exchange (Corona & Warburton 2000;Du et al 2010b). We then monitored the water exchange of eggs, the growth pattern of the opaque white patch in turtle eggs, the embryonic heart rate, the developmental rate and hatchling traits (morphology and locomotor performance) to understand how embryos respond to external regional hypoxia.…”

Section: Introductionmentioning

confidence: 99%

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Reduced egg shell permeability affects embryonic development and hatchling traits in Lycodon rufozonatum and Pelodiscus sinensis

Tang

Chen

2018

Integrative Zoology

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The response of embryos to unpredictable hypoxia is critical for successful embryonic development, yet there remain significant gaps in our understanding of such responses in reptiles with different types of egg shell. We experimentally generated external regional hypoxia by sealing either the upper half or bottom half of the surface area of eggs in 2 species of reptiles (snake [Lycodon rufozonatum] with parchment egg shell and Chinese softshelled turtle [Pelodiscus sinensis] with rigid egg shell), then monitored the growth pattern of the opaque white patch in turtle eggs (a membrane that attaches the embryo to the egg shell and plays an important role in gas exchange), the embryonic heart rate, the developmental rate and the hatchling traits in turtle and snake eggs in response to external regional hypoxia. The snake embryos from the hypoxia treatments facultatively increased their heart rate during incubation, and turtle embryos from the upper-half hypoxia treatment enhanced their growth of the opaque white patch. Furthermore, the incubation period and hatching success of embryos were not affected by the hypoxia treatment in these 2 species. External regional hypoxia significantly affected embryonic yolk utilization and offspring size in the snake and turtle. Compared to sham controls, embryos from the upper-half hypoxia treatment used less energy from yolk and, therefore, developed into smaller hatchlings, but embryos from the bottom-half hypoxia treatment did not.

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“…Strick et al (1991), who incubated chicken eggs in 12, 16, 21, 45 or 70% O 2 from day 7 to 14, showed that the graded exposure to O 2 produced a dose-related change in the VDI: hypoxia increased and hyperoxia decreased VDI. Corona and Warburton (2000) covered ~25% of chicken eggshells with beeswax before placing them in an incubator and measured VDI in the formed hypoxic region of the CAM on day 12 of incubation. They did not find VDI differences between the hypoxic and the control regions at this early stage.…”

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confidence: 99%

Regional and developmental variations of blood vessel morphometry in the chick embryo chorioallantoic membrane

Reizis

Hammel

2005

Journal of Experimental Biology

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Avian eggs contain all the necessary materials for embryonic development except for oxygen, which diffuses in from the environment via pores in the hard, calcified eggshell to the chorioallantoic membrane (CAM), the respiratory organ, which is rich in blood vessels. An air cell is formed at the blunt pole of the egg between the two membranes of the eggshell and enlarges during incubation due to water vapor loss. In this study of the CAM of chicken eggs, we compared blood vessel numerical density Since the eggshell over the air cell has a relatively greater porosity, and the respiratory gas exchange ratio there is higher than at other areas of the egg, there is a correlation between all the above morphometric data and the eggshell porosity. This suggests optimization of embryonic gas exchange in the chicken egg. We would like to propose that, during natural incubation, an increased gas diffusion under the air cell, together with increased blood vessel numerical density, may compensate for covering of the central part of the eggshell by the incubating parent.

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Regional hypoxia elicits regional changes in chorioallantoic membrane vascular density in alligator but not chicken embryos

Cited by 47 publications

References 12 publications

Reduced Heart Rate and Cardiac Output Differentially Affect Angiogenesis, Growth, and Development in Early Chicken Embryos (Gallus domesticus)

Reduced Heart Rate and Cardiac Output Differentially Affect Angiogenesis, Growth, and Development in Early Chicken Embryos (Gallus domesticus)

Reduced egg shell permeability affects embryonic development and hatchling traits in Lycodon rufozonatum and Pelodiscus sinensis

Regional and developmental variations of blood vessel morphometry in the chick embryo chorioallantoic membrane

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