Starr 2022 Curr Res Physiol

Starr VJ, Dzialowski EM (2022) Developing chicken cardiac muscle mitochondria are resistant to variations in incubation oxygen levels. https://doi.org/10.1016/j.crphys.2022.03.001

» Curr Res Physiol 5:151-57. PMID: 35345510 Open Access

Starr Vanessa J,  Dzialowski Edward M (2022) Curr Res Physiol

Abstract: Chronic exposure to hypoxia during vertebrate development can produce abnormal cardiovascular morphology and function. The aim of this study was to examine cardiac mitochondria function in an avian model, the chicken, in response to embryonic development under hypoxic (15% O₂), normoxic (21% O₂), or hyperoxic (40% O₂) incubation conditions.

Chicken embryos were incubated in hypoxia, normoxia, or hyperoxia beginning on day 5 of incubation through hatching. Cardiac mitochondria oxygen flux and reactive oxygen species production were measured in permeabilized cardiac fibers from externally pipped and 1-day post hatchlings.

Altering oxygen during development had a large effect on body and heart masses of externally pipped embryos and 1-day old hatchlings. Hypoxic animals had smaller body masses and absolute heart masses, but proportionally similar sized hearts compared to normoxic animals during external pipping. Hyperoxic animals were larger with larger hearts than normoxic animals during external pipping. Mitochondrial oxygen flux in permeabilized cardiac muscle fibers revealed limited effects of developing under altered oxygen conditions, with only oxygen flux through cytochrome oxidase being lower in hypoxic hearts compared with hyperoxic hearts. Oxygen flux in leak and oxidative phosphorylation states were not affected by developmental oxygen levels. Mitochondrial reactive oxygen species production under leak and oxidative phosphorylation states studied did not differ between any developmental oxygen treatment.

These results suggest that cardiac mitochondria function of the developing chicken is not altered by developing in ovo under different oxygen levels. • Keywords: AA, Antimycin A, ADP, Adenosine diphosphate, COX, Cytochrome oxidase, Cardiac mitochondria, Chicken, EP, External pipping, GMP, Glutamate, Malate, Pyruvate, Hyperoxia, Hypoxia, IP, Internal pipping, LEAK, Mitochondrial leak respiration, OMY, Oligomycin, OXPHOS, Mitochondrial oxidative phosphorylation, ROS, Reactive oxygen species, ROT, Rotenone, Reactive oxygen species, S, Succinate, TMPD, N, N, N’, N’-tetramethyl-p-phenylenediamine, dph, Days post hatching • Bioblast editor: Plangger M • O2k-Network Lab: US TX Denton Dzialowski EM

Labels: MiParea: Respiration, Developmental biology 

Stress:Hypoxia  Organism: Chicken  Tissue;cell: Heart  Preparation: Permeabilized tissue 

Coupling state: LEAK, OXPHOS  Pathway: N, S, CIV, NS, ROX  HRR: Oxygraph-2k, O2k-Fluorometer 

2022-11, AmR