In ovo imaging using ostrich eggs – biomagnetism for detection of vitality and embryonal movement during isoflurane anesthesia

Ziel/Aim In ovo imaging using ostrich eggs has been described as a potential alternative to common animal testing using rats or mice. The main advantage of this approach is its independence from small animal imaging devices as ostrich eggs provide good image quality on regular CT, MRI or PET used in clinical routine in examinations of humans. However, movement of embryos during imaging studies (e.g. listmode PET) produce artifacts. The aims of this study were 1) to explore the feasibility of biomagnetism to detect heart actions and embryonal movement and to use these findings 2) to investigate the effect of isoflurane anesthesia on ostrich embyros.

Methodik/Methods A standard magnetencephalograp (MEG, Neuromag, Elekta, Sweden) used for brain studies was used to detect embryonal signals from ostrich eggs on developmental day 34. A metal-free case with remote control of air/isoflurane in- and outflow was designed to hold the ostrich egg within the MEG system. Signals were instantly shown on a screen and data were also post-processed. For assessing effects of anesthesia, 8 ostrich eggs were investigated using isoflurane 6 % which was directed into the designed case for 90 minutes. Biomagnetic signals were recorded simultaneously. A control group consisting of 8 different ostrich eggs was also investigated.

Ergebnisse/Results Correct placement of the embryo close to detector produced clear cardiac signals similar to ECG in all eggs. Postprocessing revealed frequent movement of embryos without anesthesia. The exposure to isoflurane 6 % led to significant decrease of movement signals in 100 % (8/8) ostrich embryos after 2 minutes. Movement was significantly lower in the isoflurane group vs. control group. There were no isoflurane-related deaths.

Schlussfolgerungen/Conclusions This study shows that biomagnetism is feasible to detect heart actions and movement of ostrich embryos. Also, anesthesia using isoflurane is safe and leads to rapid decrease of embryonal movement, which is an important prerequisite for the implementation of in ovo imaging using ostrich eggs in preclinical imaging studies.

Publication History

Article published online:
08 April 2021