The chick embryo is used in our lab as a good experimental model to study human embryonic development. Our project involves the study of the role of two extraembryonic membranes - the amnion and vitelline membrane - on rotation during early development (48-56 hours out of a 21 day incubation period) in the chick. Embryonic rotation begins at the cranial end of the embryo and continues caudally until the embryo is completely turned on its side. This rotation is necessary for the proper development of major organs such as the heart and the brain. Prior research shows that rotation of the embryo is needed for normal s-looping, the transformation of the heart tube into the correct orientation to form atrium and ventricles, and that hindering this rotation leads to abnormal cardiac looping and some morphological anomalies (Ramasubramanian et.al 2018). Another study claims that torsion is important for organs to develop on the correct side of the body (Chen et.al 2017). In our experiments, chick embryos are harvested and scanned along their transverse, sagittal, and coronal planes, with an OCT imaging system. These images are then examined to determine where and how much the embryo rotated transversely. Embryos where torsion has not yet been initiated are manipulated with a small needle. In one experiment the needle is used to push the head out and on top of the amnion. The needle is used in the other experiment to carefully remove the vitelline membrane from covering the embryo. All of the embryos are then placed in a ziploc bag with oxygen, and incubated. Images are taken again at 5 hours and 10 hours to observe how perturbations affected development. Preliminary results show that rotation can still occur without the forces applied by the vitelline or the amniotic membranes.
Chen, Z, Guo, Q, Dai, E, Forsch, N, & Taber, L A. 2017. How the Embryonic Brain Twists. J. R. Soc.Interface,13.
Ramasubramanian, A, Capaldi, X, Bradner, S A, & Gangi, L. 2018. On the Biomechanics of Cardiac S-looping:insights from modeling and perturbation studies. Manuscript in review.