Alterations In Viscoelastic Properties Of Isolated Neurepithelium From Normal And Neural Tube Defects Mouse Embryo

Objective Neurulation is driven by both changes in neurepithelial cell shape and other form-shaping events. The purpose of this study is to characterize the mechanical behavior of and to determine the biomechanical properties of neurepithelium isolated from Normal and Neural Tube Defects embryo.Methods Adult Kunming female mouse were used in this study. They were randomly assigned into two groups. Neural tube defects (NTDs) mouse model was induced by retinoic acid medication at embryo 7.25d in experiment group. The control group received same volume edible balm. Then mouse were killed by vertebra dislocation and the embryos were harvested at embryo 9.5d and 11.5d respectively. The neural tube were isolated from embryo with dissection needle and made into neurepithelial cells suspension. The micropipette aspiration combined with a standard linear viscoelastic half-space model was used to characterize viscoelastic behavior of normal and NTDs neurepithelium.Results About 48% mouse had obvious neural tube defects in the experiment group. The mean diameter of neurepithelium from control and experiment groups were not significantly different (P>0.05). In response to a step pressure, neurepithelium exhibited viscoelastic solid creep behavior characterized initially by a jump in displacement followed by a monotonically decreasing rate of deformation that generally reached an equilibrium displacement within 90s. No differences were found in the viscoelastic parameters of neurepithelium between E9.5d and E11.5d in control groups (P>0.05). While compared with control group, the viscoelastic parameters of neurepithelium either E9.5d or 11.5d increased significantly in experiment group(P<0.05).Conclusion Neural tube defects mouse model was successfully induced by retinoic acid medication. The experimental data showed that the mechanical behavior of neurepithelial cells is that of a viscoelastic solid. There was no change of stiffness or neurepithelium passive deformability between E9.5d and 11.5d control group. However, neurepithelium in NTDs group showed stiffer, and had higher tension to resist external force and slower passive deformability. It suggested that alteration of cellular deformability might lead to NTDs, and the mechanism of NTDs was testified from biomechanical viewpoint.