Time-lapse mechanical imaging of neural tube closure in live embryo using Brillouin microscopy

Abstract

Neural tube closure (NTC) is a complex process of embryonic development involving molecular, cellular, and biomechanical mechanisms. While the genetic factors and biochemical signaling have been extensively investigated, the role of tissue biomechanics remains mostly unexplored due to the lack of tools. Here, we developed an optical modality that can conduct time-lapse mechanical imaging of neural plate tissue as the embryo is experiencing neurulation. This technique is based on the combination of a confocal Brillouin microscope and a modified ex ovo culturing of chick embryo with an on-stage incubator. With this technique, for the first time, we captured the mechanical evolution of the neural plate tissue with live embryos. Specifically, we observed the continuous increase in tissue modulus of the neural plate during NTC for ex ovo cultured embryos, which is consistent with the data of in ovo culture as well as previous studies. Beyond that, we found that the increase in tissue modulus was highly correlated with the tissue thickening and bending. We foresee this non-contact and label-free technique opening new opportunities to understand the biomechanical mechanisms in embryonic development.

Imaging Approaches and the Quantitative Analysis of Heart Development

“…New approaches now allow us to measure the mechanical properties of developing embryos. Brillouin microscopy has been used to image mechanical properties during neural tube closure in live chicken embryos without disrupting its development [98]. This is a promising technique to study the mechanical forces involved in heart development [11].…”

Prickle2 regulates apical junction remodeling and tissue fluidity during vertebrate neurulation

“…10K). These cues may include tensile stresses originating from the AP elongation of embryo body axis (Christodoulou and Skourides, 2022; Clausi and Brodland, 1993; Davidson and Keller, 1999; Handler et al, 2023; Hirano et al, 2022; Moon and Xiong, 2022; Smith and Schoenwolf, 1997; Sokol, 2016; Xiong et al, 2020; Zhou et al, 2015). Alternatively, diffusible morphogen gradients may be responsible the directionality of Pk2 effects.…”

Push and pull: how to measure the forces that sculpt embryos

“…"We've applied this optical method to chick embryos to monitor how the stiffness changes when the neural tube is closing," says Zhang. Brillouin allowed his team to document this process over more than 21 hours, measuring a steady increase in tissue stiffness as the neural-tube tissue thickens, bends and closes 8 . Chan has also found Brillouin microscopy to be a valuable tool.…”