Biostabilization Laboratory - Lower Saxony Centre for Biomedical Engineering, Implant Research and Development, NIFE, Stadtfelddamm 34, 30625, Hannover, Germany.
Unit for Reproductive Medicine - Clinic for Horses, University of Veterinary Medicine Hannover, Hannover, Germany.
Sci Rep. 2021 Oct 6;11(1):19812. doi: 10.1038/s41598-021-99287-9.
Cryopreservation can be used to store equine oocytes for extended periods so that they can be used in artificial reproduction technologies at a desired time point. It requires use of cryoprotective agents (CPAs) to protect the oocytes against freezing injury. The intracellular introduction of CPAs, however, may cause irreversible osmotic damage. The response of cells exposed to CPA solutions is governed by the permeability of the cellular membrane towards water and the CPAs. In this study, a mathematical mass transport model describing the permeation of water and CPAs across an oocyte membrane was used to simulate oocyte volume responses and concomitant intracellular CPA concentrations during the exposure of oocytes to CPA solutions. The results of the analytical simulations were subsequently used to develop a phenomenological finite element method (FEM) continuum model to capture the response of oocytes exposed to CPA solutions with spatial information. FEM simulations were used to depict spatial differences in CPA concentration during CPA permeation, namely at locations near the membrane surface and towards the middle of the cell, and to capture corresponding changes in deformation and hydrostatic pressure. FEM simulations of the multiple processes occurring during CPA loading of oocytes are a valuable tool to increase our understanding of the mechanisms underlying cryopreservation outcome.
冷冻保存可用于长时间储存马的卵母细胞，以便在需要的时候可以在人工繁殖技术中使用。这需要使用冷冻保护剂（CPAs）来保护卵母细胞免受冷冻损伤。然而，CPAs 的细胞内引入可能会导致不可逆转的渗透损伤。暴露于 CPA 溶液中的细胞的反应受细胞膜对水和 CPAs 的渗透性的控制。在这项研究中，使用了一个描述水和 CPAs 穿过卵母细胞膜渗透的数学质量传输模型，以模拟卵母细胞在暴露于 CPA 溶液时的体积响应和伴随的细胞内 CPA 浓度。随后，使用分析模拟的结果开发了一种现象有限元方法（FEM）连续体模型，以获取具有空间信息的卵母细胞暴露于 CPA 溶液的响应。FEM 模拟用于描绘 CPA 渗透过程中 CPA 浓度的空间差异，即在靠近细胞膜表面的位置和细胞中间的位置，并捕获相应的变形和静压变化。FEM 模拟卵母细胞 CPA 加载过程中发生的多个过程是增加我们对冷冻保存结果背后机制的理解的有价值的工具。
