Strong static magnetic field delayed the early development of zebrafish

Abstract

One of the major topics in magnetobiology is the biological effects of strong static magnetic field (SMF) on living organisms. However, there has been a paucity of the comprehensive study of the long-term effects of strong SMF on an animal's development. Here, we explored this question with zebrafish, an excellent model organism for developmental study. In our research, zebrafish eggs, just after fertilization, were exposed to a 9.0 T SMF for 24 h, the critical period of post-fertilization development from cleavage to segmentation. The effects of strong SMF exposure on the following developmental progress of zebrafish were studied until 6 days post-fertilization (dpf). Results showed that 9.0 T SMF exposure did not influence the survival or the general developmental scenario of zebrafish embryos. However, it slowed down the developmental pace of the whole animal, and the late developers would catch up with their control peers after the SMF was removed. We proposed a mechanical model and deduced that the development delaying effect was caused by the interference of SMF in microtubule and spindle positioning during mitosis, especially in early cleavages. Our research data provide insights into how strong SMF influences the developing organisms through basic physical interactions with intracellular macromolecules.

Effects of Moderate to High Static Magnetic Fields on Reproduction

“…For example, Sun et al [2019] found that there were no abnormalities in the embryos of zebrafish when they were exposed to 100 mT inhomogeneous SMF by permanent magnet for 15 days, but their swimming behavior was affected. Moreover, Ge et al [2019] showed that the treatment of 9 T homogeneous SMF for 24 h slowed down the developmental pace of zebrafish embryos, and the late embryos would catch up with their control peers after the SMF was removed.…”

“…For example, Denegre et al [1998] analyzed the length of the astral microtubules, the diamagnetic anisotropy, and the bending stiffness of the microtubules and concluded that the effects of SMF on the cleavage plane should be caused by the SMF action on microtubules. Ge et al [2019] also proposed a mechanical model and deduced that the delaying effect of SMF on zebrafish embryo development was caused by the interference of SMF in microtubule and spindle positioning during mitosis.…”

Automated staging of zebrafish embryos using machine learning

“…Such delays are difficult to quantify without manually staging large numbers of embryos, which is inconvenient, subjective and time-consuming, especially when assessing developmental abnormalities ( Jeanray et al, 2015 ; Teixidó et al, 2019 ). Adding to this difficulty, the delay is often temporary, and transgenic or treated embryos ‘catch up’ with their WT counterparts ( Elabd et al, 2019 ; Ge et al, 2019 ; Kamei et al, 2018 ). It is therefore important to identify exactly when the delay is occurring to account for it in the study.…”

Automated staging of zebrafish embryos using machine learning

“…Such delays are difficult to quantify without manually staging large numbers of embryos, which is inconvenient, subjective and time-consuming, especially when assessing developmental abnormalities (Jeanray et al, 2015;Teixidó et al, 2019). Adding to this difficulty, the delay is often temporary, and transgenic or treated embryos 'catch up' with their WT counterparts (Elabd et al, 2019;Ge et al, 2019;Kamei et al, 2018). It is therefore important to identify exactly when the delay is occurring to account for it in the study.…”