Strong static magnetic field delayed the early development of zebrafish.

Shuchao Ge,Dengfeng Huang,Yuan Cai,Hongyuan Jiang,Bing Hu,Jingchen Li,Jun Fang

doi:10.1098/rsob.190137

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.

Highlights

In modern societies, compared with geomagnetic field (GMF), people have access to much stronger static magnetic fields (SMFs), like the one used in magnetic resonance imaging (MRI) and those manufactured in several national high magnetic field laboratories
The eggs of wild-type zebrafish line AB were exposed to 9.0 T SMF from fertilization to 4, 8 or 24 hpf
Since the performance of optokinetic response (OKR) depends on the maturation extent of the retina [22,23], these results indicated that strong SMF delayed the development of retina

Summary

Introduction

In modern societies, compared with geomagnetic field (GMF), people have access to much stronger static magnetic fields (SMFs), like the one used in magnetic resonance imaging (MRI) and those manufactured in several national high magnetic field laboratories. While some reported that strong SMF did not exert severe effects on the development of Xenopus laevis (6.34 T for 6 and 18 h or 8 T for 20 h) [2,3,4] or mice (1.5 and 7 T, 75 min each day during the entire pregnancy, or 4.7 T exposure from 7.5 to 9.5 day of gestation) [5,6], others observed obvious side effects, including the altered cleavage plane (1.7–16.7 T exposure from fertilization to the third cleavage) [7,8] or cortical pigmentation (9.4 T exposure from 15 to 109 min) [9] in Xenopus eggs, retarded development and aberrant gene expression in Xenopus embryos (15 T exposure from uncleaved to 2-cell, 2-cell to blastula and blastula to neurula) [10], shortened lifespan in Caenorhabditis elegans (8 T for 1, 3 and 5 h) [11], delayed hatching in mosquito eggs

Methods

Discussion

Conclusion