Long-term exposure to a hypomagnetic field attenuates adult hippocampal neurogenesis and cognition

Bingfang Zhang,Lei Wang,Aisheng Zhan,Weixiang Guo,Lanxiang Tian,Min Wang,Yongxin Pan

doi:10.1038/s41467-021-21468-x

Abstract

Adult hippocampal neurogenesis contributes to learning and memory, and is sensitive to a variety of environmental stimuli. Exposure to a hypomagnetic field (HMF) influences the cognitive processes of various animals, from insects to human beings. However, whether HMF exposure affect adult hippocampal neurogenesis and hippocampus-dependent cognitions is still an enigma. Here, we showed that male C57BL/6 J mice exposed to HMF by means of near elimination of the geomagnetic field (GMF) exhibit significant impairments of adult hippocampal neurogenesis and hippocampus-dependent learning, which is strongly correlated with a reduction in the content of reactive oxygen species (ROS). However, these deficits seen in HMF-exposed mice could be rescued either by elevating ROS levels through pharmacological inhibition of ROS removal or by returning them back to GMF. Therefore, our results suggest that GMF plays an important role in adult hippocampal neurogenesis through maintaining appropriate endogenous ROS levels.

Highlights

Adult hippocampal neurogenesis contributes to learning and memory, and is sensitive to a variety of environmental stimuli
Compared to geomagnetic field (GMF)-exposed controls, we found that there is a significant reduction in the numbers of BrdU+GFAP+Sox2+ type 1 adult neural stem/progenitor cells (aNSCs) in hypomagnetic field (HMF)-exposed mice at 8-weeks HMF exposure (Fig. 1e, f), while such reduction effect on the numbers of BrdU+ GFAP-Sox2+ type 2 aNSCs began at as early as 2-weeks exposure to HMF (Fig. 1g, h), suggesting that HMF exposure primarily affects proliferating type 2 aNSCs
No elevation caspase[3] activation was observed in DCX+ cells in the dentate gyrus (DG) of HMFexposed mice compared to GMF-exposed controls (Fig. 1i, j), which excluded the involvement of apoptosis on reduction of neurogenesis

Summary

Introduction

Adult hippocampal neurogenesis contributes to learning and memory, and is sensitive to a variety of environmental stimuli. We showed that male C57BL/6 J mice exposed to HMF by means of near elimination of the geomagnetic field (GMF) exhibit significant impairments of adult hippocampal neurogenesis and hippocampus-dependent learning, which is strongly correlated with a reduction in the content of reactive oxygen species (ROS). These deficits seen in HMF-exposed mice could be rescued either by elevating ROS levels through pharmacological inhibition of ROS removal or by returning them back to GMF. The defective adult hippocampal neurogenesis and cognition in HMF-exposed mice were able to be ameliorated by returning them back to GMF, which is accompanied by elevated ROS levels, but such beneficial effects could be blocked by reducing ROS levels

Methods

Results

Conclusion