Measuring the Electrophysiological Effects of Space-Related Altered Gravity on Primary Neurons

Abstract

Microgravity, a space related condition where gravitational forces are significantly weaker than on Earth, has modulatory effects on neuronal structure, function, and synaptic density which are all key features of neuroplasticity. However, altered gravitational environments' influence on neuroplasticity remains vastly under-studied. To gain understanding of these mechanisms, we investigated electrophysiological behaviors of embryonic rat cortical neurons (eRCN) under altered gravity environments. We conducted our experiment in two phases; the first phase, the cells experienced one condition of either high or low magnetic force field and the second phase we switched conditions. We switched magnetic field conditions to model leaving Earth’s gravity and returning vice versa, mimicking neural adaptation to microgravity and re-entry. We developed a model of altered gravity by generating a high magnetic force field, which measured 0.563 T, and one low magnetic force field which measured 0.036 T, using neodymium 1.27 cm x 1.27 cm permanent magnets. We cultured the dissociated eRCN’s on 60-electrode microelectrode arrays (MEA). After 12 days in vitro, we incubated half of the cultures with functionalized iron oxide nanoparticles (10 µg/mL), while the rest were used as control. We recorded spontaneous activity in neuronal cultures using the MEA2100 (Multi Channel Systems, Germany) after each change in magnetic field condition. The preliminary results suggest observed changes in spike rate and amplitude between conditions. Our study may provide insight into the mechanisms underlying spaceflight-induced neuroadaptations and inform strategies for controlling behavioral neuronal risks associated in long-duration space travel.