Wound-Healing Capacity of Primary Astrocytes under Altered Gravity Conditions

Glial scarring is the healing response to wounds in the CNS. This process is lead by glial cells, among them astrocytes, which have a major responsibility in the inhibitory properties of glial scars towards axon regeneration. There have been many approaches to help axon regeneration, be it pharmacological stimulation or surgical approaches, such as stem cell grafts. The use of hypergravity as a therapeutic tool is a novel, non-invasive approach that can be combined with already tested methods to aid CNS recovery. This is caused by gravity's effect on individual cells. With the advent of spaceflight, lots of studies examined the effect that microgravity has not only on humans and organs, but also on individual cells. Drastic changes were observed in cells exposed to altered gravity, most often a change in morphology, proliferation and differentiation. These changes were observed in hypergravity as well. While numerous studies have demonstrated that altered gravity has an effect on cells, the underlying mechanisms are still unknown, as different cell types and even different experimental setups lead to different results. However, it is clear that the cytoskeleton plays a role in these changes. It is involved in the processes, where differences were observed, e. g. cell migration, and in many studies, changes could be seen directly using immunofluorescence microscopy. By lowering the migration rate of astrocytes using hypergravity, the process of gial scarring could be slowed down, helping regenerating axons. To test this hypothesis, the migration rate and morphology of astrocytes centrifuged in 2 g was analysed, and compared to astrocytes cultured under normal gravity. The results showed significant morphological differences between the two cell groups, with cells under hypergravity being rounder and having less pseudopodia. Also, these cells were smaller in the first days, but later catched up to the control cells. There was a tendency in wound-healing assays for slower cell migration in 2 g, and again a significant difference in the first few hours of migration, where the 2 g cells were much slower. While more experiments need to be done, this shows a potential for a therapy using hypergravity to slow down the process of glial scarring