Neuronal activity is the key modulator of nearly every aspect of behavior, affecting cognition, learning, and memory as well as motion. Hence, disturbances of the transmission of synaptic signals are the main cause of many neurological disorders. Lesions to nervous tissues are associated with phenotypic changes mediated by astrocytes becoming reactive. Reactive astrocytes form the basis of astrogliosis and glial scar formation. Astrocyte reactivity is often targeted to inhibit axon dystrophy and thus promote neuronal regeneration. Here, we aim to understand the impact of gravitational loading induced by hypergravity to potentially modify key features of astrocyte reactivity. We exposed primary murine astrocytes as a model system closely resembling the in vivo reactivity phenotype on custom-built centrifuges for cultivation as well as for live-cell imaging under hypergravity conditions in a physiological range (2g and 10g). We revealed spreading rates, migration velocities, and stellation to be diminished under 2g hypergravity. In contrast, proliferation and apoptosis rates were not affected. In particular, hypergravity attenuated reactivity induction. We observed cytoskeletal remodeling of actin filaments and microtubules under hypergravity. Hence, the reorganization of these key elements of cell structure demonstrates that fundamental mechanisms on shape and mobility of astrocytes are affected due to altered gravity conditions. In future experiments, potential target molecules for pharmacological interventions that attenuate astrocytic reactivity will be investigated. The ultimate goal is to enhance neuronal regeneration for novel therapeutic approaches.

Biological experiments under altered gravity conditions as encountered on sounding rockets often require automated in-flight chemical fixation under the challenging environmental and operational constraints, as accompanying any spaceflight mission. Enabling in-flight fixation while maintaining laboratory-equivalent cultivation conditions from ground handling to recovery poses significant challenges for reliability and reproducibility of experiment scenarios. A common flight-qualified architecture can address these constraints by enforcing controlled environmental and operational execution while decoupling sample-dependent fixation configurations through modular payload integration. This work describes a reusable, automated and standardized fixation payload platform designed to host interchangeable, pre-qualified chemical fixation payloads for biological experiments on a variety of platforms to achieve altered gravity. The module provides a standardized mechanical, thermal and electrical architecture for the integration and operation of experiments employing either adherent or suspension-based cells within a single flight-qualified unit, independent of the specific fixation configuration required. Hardware and operational performance were qualified within the German Aerospace Center’s (DLR) Materialphysikalische Experimente unter Schwerelosigkeit (MAPHEUS®) sounding rocket program. Laminar In-flight Fixation Technology (LIFT) was successfully flown across several missions and payload configurations, in-flight data demonstrate reliable execution of fixation procedures, stable thermal regulation, a pressure-stabilized internal environment and automated housekeeping data acquisition. The presented work establishes LIFT as a versatile, spaceflight-proven module to carry out a wide variety of cell culture experiments, allowing customizable in-flight fixation of samples as well as their monitoring within a common architecture.