Quantitative proteomic analysis of cortex in the depressive-like behavior of rats induced by the simulated complex space environment

Interplay of miRNAs and molecular pathways in spaceflight-induced depression: Insights from a rat model using simulated complex space environment

Depression is a significant concern among astronauts, yet the molecular mechanisms underlying spaceflight-induced depression remain poorly understood. MicroRNAs (miRNAs) have emerged as potential regulators of neuropsychiatric disorders, including depression, but their specific role in space-induced depression remains unexplored. This study aimed to elucidate the involvement of candidate miRNAs (miR-455-3p, miR-206-3p, miR-132-3p, miR-16-5p, miR-124-3p, and miR-145-3p) and their interaction with differentially expressed genes (DEGs) in the neurobiology of spaceflight-induced depressive behavior. Using a simulated space environmental model (SCSE) for 21 days, depressive behavior was induced in rats, and candidate miRNA expressions and DEGs in the cortex region were analyzed through qRT-PCR and HPLC, respectively. Results showed that SCSE-exposed rats exhibited depressive behaviors, including anhedonia, increased immobility, and anxiousness compared to controls. Further analysis revealed increased hydrogen peroxide levels and decreased superoxide dismutase levels in the SCSE group, indicating abnormal oxidative stress in the cerebral cortex. Moreover, miRNA analysis demonstrated significant upregulation of miR-455-3p, miR-206-3p, miR-132-3p, and miR-16-5p expression. Among the DEGs identified, the in silico analysis highlighted their involvement in crucial pathways such as glutamatergic signaling, GABA synaptic pathway, and calcium signaling, implicating their role in spaceflight-induced depression. Protein-protein interaction analysis identified hub genes, including DLG4, DLG3, GRIN1, GRIN2B, GRIN2A, SYNGAP1, DLGAP1, GRIK2, and GRIN3A, impacting neuronal dysfunction functions in the cortex region of SCSE depressive rats. DLG4 emerged as a core gene regulated by miR-455-3p and miR-206-3p. Overall, this study underscores the potential of miRNAs as biomarkers for mood disorders and neurological abnormalities associated with spaceflight, advancing health sciences, and space health care.

Protective effect of Gastrodia elata blume ameliorates simulated weightlessness-induced cognitive impairment in mice

During the long-term orbital flight, exposure to microgravity negatively affects the astronauts' development of cognition, characterized by learning and memory decline. Gastrodia elata Blume (GEB) has a significant protective effect on cognitive impairment and has been used in Asia for centuries as a functional product. A previous study demonstrated that GEB could improve memory loss in mice caused by circadian rhythm disorders. However, the effects of GEB on cognitive dysfunction caused by weightless environments have not been investigated. In this study, mice received daily treatment with GEB (0.5, 1 g·kg^-1d^-1, i.g) and Huperzine A(Hup, 0.1 mg·kg^-1d^-1, i.g) orally until the end of the behavioral test (New object recognition test (NORT). Malondialdehyde (MDA) and nitric oxide (NO) levels were detected by kits, and expression of brain-derived neurotrophic factor (BDNF), protein kinase B (AKT), phosphorylated Akt (P-AKT), synaptophysin (SYN) and postsynaptic density 95(PSD95) in hippocampus were detected by western blotting. The results show that administration of GEB (0.5, 1 g·kg^-1d^-1, i.g) and Hup (0.1 mg·kg^-1d^-1, i.g) remarkably reverse HLS-induced learning and behavioral memory disorders, which were associated with significant changes in MDA and NO levels. Additionally, the protein expressions of BDNF, P-AKT/AKT, SYN, and PSD95 were significantly increased in the hippocampus. In summary, our findings will improve the reference for developing GEB as a functional product that improves memory decline.

A Current Overview of the Biological Effects of Combined Space Environmental Factors in Mammals

Distinct from Earth’s environment, space environmental factors mainly include space radiation, microgravity, hypomagnetic field, and disrupted light/dark cycles that cause physiological changes in astronauts. Numerous studies have demonstrated that space environmental factors can lead to muscle atrophy, bone loss, carcinogenesis, immune disorders, vascular function and cognitive impairment. Most current ground-based studies focused on single environmental factor biological effects. To promote manned space exploration, a better understanding of the biological effects of the spaceflight environment is necessary. This paper summarizes the latest research progress of the combined biological effects of double or multiple space environmental factors on mammalian cells, and discusses their possible molecular mechanisms, with the hope of providing a scientific theoretical basis to develop appropriate countermeasures for astronauts.