Dragon’s blood (DB) has shown a protective effect on neurological diseases. Microgravity (MG) or simulated MG (SMG) can induce blood–brain barrier (BBB) dysfunction, which is a characteristic feature of neurological disorders. This study’s purpose was to evaluate the effect of DB on SMG-induced BBB dysfunction and explore its signaling pathway. Both DB and vitamin C (Vc) were administered orally for tail-suspended rats within 3 weeks. DB and Vc solutions were added to human brain microvascular endothelial cells (HCMEC/D3) cells, which were then exposed to SMG for 24 h. The protective effect of DB was assessed by hematoxylin and eosin and Nissl staining, ultrastructure observation, and permeability in rats. Cell apoptosis and the distribution of tight junction (TJ) and adherens junction (AJ) proteins and filamentous actin (F-actin) were examined in HCMEC/D3. The oxidative stress and inflammation, and TJ and AJ protein expressions were determined in rat brain and HCMEC/D3. The focal adhesion kinase (FAK) signaling pathway proteins were determined. DB protected SMG-induced rat BBB disruption by improving neuronal apoptosis, repairing widened intercellular space, and decreasing BBB permeability. DB effectively relieved SMG-induced HCMEC/D3 damage by inhibiting cell apoptosis and restoring F-actin spindle distribution. High doses of DB upregulated TJ and AJ protein expressions and decreased oxidative stress and proinflammatory cytokine levels in rat brain and HCMEC/D3. DB enhanced the expressions of FAK signal transduction proteins and F-actin/globular actin (G-actin) ratio in rat brain and HCMEC/D3, suggesting that DB promotes actin cytoskeleton polymerization, benefits the endothelial cell–cell and cell–extracellular matrix adhesion, and, in consequence, contributes to BBB integrity.

During space manned missions, radiation is a serious health risk. Radiation can not only directly cause damage to target organs but also trigger side effects to affect nontarget organs. Dragon’s Blood (DB) is a traditional Chinese Dai medicine that has been proven to exhibit radioprotective effects in our lab previously. It can alleviate brain damage, hematopoietic dysfunction, and gastrointestinal damage caused by radiation in rats, but its mechanism of action is not clear yet. In order to study the effect of brain irradiation on the damage to the liver and the protective effects of Dragon’s Blood, herein, liquid chromatography coupled with a mass spectrometer was used to analyze the total differential protein expression in the rat liver after 30 Gy Co⁶⁰γ-ray whole-brain irradiation with/without administration of Dragon’s Blood for 10 days before irradiation. A total of 4557 proteins were identified in the rat liver. A total of 299 coexpressed differential proteins were screened in the RAD/CON group indicating that brain radiation significantly affected the liver’s metabolic system (such as drug and arachidonic acid metabolism), chemical carcinogenesis, and peroxisome process. A total of 85 differential proteins were screened in the DB/RAD group. Results indicated that Dragon’s Blood significantly regulated the expression of 26 proteins to normal levels (Msrb2, Txnrd2, Samm50, Pir, Pex11a, etc.) mainly through regulating the metabolism and redox homeostasis process. The results of molecular docking and network pharmacology found that the main effective radiation protection components in Dragon’s Blood are natural chalcones, flavan, and phenolic derivatives.

P-glycoprotein (P-gp) could maintain stability of the nerve system by effluxing toxins out of the blood-brain barrier. Whether it plays a very important role in drug brain distribution during space travel is not yet known. The present study was aimed at investigating P-gp function, expression, and its interacting proteins in a rat brain under simulated microgravity (SMG) by comparative proteomics approach. Rats were tail-suspended to induce short- (7-day) and long-term (21-day) microgravity. P-gp function was assessed by measuring the P-gp ATPase activity and the brain-to-plasma concentration ratio of rhodamine 123. P-gp expression was evaluated by Western blot. 21d-SMG significantly enhanced P-gp efflux activity and expression in rats. Label-free proteomics strategy identified 26 common differentially expressed proteins (DEPs) interacting with P-gp in 7d- and 21d-SMG groups. Most of the DEPs mainly regulated ATP hydrolysis coupled transmembrane transport and so on. Interaction analysis showed that P-gp might potentially interact with heat shock proteins, sodium/potassium ATP enzyme, ATP synthase, microtubule-associated proteins, and vesicle fusion ATPase. The present study firstly reported P-gp function, expression, and its potentially interacting proteins exposed to simulated microgravity. These findings might be helpful not only for further study on nerve system stability but also for the safe and effective use of P-gp substrate drugs during space travel.

Despite the development and great progress in the field of space biology, the astronauts are still facing many challenges in space. The space environment in which astronauts stay includes microgravity, noise, circadian rhythms disorder, and confinement, which has deep effect both on the physiology and psychology of astronauts. It was reported that long-term flight could cause the astronauts’ anxiety and depression. However, the underlying mechanism is not yet fully understood. Therefore, in the present study, the rat tail suspension model with noise, circadian rhythms, and confinement was employed to simulate complex space environment. We found that the rats exhibited the depressive-like behavior by the sucrose preference, forced swimming, and open-field tests. The membrane proteome of the rat hippocampus was investigated by “SWATH quantitation” technology both in control and simulated complex space environment (SCSE) groups. Out of 4520 quantified proteins, 244 differentially expressed membrane proteins were obtained between the SCSE and control rats, which were functionally enriched in a series of biological processes, such as translation, protein phosphorylation, brain development, endocytosis, nervous system development, axonogenesis, and vesicle-mediated transport. We found a reduction level of neurexin-2, the light, medium, heavy polypeptide of neurofilament, rab 18, synaptogyrin 1, and syntaxin-1A and an increase level of neuroligin-1, munc18, snapin, synaptotagmin XII, complexin-1, etc., which may play a key part in the development of depression. Furthermore, GSK-3β protein was upregulated in mass spectrometry, which was further validated by western blotting. The results of the study do the favor in designing the effective countermeasures for the astronauts in the future long-term spaceflight.