Multiple organ injury in septic rats under weightlessness.

Introduction: As human space exploration advances, the risk of infection faced by astronauts has also become apparent. However, the impact of sepsis on the body under weightlessness remains unclear. Methods: A rat model of sepsis under simulated weightlessness was preliminarily established by combining hindlimb unloading with cecal ligation and puncture. The effects of simulated weightlessness on the early progression of sepsis in rats were systematically evaluated through assessments of mortality, hematological parameters, inflammatory markers, coagulation function, organ function, and histopathological injury. Results: Our results demonstrated that simulated weightlessness reduced the survival rate of septic rats. During the early phase of sepsis, compared with septic rats under normal conditions, those under simulated weightlessness showed significantly upregulated levels of MON, GRA, TNF-α, IL-6, and CRP, and significantly downregulated IL-10, suggesting that weightlessness aggravated the inflammatory storm in septic rats. Meanwhile, in septic rats under simulated weightlessness, PLT was significantly decreased, while PT, APTT, and FIB were significantly increased, indicating that weightlessness aggravated early coagulation dysfunction in septic rats. Furthermore, the significant increases in ALT, AST, BUN, CRER, CK, and LDH, combined with histopathological findings from HE staining of organ sections, suggested that weightlessness aggravated early multiple organ injury (heart, liver, lung, and kidney) in septic rats. Discussion: These findings highlight the necessity of proactive environmental monitoring and rigorous preventive measures for astronauts during space missions. While understanding sepsis mechanisms in weightlessness is vital for emergency preparedness, the precise molecular pathways and effective treatments remain unclear, thus warranting further investigation.