Proteomic Changes in Preterminal Serum Samples of Rhesus Macaques Exposed to Two Different Doses of Acute Lethal Total-body Gamma Radiation

Ionizing radiation exposure induces cellular and molecular damage, leading to a chain of events that results in tissue and organ injury. Proteomics studies help identify, validate, and quantify alterations in protein abundance downstream of radiation-induced genomic changes. The current study strives to characterize and validate the proteomic changes at the preterminal stage (moribund animals) in serum samples collected from rhesus macaques lethally and acutely irradiated with two different doses of cobalt-60 gamma-radiation. Peripheral blood samples were collected prior to exposure, after exposure, and at the preterminal stage from nonhuman primates (NHPs) that did not survive after 7.2 or 7.6 Gy total-body irradiation (LD60-80/60). Using mass spectrometry-based proteomics, we analyzed samples collected at various time points after irradiation. Our findings revealed that radiation induced significant time-dependent proteomic alterations compared to pre-exposure samples. More pronounced dysregulation in pathways related to immune response and hemostasis, specifically platelet function, was present in preterminal samples, suggesting that alterations in these pathways may indicate the preterminal phenotype. These results offer important insights for the identification and validation of biomarkers for radiation-induced lethality that would be of great importance for triage during a radiological/nuclear mass casualty event.