RNA-Seq Reveals Th17 Cell Differentiation Pathway as a Mechanism of Radiation-Induced Brain Injury.

Radiotherapy is a prevalent therapeutic modality for head and neck malignancies; however, it invariably results in radiation-induced damage to normal cerebral tissue, culminating in radiation-induced brain injury (RBI). Despite extensive research on radiation-induced neuroinflammation, the association between RBI and the Th17 cell differentiation pathway remains inadequately understood. C57BL/6 mice underwent a single administration of 30 Gy cranial irradiation to develop the RBI model. Cognitive function was evaluated through the Morris water maze (MWM), open field test, novel object recognition test, and rotarod test. Histopathological alterations in brain tissue were analyzed using hematoxylin and eosin (H&E) staining. Immunofluorescence staining was employed to assess the activation of microglia (IBA-1) and astrocytes (GFAP). RNA sequencing was conducted to identify differentially expressed genes, while Simple Western and qPCR were utilized to examine key signaling molecules involved in Th17 cell differentiation. RBI mice demonstrated marked cognitive deficits, particularly in spatial learning and memory retention. Histological examination indicated activation of microglia and astrocytes within the cortex and hippocampus of irradiated mice. RNA sequencing analysis identified a significant enrichment of the Th17 cell differentiation pathway in the cortex of the RBI group. Further validation through Simple Western and qPCR analyses confirmed the upregulation of TGF-β, IL-6, RORγt, IL-17, and P-STAT3 in the cortex of RBI mice. These findings suggested that the Th17 cell differentiation pathway played a pivotal role in the pathogenesis of radiation-induced brain injury. Neuroinflammation mediated by Th17 cells may be a critical mechanism underlying radiation-induced cognitive dysfunction.