Neuroinflammatory injury is one of the typical brain injuries after the body is exposed to radiation. It is mainly characterized by the release of inflammatory factors by activated microglia and peripherally invading lymphocytes. To provide early warning for nerve injury and early diagnosis of neurodegenerative diseases, it is of great significance to explore the biomarker candidates of neuroinflammatory injury. This study focused on the screening of small molecular biomarker candidates in peripheral blood from rats with neuroinflammatory injury induced by whole-brain irradiation. The rats were exposed to 0, 10, 10 Â 3, and 30 Gy of cobalt-60 γ-rays. Serum was collected on the 30th day after exposure and analyzed using reversed-phase liquid chromatography and hydrophilic interaction liquid chromatography coupled with highresolution mass spectrometry based on untargeted metabolomics. Biomarker candidates were investigated by comparing the 0-Gy group and three irradiation groups using univariate statistical analysis, principal component analysis, and orthogonal partial least squares discriminant analysis. Eleven biomarker candidates were putatively identified, and four major altered metabolic pathways were found. The screened small molecular biomarker candidates could be used as a useful supplement to traditional biomacromolecule markers and may be valuable for radiation protection, target therapy of inflammatory injury, and discovery of new target drugs for the prevention and cure of related neurodegenerative diseases.

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