Objective To investigate and validate the changes of miRNA molecular markers in whole blood of mice after exposure to different doses of ⁶⁰Co γ-rays, and to provide an experimental basis for establishing miR-122-5p as a biomarker of radiation damage.

Methods The whole body of BALB/c mice and human peripheral blood were irradiated with ⁶⁰Co γ-rays at different doses (0, 1, 2, 4, and 6 Gy). Leukocytes were isolated from the eyeball blood of mice after 4 h irradiation for high-throughput sequencing, and then the radiation-sensitive miRNAs were screened by bioinformatics, followed by target gene prediction and functional pathway analysis. Quantitative PCR (qPCR) was used to detect the expression changes of radiation-sensitive miRNAs in the whole blood leukocytes of mouse and peripheral-blood lymphocytes of human.

Results The sequencing result showed a total of five radiation-sensitive miRNAs were obtained with statistical significance (P < 0.05), which were miR-150-5p, miR-150-3p, miR-6916-5p, miR-122-5p, and miR-212-3p, respectively. Bioinformatics result indicated that the target genes of the radiation-sensitive miRNAs were mainly involved in the AMPK signaling pathway, apoptosis, autophagy, and the PI3K-Akt signaling pathway. qPCR result showed that the expression of miR-150-5p and miR-122-5p had significant dose-response effects in the whole blood leukocytes of mouse and peripheral-blood lymphocytes of human.

Conclusion miR-122-5p is a potential biomarker of radiation-induced damage.