Abstract: Objective To establish a diagnostic model for diffuse axonal injury （DAI） by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry （MALDI-TOF-MS）. To screen the proteins or peptides associated with DAI for providing the biomarkers with theoretic foundation. Methods Fifteen male Sprague-Dawley rats were randomly divided into DAI group （n=10） and control group （n=5）. The protein or peptide expression profiles of rat brain stem were detected by MALDI-TOF-MS. ClinProTools 2.2 software was used to find specific peaks, and a diagnostic model was established by the genetic algorithm. Results There were significant differences in 61 peaks of DAI group （P<0.05）, 9 peaks were down-regulated and 52 up-regulated. The diagnostic model was established based on 5 different peaks. The specificity and sensitivity of cross validation was 96.14% and 95.98%; while the specificity and sensitivity of blind validation showed was 73.33% and 70.00%, respectively. Conclusion A specific and sensitive diagnostic model of DAI can be established by MALDI-TOF-MS to provide a potential value for determining DAI in forensic practice.

Key words: forensic pathology, diffuse axonal injury, mass spectrometry, matrix-assisted laser desorption-ionization, brain stem, rats