Untargeted Metabolomic Signature of Mice with Ischemic Stroke

Background: Ischemic stroke (IS) became the most common type of stroke in 2021, leading to an extreme health burden globally, and has the potential to further increase the burden in the young. However, current therapies for IS are limited, and its mechanism remains unclear. Methods: SPF C57BL/6J male mice were used to establish the middle cerebral artery occlusion (MCAO) model. The Longa's Neurological Deficit Score and TTC staining served as evaluative metrics for the efficacy of the model. Untargeted metabolomics analysis was performed based on LC-MS technology, and PCA, PLS-DA, and KEGG analysis were used to explore the differential metabolites. Results: Compared to the Sham group, the neurological deficit score of the MCAO group was significantly higher at 2 h and 72 h after surgery (p < 0.001). There was no infarct volume in the Sham group, while the infarct volume ratio of the MCAO group significantly increased compared with that of the Sham group. In total, 1836 metabolites were identified overall, and they were clustered into 14 classifications, with "lipids and lipid-like molecules" accounting for the most (34.45%). Compared with the Sham group, 95 metabolites were up-regulated, and 107 metabolites were down-regulated in the MCAO group; 138 of 202 were identified with HMDB numbers. A further clustering and KEGG pathway analysis showed that these 138 metabolites may be involved in lipid metabolism, amino acid metabolism, and nucleotide metabolism. However, FDR was not used as extracting criteria to screen out the differential metabolites, which indicated that the outcomes should be considered for further validation. Conclusions: This discovery-stage untargeted metabolomics analysis suggests that ischemic stroke may be associated with alterations in lipid, amino acid, and nucleotide metabolism in the mouse brain, but these exploratory findings require validation in larger independent cohorts using targeted metabolomics.