Brain proteome changes after intracerebral hemorrhage in aged male and female mice

Aging is an independent predictor of adverse outcomes after intracerebral hemorrhage (ICH), a stroke subtype with no effective treatment. Despite the expected increase in the incidence of ICH due to population aging and the widespread use of anticoagulants, preclinical studies with aged animal subjects are lacking, and the pathophysiology of ICH in aged subjects has yet to be defined. Herein, we attempt to characterize the brain proteomic changes after ICH using an unbiased label- free quantitative proteomics approach and bioinformatics. To this end, aged male and female mice (18-24 months old) were subjected to sham/ICH. Mice were euthanized on day 3 post-surgery, and ipsilateral brain tissue was collected and subjected to LC-MS/MS analysis. Considering sex as a biological variable, the data derived from males and females were separately analyzed. The proteomics analysis revealed 133 differentially expressed proteins (DEPs) between the sham and ICH groups in male subjects. Among the DEPs, 98 proteins were downregulated, and 35 proteins were upregulated after ICH, compared to sham. In aged female mice, 315 DEPs were identified, of which 221 proteins were downregulated, and 94 proteins were upregulated after ICH compared to sham. The mass spectrometry data was validated using immunohistochemistry or western blot analysis, and the bioinformatics analysis revealed a comprehensive understanding of the signaling pathways associated with ICH. Some DEPs in both aged male and female mice that could play roles in ICH pathology were 14-3-3 proteins and S100-A9. The study also revealed that mitochondrial dysfunction could be a critical regulator of ICH-induced acute brain damage. Overall, the generated proteomics data could help develop hypothesis-driven functional analysis and delineate the complex pathobiology of ICH.