Abstract
BACKGROUND: Major depression (MD) is caused by both genetic and environmental factors. Epigenetic mechanisms, particularly DNA methylation (5mC) and hydroxymethylation (5hmC), are thought to mediate gene - environment interactions. However, findings in mouse models remain dispersed. OBJECTIVE: This review evaluates the studies on 5mC and 5hmC in mouse models of depression. METHODS: We systematically searched PubMed, Scopus, and Web of Science using terms related to 5mC/5hmC, depression, and mouse, until December 2024. We grouped the articles as candidate, global, cellular, and comprehensive studies and summarized the findings accordingly. RESULTS: Sixty-eight studies met inclusion criteria. The main findings were environmental models, especially chronic stress paradigms, which were most frequently used to induce depression models. Candidate gene studies focused on Bdnf and Nr3c1, while global and cellular assays revealed both regional and widespread 5mC/5hmC changes. Genome-wide approaches revealed that epigenetic changes are not limited to isolated loci rather affect broad genomic regions involved in neural development and plasticity. CONCLUSION: This review provides a comprehensive summary of existing research on epigenetic changes in terms of DNA methylation in mouse models of depression. Broader application of standardized, integrative, and cell-type-specific approaches is needed to fully elucidate the role of epigenetic regulation in the pathology of MD.