Diabetes mellitus (DM) has reached pandemic prevalence, significantly impacting global health. Accumulating evidence has highlighted a bidirectional relationship between diabetes and depression, with blood-brain barrier (BBB) disruption playing a pivotal role in the pathogenesis of and therapeutic approaches to both disorders. Mesenchymal stem cells (MSCs) have emerged as a promising cell-based therapeutic strategy for DM; however, their potential to mitigate DM-associated emotional deficits rem...