Abstract
<title>Abstract</title> <p> Background Post-stroke depression (PSD) is a prevalent neuropsychiatric complication after stroke that severely impairs neurological recovery and quality of life. Increasing evidence suggests that persistent neuroinflammation, microenvironmental dysregulation, and impaired neuroplasticity are critically involved in PSD progression; however, effective therapeutic strategies remain limited. Urine-derived stem cells (USCs), a noninvasively accessible subtype of mesenchymal stem cells, possess advantages including convenient collection, robust proliferative capacity, low immunogenicity, and potential for autologous transplantation, highlighting their translational potential. This study aimed to evaluate the therapeutic effects of USCs on PSD and to investigate the underlying mechanisms. Methods A rat PSD model was established by combining middle cerebral artery occlusion (MCAO) with chronic unpredictable mild stress (CUMS) to mimic ischemic brain injury and depression-like behaviors after stroke. Behavioral assessments, histological analysis, immunofluorescence staining, and molecular assays were performed to evaluate the therapeutic effects of USCs <italic>in vivo</italic> . To further explore the mechanisms involved, a lipopolysaccharide (LPS)-stimulated microglial inflammatory model was established <italic>in vitro</italic> . immunofluorescence staining, reactive oxygen species detection, flow cytometry, and RT-qPCR were conducted to assess inflammatory signaling and microglial polarization. Results USCs treatment significantly alleviated depression-like behaviors, preserved brain tissue integrity, improved hippocampal neuronal status, and reduced apoptosis in the ischemic penumbra of PSD rats. In addition, USCs markedly attenuated both central and peripheral inflammatory responses. <italic>In vitro</italic> studies demonstrated that USCs inhibited activation of the NF-κB signaling pathway by suppressing NF-κB phosphorylation, reduced intracellular ROS accumulation, and decreased the expression of pro-inflammatory cytokines, including IL-6 and TNF-α. Furthermore, USCs promoted microglial polarization toward the anti-inflammatory M2 phenotype, thereby reprogramming the neuroinflammatory microenvironment and enhancing neuroprotection. Conclusions USCs ameliorated PSD-related pathological and behavioral alterations through paracrine-mediated anti-inflammatory and neuroprotective effects associated with inhibition of the NF-κB signaling pathway. These findings provide mechanistic evidence supporting USCs as a promising stem cell-based therapeutic strategy for post-stroke neuropsychiatric complications. </p>