TNF and major depressive disorder: Subsequently, we evaluated the therapeutic potential of hUC‐MSCs by comparing the hippocampal whole‐genome transcriptome and hippocampal microglia morphological changes in the rat depression model bofore and after hUC‐MSCs treatment, and the correlation between depression and infammatory cytokines (IL‐6, TNF‐α, IL‐1β) in rats was investigated as well.