Chaihu Shugan San (CSS), a classical formula long employed in the management of major depressive disorder (MDD), has repeatedly demonstrated both efficacy and safety in clinical settings. Impaired angiogenesis has emerged as a critical component of MDD pathology, yet the specific mechanisms by which CSS influences angiogenic processes remain insufficiently defined. To clarify these mechanisms, network pharmacology was first used to map potential angiogenesis-related targets and pathways linking CSS and MDD. Candidate targets were subsequently examined in a chronic unpredictable mild stress (CUMS) mouse model using Western blotting, immunofluorescence, and immunohistochemistry. Mechanistic exploration continued in brain microvascular endothelial cells (BMVECs) treated with CSS-containing serum, assessed through Western blotting and immunofluorescence. Computational analysis highlighted the Silent information regulator protein 1 (SIRT1)/Forkhead box O1 (FOXO1) axis as a central mediator of CSS-associated angiogenesis, a prediction validated experimentally. In CUMS mice, CSS enhanced angiogenic activity, elevated SIRT1, and reduced FOXO1 within the hippocampus. Treatment of BMVECs with 5% CSS-containing serum markedly stimulated cell proliferation, migration, and tube-forming capacity; however, these pro-angiogenic responses diminished when SIRT1 was silenced. CSS-conditioned serum also promoted FOXO1 cytoplasmic translocation via SIRT1 signaling, facilitating FOXO1 degradation. In addition, CSS elevated VEGFA and BDNF levels both in hippocampal tissue from depressive mice and in BMVECs supernatants, two trophic factors central to neurogenesis. CSS supports both angiogenesis and neurogenesis in the hippocampus of CUMS-exposed mice, largely through modulation of the SIRT1/FOXO1 pathway and downstream enhancement of VEGFA and BDNF. These results suggest new avenues for CSS-based therapeutic development and indicate that targeting the SIRT1/FOXO1 axis may hold promise for future MDD treatment strategies.
