Synaptic remodeling and functional recovery: Huan Le Ning decoction mitigates perimenopausal anxiety and depression symptoms via hippocampal reorganization

ETHNOPHARMACOLOGICAL RELEVANCE: Huan Le Ning Decoction is a traditional Chinese medicinal formula empirically used to alleviate perimenopausal emotional disturbances. Despite its clinical application, the neurobiological mechanisms remain unclear. AIM OF THE STUDY: Building on prior network pharmacology predictions that prioritized NOTCH1, NID2, and PTGDS as putative targets of HLN bioactive constituents, this study sought to experimentally validate these computational insights and dissect the underlying therapeutic mechanisms in a perimenopausal mouse model, with particular emphasis on hippocampal synaptic plasticity and Notch1 pathway modulation. MATERIALS AND METHODS: The chemical profile of Huan Le Ning Decoction was characterized using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. A perimenopausal depression mouse model was established by combining natural aging with chronic unpredictable mild stress. Mice were treated with low-dose or high-dose Huan Le Ning Decoction, estradiol, or Kuntai Capsule for two weeks. Behavioral tests, serum hormone assays, histopathology, transcriptomics, and molecular validation were performed. A high-performance liquid chromatography fingerprint and voucher specimen (No. HLN-2024-001) were provided for quality control. RESULTS: One hundred eleven bioactive compounds were identified through UPLC-Q-TOF/MS profiling. In parallel, network pharmacology analysis revealed 54 core overlapping targets implicated in perimenopausal mood disturbances, while molecular docking subsequently confirmed robust binding interactions between representative HLN constituents-including luteolin, berberine, and quercetin-and the hub proteins NOTCH1, NID2, and PTGDS. At the organismal level, Huan Le Ning Decoction markedly attenuated anxiety- and depression-like behaviors, restored circulating estrogen and serotonin levels, promoted ovarian follicle preservation, and rescued hippocampal synaptic ultrastructure. Mechanistically, these beneficial effects were accompanied by upregulation of synaptic plasticity-related proteins (postsynaptic density protein 95, synapsin-1, growth-associated protein 43, brain-derived neurotrophic factor), activation of the Notch1/Hes1 signaling axis, increased hippocampal Nid2 expression, and concomitant suppression of Ptgds. CONCLUSIONS: Huan Le Ning Decoction alleviates perimenopausal mood disorders by modulating Nid2and Ptgdsand activating the Notch1/Hes1 pathway to enhance hippocampal synaptic plasticity, supporting its traditional use as a non-hormonal therapeutic option.