Dendrobium officinale flos increases neurotrophic factor expression in the hippocampus of chronic unpredictable mild stress-exposed mice and in astrocyte primary culture and potentiates NGF-induced neuronal differentiation in PC12 cells

Dendrobium officinale flos (DOF) is the flower of Dendrobium officinale Kimura et Migo, which is usually regarded as a by-product of Dendrobii Offcinalis Caulis. Based on its use as an alternative medicine, we evaluated the antidepressant-like effect of DOF extracts on chronic, unpredictable, mild stress-induced, depression-like behaviour in mice and tested the effects of DOF on the regulation of neurotrophic factors in mouse astrocyte primary cultures and PC12 cell lines. Oral treatment with DOF ethanol extract (DOF-E) could alleviate depression-like behaviours in stress-exposed mice, as evidenced by increased sucrose consumption and decreased immobile time in a forced swim test. In the hippocampus, DOF extracts increased the expression of NGF and BDNF, both at the transcriptional and protein levels. In astrocytes, DOF-E increased the expression of NGF and BDNF via a cAMP-dependent mechanism and regulated plasminogen and matrix metallopeptidase 9 (MMP-9), which are related to the metabolic regulation of neurotrophic factors. In PC12 cells, DOF-E induced the expression of neurofilaments and potentiated the induction of neurite outgrowth upon treatment with a low dose of NGF. Based on these findings, DOF might be used as a supplement for antidepressant therapy in patients with depression.