Objective: To investigate the neuroprotective effects and antidepressant mechanism of Buyang Huanwutang. Method: The Kunming mice were randomly divided into normal group

model group

fluoxetine group (3.0 mg·kg-1) and Buyang Huanwu Tang low dose

middle dose and high dose groups (9.0

18.0

27.0 g·kg-1

ig)

n=10 in each group. The drugs were administered by ig 1 h before daily stress

and normal saline with the same volume was given in other groups

for a total of 21 d. The mice models of depression were established by chronic unpredictable mild stress (CUMS); the depression-like behavior of the mice were observed by body weight measurement (BWM)

open field test (OFT) and tail suspension test (TST). The morphological changes of neurons in hippocampas CA3 area were observed by Nissl staining; the apoptosis of hippocampal neurons was observed by TUNEL method; and the ultrastructural changes of the hippocampus were observed by transmission electron microscope. Result: As compared with the normal group. depression-like behavior was found in model group

with decreased body weight

decreased scores of horizontal and vertical motion in OFT

and prolonged motionless time (P < 0.05

P < 0.01); changes of neuronal damage and early apoptosis in hippocampal CA3 area were revealed by Nissl staining and transmission electron microscope; TUNEL method showed that the number of apoptotic neurons in hippocampal CA3 area was increased (P<0.01). As compared with the model group

depression-like behavior was improved in Fluoxetine group and Buyang Huanwutang groups

with increased body weight

increased scores of horizontal and vertical motion in OFT

and less motionless time (P < 0.05

P < 0.01); neuronal damage and early apoptosis in hippocampal CA3 area were reduced in Nissl staining and transmission electron microscope; TUNEL method showed that the number of apoptotic neurons in hippocampal CA3 area was decreased (P<0.01). Conclusion: Buyang Huanwutang could improve the depression-like behavior in mice by reducing neuronal damage in hippocampus CA3 area and inhibiting the neuronal apoptosis

with neuroprotective and antidepressant effects.