Objective

2

To explore the antidepressant effect of

Sophora flavescens

seed extract and its molecular mechanism.

Method

2

A mouse depression model was established by intraperitoneal injection of lipopolysaccharide（LPS）， and normal group， model group， fluoxetine group（2.5 mg·kg

-1

）， and

S. flavescens

seed low， medium and high dose groups（200， 400， 800 mg·kg

-1

） were set up for 7 d of consecutive gavage. Then the antidepressant effect of

S. flavescens

seed extract was evaluated by using open field test， elevated plus maze test and forced swimming test. Pathological morphological changes in the hippocampal tissue was observed by hematoxylin-eosin（HE） staining. Protein expression levels of G

1

/S-specific cyclin D

1

（Cyclin D

1

）， Wnt1，

β

-catenin and phosphorylated glycogen synthase kinase-3

β

（p-GSK-3

β

） in mouse brain tissues were detected by Western blot. Hippocampal cell apoptosis was detected by terminal deoxynucleotidyl transferase mediated deoxyuridine triphosphate（dUTP） nick end labeling（TUNEL）.

Result

2

The results of mouse behavioral experiments showed that compared with the normal group， the speed of movement in the open field and the distance of movement in the central area of the open field， and the time spent on the open arms of the elevated plus maze were significantly reduced in the model group（

P

<

0.01）， while immobility time in the forced swimming test was significantly increased（

P

<

0.05）. Compared with the model group， the

S. flavescens

seed medium and high dose groups had increased speed of movement in the open field test and time spent on the open arms of the elevated plus maze test（

P

<

0.05，

P

<

0.01）， and decreased immobility time in the forced swimming test（

P

<

0.05）， the distance of movement in the central area of the open field test increased in the high dose group（

P

<

0.05）. HE staining results showed that compared with the normal group， the hippocampal neuron structure of mice in the model group was damaged. Compared with the model group， after treatment of

S. flavescens

seed extract， the pathological state of the mouse hippocampal neuron structure was alleviated， and the neurons increased， were neatly arranged， and the cytoplasm was clear. Western blot results showed that the protein expression levels of Wnt1 and

β

-catenin in mouse brain tissue were significantly decreased（

P

<

0.01）， while the protein expression levels of Cyclin D

1

and p-GSK-3

β

were significantly increased（

P

<

0.01） after LPS injection. Compared with the model group， protein expression levels of Wnt1 and

β

-catenin in brain tissue of

S. flavescens

seed medium and high dose groups were significantly increased（

P

<

0.01）， while the protein expression levels of Cyclin D

1

and p-GSK-3

β

were significantly decreased（

P

<

0.01）. TUNEL staining results showed that the hippocampal cell apoptosis rate in the model group was significantly increased compared with that of the normal group（

P

<

0.01）， while the hippocampal cell apoptosis rate in the

S. flavescens

seed medium and high dose groups was significantly decreased compared with that of the model group（

P

<

0.01）.

Conclusion

2

S. flavescens

seed extract can effectively improve the severity of depression in LPS-induced depressed mice， and its molecular mechanism is related to the regulation of neuroinflammation and hippocampal neuronal apoptosis mediated by Wnt/

β

-catenin signaling pathway.