Effect of Bushen Shugan Prescription on Oxidative Stress and TGF-β1/Smad Signaling Pathway in Hippocampus of Senile Depressed Mice / 中国实验方剂学杂志

ABSTRACT

Objective:To observe the changes in oxidative stress and transforming growth factor-<italic>β</italic>₁ （TGF-<italic>β</italic>₁）/Smad signaling pathway in hippocampal tissue of senile depressed mice after chronic unpredictable mild stress and to explore the possible anti-depression mechanism of Bushen Shugan prescription. Method:Ninety five-month-old mice were randomly divided into six groups， namely the normal group， senile depression model group， high-， medium-， and low-dose Bushen Shugan prescription groups， and fluoxetine group， with 15 in each group. Mice in all groups， except for the normal group， were exposed to chronic unpredictable mild stress （CUMS） for inducing the senile depression. Since the first day of modeling， the mice in the high-， medium- and low-dose Bushen Shugan prescription groups were gavaged with 19.5， 9.75， 4.87 g·kg^-1 Bushen Shugan prescription， the ones in the fluoxetine group with 0.033 g·kg^-1fluoxetine， and those in the normal and senile depression model groups with an equal volume of normal saline for 21 successive days. The behavioral responses of mice in each group were evaluated in the open field test （OFT）， and the hippocampal tissues of mice were collected for testing the relevant indexes. The superoxide dismutase （SOD） content was determined by WST-1 method， malondialdehyde （MDA） content by TBA method， glutathione （GSH） content by micro enzyme-linked immunosorbent assay （ELISA）， and mRNA expression of TGF-<italic>β</italic>₁， Smad2， Smad3， and Smad7 by Real-time polymerase chain reaction （Real-time PCR）. Result:Compared with the normal group， the senile depression model group exhibited significantly lowered horizontal and vertical scores in OFT， decreased SOD and GSH contents in hippocampal tissues， elevated MDA （<italic>P</italic><0.05）， up-regulated TGF-<italic>β</italic>₁， Smad2， and Smad3 mRNA expression， and down-regulated Smad7 （<italic>P</italic><0.05）. Compared with the senile depression model group， Bushen Shugan prescription at the high， medium， and low doses and fluoxetine all increased SOD and GSH contents in mouse hippocampal tissues， decreased the MDA content （<italic>P</italic><0.05）， down-regulated the mRNA expression of TGF-<italic>β</italic>₁， Smad2， and Smad3 in hippocampal tissues， and up-regulated the Smad7 mRNA expression （<italic>P</italic><0.05）. The comparison with the high-dose Bushen Shugan prescription group showed that the SOD and GSH contents in hippocampal tissues of mice in the medium- and low-dose Bushen Shugan prescription groups declined significantly， while the MDA contents rose significantly （<italic>P</italic><0.05）. Besides， the mRNA expression levels of TGF-<italic>β</italic>₁， Smad2 and Smad3 in the hippocampal tissues of mice in the medium- and low-dose Bushen Shugan prescription groups were significantly up-regulated， and those of Smad7 were significantly down-regulated （<italic>P</italic><0.05）. Conclusion:Bushen Shugan prescription alleviates the depression symptoms in aged SAPM8 mice possibly by regulating the hippocampal oxidative stress and TGF-<italic>β</italic>₁/Smad signaling pathway.