Effects of herbal extracts on mRNA expression of intrinsic antidepressant-related candidate factor BNIP-3 in cultured neuronal and glial cell lines: Relationship with the Kampo concept of Qi

Aim: It has been reported that the expression level of BNIP-3 mRNA increases by antidepressants and Hochu-ekki-To (HET), suggesting that BNIP-3 may be a candidate depression-related factor. Therefore, in order to examine the relationship between BNIP-3 and Qi, the expression levels of BNIP-3 mRNA were examined using 22 newly extracted crude drugs which were selected from the previous library results on 120 crude drugs in the neuronal cell line N18TG-2 and in the glial cell line C6Bu-1. Methods: Based on the results on 120 kinds of crude drugs in a cDNA library, 22 kinds were selected and newly extracted, and then cells were re-treated with them for a secondary assay by real-time polymerase chain reaction (PCR) methods. Results: Many of the herbal medicines contained in HET increased BNIP-3 mRNA expression overall. On the other hand, in the results with especially the neuronal cell line N18TG-2, the herbal medicines that make up Oren-gedoku-To (OGT) and San-o-shashin-To (SOST) strongly showed suppressive effects on the expression. Conclusion: Since HET clinically has the effect of raising mood, while an effect of OGT and SOST is to suppress the rise of mood, the result of this study may be of interest regarding the link between control of the direction of Qi and the expression of BNIP-3 mRNA.