Effects of Kampo administration on gene expression levels in the hippocampus of SAMP8 mice.

Age-related psychological frailty, including depression, has been demonstrated to be associated with an increased risk of later dementia and therefore it needs to be corrected as early as possible. The Kampo medicines juzentaihoto(JTT) and ninjinyoeito(NYT) are used for physical frailty in the elderly, and NYT in particular is expected to be useful for psychological frailty as well. However, the mechanisms of action of these two herbal medicines, which are similar in efficacy, remain unclear. In this study, to clarify the site of action of the two Kampo medicines in the hippocampus, we confirmed the effects of the Kampo medicines on 19-week-old SAMP8 mice, a model of early aging in which depression-like behavior begins to appear, were confirmed by analyzing changes in gene expression levels from RNA-sequencing of the hippocampus. Given the established role of neuroinflammation as a contributing factor to psychiatric disorders, including depression, the present study also administered lipopolysaccharide, a Gram-negative cellular endotoxin, to confirm the effects of Kampo medicine during the induction of acute inflammation.