Lactobacillus plantarum C29-fermented defatted soybean (FDS), which contains soyasaponins such as soyasaponin I (SI) and soyasapogenol B (SB) and isoflavones such as genistin (GE) and genistein (GT), attenuated memory impairment in mice. Moreover, in the preliminary study, FDS and its soyasaponins and isoflavones significantly inhibited NF-κB activation in LPS-stimulated microglial BV2 cells. Therefore, we examined the effects of FDS and its constituents SI, SB, GT, and GE on LPS-induced memory impairment in mice. Oral administration of FDS (80 mg/kg), which has higher concentrations of SB and GE than DS, recovered LPS-impaired cognitive function in Y-maze (55.1 ± 3.5%) and passive avoidance tasks (50.9 ± 19.2 s) to 129.2% (74.1 ± 3.5%) and 114.2% (290.0 ± 22.4 s) of normal mice, respectively (P < 0.05). SB and GE (10 μM) also more potently attenuated LPS-impaired cognitive behavior than SI and GT, respectively. SB (10 mg/kg) was the most effective: treatment recovered LPS-impaired spontaneous alternation and latency time to 105.7% and 126.8% of normal control mice, respectively (P < 0.05). SB and GE significantly increased BDNF expression and CREB phosphorylation in LPS-treated mice and corticosterone-stimulated SH-SY5Y cells. Furthermore, SB and GE (10 μM) also significantly inhibited NF-κB activation in LPS-treated mice. These findings suggested that FDS and its constituent soyasaponins and isoflavones may attenuate memory impairment by the regulation of NF-κB-mediated BDNF expression.

In the present study, we investigated the effect of tyndallized HY7712 (tHY7712) on the expression of Th cell specific transcription factors and cytokines in whole-body γ-irradiated mice. Oral administration of tHY7712 strongly recovered the γ-irradiation-suppressed expression of helper T (Th) cell- and regulatory T cell-related transcription factors and cytokines, such as T-bet, Foxp3, IFN-γ, TNF-α, and IL-10, and suppressed Th2 cell-associated transcription factor and cytokine GATA3 and IL-5, respectively. Furthermore, compared with the control, tHY7712 treatment also restored γ-irradiation-impaired natural killer and cytotoxic T cell activities against YAC-1 tumor cells to 97.8% and 98.6%, respectively.

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