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BackgroundDaikenchuto (DKT), a gastrointestinal prokinetic Japanese herbal medicine, is prescribed for patients with postoperative ileus (POI) and adhesive bowel obstruction following abdominal surgery. Several mechanisms for the amelioration of POI by DKT have been suggested; however, it has remained unclear whether DKT shows anti-inflammatory effects in POI. In the present study, we investigated the effects of DKT in a mouse POI model and attempted to clarify the detailed mechanisms of action.MethodIntestinal manipulation (IM) was applied to the distal ileum of mice. DKT was administered orally to the animals 4 times before and after IM. Gastrointestinal transit in vivo, leukocyte infiltration, cytokine mRNA expression and gastrointestinal motility were analyzed. We also investigated the effects of the α7nAChR antagonist methyllycaconitine citrate (MLA) on the DKT-mediated ameliorative action against POI, and we studied the effects of DKT on inflammatory activity in α7nAChR knockout mice.ResultsDKT treatment led to recovery of the delayed intestinal transit induced by IM. DKT significantly inhibited the infiltration of neutrophils and CD68-positive macrophages, and inhibited mRNA expressions of TNF-α and MCP-1. MLA significantly reduced the anti-inflammatory action of DKT, and the amelioration of macrophage infiltration by DKT was partially suppressed in α7nAChR knockout mice.ConclusionsIn conclusion, in addition to the gastrointestinal prokinetic action, DKT serves as a novel therapeutic agent for POI characterized by its anti-inflammatory potency. The DKT-induced anti-inflammatory activity may be partly mediated by activation of α7nAChR.

Japanese herbal (Kampo) medicine, Hochuekkito (Bu-Zhong-Yi-Qi-Tang in Chinese, TJ-41) and Juzentaihoto (Shi-Quan-Da-Bu-Tang in Chinese, TJ-48) are well-known Kampo formulas used as tonic. Although these medicines have separately been applied to the patients clinically depending on their symptoms, the differences of the pharmacological activities for these medicines have not been fully understood. TJ-48 and TJ-41 were compared for their effects on antibody response in upper respiratory mucosal immune system in vivo. Oral administration of TJ-41 (100 mg kg−1 per day) to early aged BALB/c mice, which were nasally sensitized with influenza hemagglutinin vaccine, significantly enhanced influenza virus-specific IgA and IgG antibody titers in nasal cavity and sera, respectively. However, oral administration of TJ-48 (100 mg kg−1 per day) failed to show the enhancing activity. TJ-41 increased not only influenza virus-specific IgA antibody titer but also total IgA antibody titer in nasal cavity. The stimulating activity of TJ-41 disappeared after treatment with methotrexate. The present study strongly suggests that TJ-41 can stimulate the mucosal immune system of upper respiratory tract, and results in enhancement of antigen-specific antibody response in upper respiratory mucosal and systemic immune systems.

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BackgroundKososan, a Kampo (traditional Japanese herbal) medicine, has been used for the therapy of depressive mood in humans. However, evidence for the antidepressant efficacy of kososan and potential mechanisms are lacking. Recently, it has been recognized that stress triggers neuroinflammation and suppresses adult neurogenesis, leading to depression and anxiety. Here, we examined whether kososan extract affected social behavior in mice exposed to chronic social defeat stress (CSDS), an animal model of prolonged psychosocial stress, and neuroinflammation induced by CSDS.MethodsIn the CSDS paradigm, C57BL/6J mice were exposed to 10 min of social defeat stress from an aggressive CD-1 mouse for 10 consecutive days (days 1–10). Kososan extract (1.0 g/kg) was administered orally once daily for 12 days (days 1–12). On day 11, the social avoidance test was performed to examine depressive- and anxious-like behaviors. To characterize the impacts of kososan on neuroinflammation and adult neurogenesis, immunochemical analyses and ex vivo microglial stimulation assay with lipopolysaccharide (LPS) were performed on days 13–15.ResultsOral administration of kososan extract alleviated social avoidance, depression- and anxiety-like behaviors, caused by CSDS exposure. CSDS exposure resulted in neuroinflammation, as indicated by the increased accumulation of microglia, the resident immune cells of the brain, and their activation in the hippocampus, which was reversed to normal levels by treatment with kososan extract. Additionally, in ex vivo studies, CSDS exposure potentiated the microglial pro-inflammatory response to a subsequent LPS challenge, an effect that was also blunted by kososan extract treatment. Indeed, the modulatory effect of kososan extract on neuroinflammation appears to be due to a hippocampal increase in an anti-inflammatory phenotype of microglia while sparing an increased pro-inflammatory phenotype of microglia caused by CSDS. Moreover, reduced adult hippocampal neurogenesis in defeated mice was recovered by kososan extract treatment.ConclusionsOur findings suggest that kososan extract prevents a social avoidant behavior in socially defeated mice that is partially mediated by the downregulation of hippocampal neuroinflammation, presumably by the relative increased anti-inflammatory microglia and regulation of adult hippocampal neurogenesis. Our present study also provides novel evidence for the beneficial effects of kososan on depression/anxiety and the possible underlying mechanisms.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-017-0876-8) contains supplementary material, which is available to authorized users.