Furthermore, we have compared sex differences in the stress response to rWAS stimulation

Furthermore, we have compared sex differences in the stress response to rWAS stimulation. Psychological stress is known to affect the GI microbiota [9]. For example, 7 day repeated exposure to water avoidance stress (rWAS) has been shown to alter the composition of colonic microbiota [10]. In addition, other psychological stressors have also been demonstrated to reduce microbial species diversity (dysbiosis) and increase pathogenic bacteria in the murine intestine [11, 12]. However, little is known about how psychological stressors induce changes in GI microbiota, and the mechanism by which altered GI microbiota accelerates gut inflammation. Therefore, we investigated the impact of psychological stress on both gut microbiota and the mucosal immune system in the colon to clarify the factors that intensify gut inflammation in this setting. We utilized a T cell receptor alpha chain gene (mice, show differential stress responses in the central nervous system and the gut [17]. We found that C57BL/6 mice showed higher sensitivity to chronic psychological stress as compared with BALB/c mice (data not shown), and therefore our experiments were performed using the B6-mice. Furthermore, Ibuprofen piconol we have compared sex differences in the stress response to rWAS stimulation. In this experiment, plasma corticosterone levels and intestinal permeability were higher in female C57BL/6 mice compared to that of male mice (data not shown). It is suggested that female mice have more sensitivity to psychological stress; therefore, we used female mice in our study. Animals were maintained in ventilated cases (containing autoclaved soft bedding, water, and food), in an environmentally controlled room (23 1C, 12 h light/dark cycle). After the stress session, mice were euthanized by isoflurane inhalation and samples were collected for analysis. All animal experiments were approved by the Institutional Animal Care and Use Committee of Yakult Central Institute (approval number: 13C0091, 14C0130). Repeated water avoidance stress (rWAS) In most previous reports, exposure term of psychological stress in mice was less than 10 days [8, 10C12], and no study has examined the influence of long-term psychological stress on IBD. To elucidate the relationship among chronic psychological stress, GI microbiota, and chronic inflammation, mice were subjected to repeated water avoidance stress (rWAS) for 12 weeks. It was performed between 9:00 am and 2:00 pm for 1 hour per day, and was repeated 5 days per week for 12 weeks (60 times in total). Mice were placed individually on a rectangular platform (3 cm length 3 cm width 6 cm height), which was affixed (in the center) to the bottom of a container (40 cm length 25 cm width 20 cm height). The container was filled with water up to 1 1 cm below the top of the platform. It is known that mice have individual differences in developing colitis between the age of 8 and 20 weeks. Therefore, we selected a 12 week term of rWAS for this study to clarify the influence Ibuprofen piconol of chronic psychological stress on the development of colitis. We also examined two different rWAS protocols, once or five times per week for Ibuprofen piconol 12 weeks, to determine the rWAS frequency appropriate for exacerbating colitis. The result indicated that high frequency rWAS (five times per week) induced more severe colitis, with persistent activation of the hypothalamusCpituitary-adrenal (HPA) axis, compared with low frequency rWAS (once a week) (S1 Fig). Therefore we reasoned that high frequency rWAS was suitable for the purpose of this study. Administration of strain Shirota (LcS) LcS (YIT9029) is one probiotic strains Plau that can survive in the intestine and modulate GI environment. LcS fermented milk ( 5 billion CFU /ml) and the placebo were placed in sealed packs and set on the breeding cages. Instead of water, mice were given 2 mL of either LcS or placebo between 9:00 am and 2:00 pm 5 days a week, for 12 weeks (same time period as the rWAS sessions). Feces from mice that were given LcS fermented milk were collected once a week, and total LcS was measured by the colony detection method. More than 109 CFU of.

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