title: Repeated Water Avoidance Stress Alters Mucosal Mast Cell Counts, Interleukin-1β Levels with Sex Differences in the Distal Colon of Wistar Rats.
abstract: OBJECTIVE
  This study was aimed at evaluating differences in the effects of repeated water avoidance stress (rWAS) on colonic movement, mucosal mast cell counts, cytokine levels, and visceromotor response (VMR) to colorectal distension (CRD) in rats of both sexes.
  
  
  METHODS
  Wistar rats were divided into stress and no-stress groups. Rats in the stress group were exposed to rWAS (1 hr/day) for 10 days. Mucosal mast cells were immunohistochemically stained with anti-mast cell tryptase antibody and counted. The colonic mucosal cytokine levels were measured with enzyme-linked immunosorbent assay. The VMR to CRD (visceral analgesia) was assessed by using a barostat and noninvasive manometry.
  
  
  RESULTS
  The mean number of fecal pellets in the rWAS group increased significantly as compared with that in the no-stress group in both sexes. After adjustment for body weight, the female rats had a significantly higher pellet output than the male rats. The mucosal mast cell count of the female rWAS group was higher than that of the male rWAS group (13.0 ± 0.9 vs 8.8 ± 0.6;P< 0.001). The colonic mucosal interleukin-1β level was also higher only in the female rats of the rWAS group than in those of the no-stress group. On days 10 and 11, a decrease in VMR to CRD was observed at 40 and 60 mmHg in both sexes of the rWAS group, without a sex-based difference.
  
  
  CONCLUSIONS
  The colonic response to stress appeared to be more sensitive in the female rats than in the male rats. However, stress-induced visceral analgesia had no sex-related difference and the underlying mechanism needs to be further evaluated.
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.|Department of Internal Medicine, Keimyung University School of Medicine, Daegu, Korea.
authors.forename: Ju Yup
authors.initials: JY
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Nayoung
authors.initials: N
authors.lastname: Kim
authors.affiliation: Department of Gastroenterology and Digestive Disease Research Institute, Wonkwang University School of Medicine, Iksan, Jeollabuk-do, Korea.
authors.forename: Yong Sung
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Ryoung Hee
authors.initials: RH
authors.lastname: Nam
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Min Hee
authors.initials: MH
authors.lastname: Ham
authors.affiliation: Department of Pathology, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Lee
authors.affiliation: Department of BioNano Technology and Gachon BioNano Research Institute, Gachon University, Seongnam, Gyeonggi-do, Korea.
authors.forename: Wonjun
authors.initials: W
authors.lastname: Jo
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Youngkwang
authors.initials: Y
authors.lastname: Shim
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Yoon Jin
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Yoon
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Cheol Min
authors.initials: CM
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, Gyeonggi-do, Korea.
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
keywords: Cytokines; Mast cells; Water avoidance stress