Submitted on June 11, 2007
Accepted on September 28, 2008
Hypertonic saline reduces neutrophil-epithelial interactions in vitro and gut tissue damage in a mouse model of colitis
Wolfgang Tillinger1, Declan F. McCole2, Stephen Joseph Keely3, Lone S. Bertelsen2, Paul L. Wolf2, Wolfgang G Junger4, and Kim E. Barrett5*
1 Medicine, Hartmann Hospital, Vienna, Austria
2 Medicine, U of Calif San Diego, San Diego, California, United States
3 Medicine, U of Calif San Diego, San Diego, California, United States; Dept. of Molecular Medicine, Royal College of Surgeons in Ireland, Dublin 9, Ireland
4 Surgery, 8236, University of California San Diego, UCSD Medical Center, San Diego, California, 92103-8236, United States
5 Medicine, UC San Diego, UCSD Medical Center 8414, San Diego, California, 92103, United States; Medicine, UC San Diego, La Jolla, California, United States
* To whom correspondence should be addressed. E-mail: kbarrett{at}ucsd.edu.
Transepithelial migration of polymorphonuclear neutrophils (PMN) plays a crucial role in inflammatory conditions of the intestine, such as inflammatory bowel diseases. Hypertonic saline (HS) exerts various inhibitory effects on PMN function. We hypothesized that HS could inhibit transepithelial migration of PMN and thereby prevent inflammatory events in experimental colitis. Isolated human PMN were treated with HS (40 mM) and their transmigration across a monolayer of T84 epithelial cells was induced by N-formyl-methionyl-leucyl-phenylalanine. Monolayer disruption was assessed by monitoring changes in transepithelial conductance in an Ussing chamber. Colitis in mice was induced by oral administration of dextran sulfate sodium (DSS). Animals were treated with 4 or 8 ml/kg of 7.5% saline i.p. twice daily for 7 days. Controls received equivalent volumes of normal saline (NS, n=6) or no i.p. treatment (DSS, n=12). The severity of inflammation was evaluated based on disease activity index (DAI) and histology score. HS-treatment of PMN in vitro significantly reduced cell migration and the disruption of T84 monolayers compared to untreated control cells (n=5, p < 0.05). This effect of HS was dose-dependent. HS treatment in vivo also reduced colitis-induced gut tissue damage. as indicated by an improved histology score compared to the NS and DSS groups. We conclude that HS inhibits transepithelial migration of PMN in vitro and gut tissue damage in vivo in a mouse model of colitis. Thus HS may have clinical value to reduce PMN-mediated intestinal damage.
