Effect of mild irritant on gastric mucosal offensive and defensive factors.

The effect of hypotonic medium (Distilled water: DW) and hypertonic saline (HS: 5% NaCl) compared to control normal saline (NS) was studied on gastric ulcer induced by aspirin, 6 h cold restraint stress, ethanol, and pylorus ligation in rats. DW did not afford any protection while HS showed significant ulcer protective effects in all gastric ulcer models studied. The cytoprotective effect of HS seemed to be not only due to its effect on gastric acid secretion but also its effect on mucosal defensive factors like enhanced mucin secretion and decreased cell shedding. As determined by radioimmunoassay, DW did not produce any change in the accumulation of PGE and PGI2, while HS increased them significantly in the human gastric mucosal incubates compared to NS. However, in the incubates of human colonic mucosa, both DW and HS showed a significant increase in PGE with a tendency to increase in PGI2 accumulation.