Viscous methyl cellulose solution thickens gastric mucosa and increases the number of gland mucous cells in mice.

We have observed a stiffening of the gastric wall in mice following oral administration of viscous methyl cellulose (MC) solution as a vehicle for food chemicals, an effect which has not previously been reported. To further investigate this effect, young male ICR mice(n 48) were divided into four groups (one control and three experimental groups) of twelve mice each. Experimental groups I, II and III were administered 0·2 ml of 0·5% (w/v) MC viscous solution/d via a stomach tube for 2, 3 and 4 weeks, respectively. Stomachs were collected following 12 h fasting. The weight of the stomach and mucosa of seven mice per group was measured, and the mucosa was used for the measurement of 8-oxo-20-deoxyguanosine (8-oxodG). Stomach tissue slices from the remaining five mice per group were stained with haematoxylin and eosin to measure mucosal thickness, and were immunostained with an HIK1083 antibody to determine the number of gastric gland mucous cells. The mucosal thickness of the groups administered the MC solution for 3 and 4 weeks, and the size of the HIK1083-immunostained area of the groups administered the MC solution for 2, 3 and 4 weeks were significantly increased(P,0·01) compared with those of the control group. The amount of 8-oxodG was not significantly affected. These results indicate that oral administration of viscous MC solution leads to the thickening of the gastric mucosa, which may be related to an increase in the number of gland mucous cells.