Molecular weight of gastric mucus glycoprotein is a determinant of the degree of subsequent aspirin induced chronic gastric ulceration in the rat.

Mucus was sampled from the gastric mucosal surface of anaesthetised rats. Three weeks later these rats were orally dosed each day with aspirin (375 mg/kg) for six months. Then the number and size of the aspirin induced chronic gastric ulcers were assessed. Gel filtration chromatography of the mucus samples showed that mucus glycoprotein was present in both high and low molecular weight forms. There was a natural variation between individual rats in the percentage of glycoprotein in the high molecular weight form (mean = 58.9%; SD = 9.6%; n = 23). This variation correlated strongly with the degree of subsequent aspirin induced chronic gastric ulceration (r = -0.85, p less than 0.001). This is the first time that a pre-existent variability in a mucosal defence factor has been shown to predict susceptibility of the stomach to chronic ulceration.