INFLUENCE OF DIETARY-FAT ON DUODENAL RESISTANCE TO ACID

Three experimental diets were prepared from a standard formula plus pu re oleic, linoleic, or eicosapentaenoic acid (2% by weight). Mucosal r esistance to acid was tested in anaesthetised rats fed the experimenta l diets for at least four weeks (60 rats per diet) by duodenal infusio n of HCl (200 to 700 mumol) 30 minutes after pretreatment with either saline or 100 mumol HCl (used as a mild irritant). Rats were killed on e hour after the test and the duodenal damage was assessed 'blindly' u sing a combined macroscopic and histological score. Differences were t ested by analysis of covariance of the dose-response curves. Mucosal r esistance was similar in the three groups when the acid challenge was given after saline pretreatment. Resistance to acid in all three group s was significantly increased by previous exposure to 100 mumol HCl (p <0.01). Interestingly, rats fed a linoleic or eicosapentaenoic supplem ented diet after pretreatment with HCl developed significantly higher resistance to acid than those fed the diet with oleic acid (p<0.05). P retreatment with indomethacin suppressed the difference between diets. In conclusion, dietary polyunsaturated fatty acids enhance duodenal r esistance to acid by potentiation of adaptive cytoprotection.