Anti-ulcerogenic effect of a whey protein isolate and collagen hydrolysates against ethanol ulcerative lesions on oral administration to rats

The effect of the administration of a whey protein isolate (WPI) and collagen hydrolysates on ethanol-induced ulcerative lesions was studied in rats. WPI and bovine or porcine collagen hydrolysate (BCH and PCH, respectively) were given to rats by gavage. In acute experiments, (single-dose) physiological saline (10 mL/kg of body weight) was used as the negative control, and carbenoxolone (200 mg/kg of body weight) was used as a positive control. Ethanol (1 mL per 250-g rat) was also given by gavage. These treatments reduced the ulcerative lesion index (ULI) in a range of 40-77%, depending on the dosage. Some mixtures of WPI with either PCH or BCH provided results that suggested synergisms between WPI and the collagen hydrolysates. For example, WPI/BCH (in the proportion of 375:375 mg/kg of body weight) decreased ULI by 64%. The mechanism for mucosal protection involved a decrease in plasma gastrin (approximately 40%), a significant increase (50-267%) in mucus production, and a reduction in ULI (percentage) when intragastric administrations were performed after in vivo alkylation by N-ethylmaleimide. Results suggest that gastrin, sulfhydryl substances, and some mechanisms related to mucus production are all involved in gastric ulcer protection against ethanol. The collagen hydrolysates (both PCH and BCH) presented a stronger effect on mucus production; on the other hand, the effect of WPI was also dependent on sulfhydryl compounds, resulting in a more protective effect when the two proteins were administered together.