Anti-Ulcerogenic Effect of a Whey Protein Isolate and Collagen Hydrolysates Against Ethanol Ulcerative Lesions on Oral Administration to Rats G.A. Castro, 1 J.E. Carvalho, 2 S.V. Tinti, 2 A. Possenti, 2 and V.C. Sgarbieri 1 1 Departamento de Alimentos e Nutric ¸a˜o, Faculdade de Engenharia de Alimentos; and 2 Centro Pluridisciplinar de Pesquisas Quı´micas, Biolo´gicas e Agrı´colas, Universidade Estadual de Campinas, Campinas, Sa˜o Paulo, Brazil ABSTRACT 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 (*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. KEY WORDS:  anti-ulcer mechanism  collagen  mucosa protection  ulcerative lesion  whey protein INTRODUCTION T he gastric mucosa is one of the most important tissues in the organism, because of its function, structure, and the pathological processes that can take place in this tissue. 1 It has been accepted that peptic ulcerogenesis (gastric and duodenal) results from an imbalance between infectious agents, such as the bacterium Helicobacter pylori, and=or aggressive chemical agents and stresses versus protective substances, such as proteins, glutathione, other sulfhydryl group-containing substances, mucus, bicarbonate, prosta- glandins (E 2 ,I 2 ), and certain types of dietary fibers, as well as the blood flow to the mucosal cells. 2–7 Absolute ethanol is an ulcerogenic agent that destroys mucosal cells upon direct contact, 5 independently of gastric acidity. Ethanol initially destroys the stomach-protecting layers and finally reaches the mucosal cell surface, causing cell necrosis and liberation of vasoactive mediators, leading to vasoconstriction, edema, and hemorrhage. 5 Rosaneli et al. 8,9 demonstrated, in rats, the anti-ulcerative properties of a whey protein concentrate, produced in a pilot plant, 10 against two ulcerogenic agents, ethanol and indomethacin. It has been recently shown 11–13 that one of the most anti-ulcerogenic proteins in bovine milk whey is a-lactalbumin; in contrast, b-lactoglobulin has no antiulcer- ogenic effect. 13 Collagen hydrolysates have been reported to be efficiently absorbed 14 and capable of stimulating cell regeneration and extracellular matrix production, as well as cytokine modulation. 15–17 Interestingly, Santos 18 described the action of collagen, extracted from bovine tendons (type I collagen), on the recovery of duodenal mucosa lesions caused by Phaseolus vulgaris lectins. A recently published study 19 demonstrated that both bo- vine and porcine collagen hydrolysates (BCH and PCH, respectively) were effective in protecting gastric mucosa when given to rats prior to intragastric administration of absolute ethanol. Bovine collagen did not present a dose– response correlation in the ethanol model, whereas porcine collagen showed a logarithmic dose–response relation- ship. BCH decreased the ulcerative lesion index (ULI) by 55%, versus a 61% decrease for PCH at the same dosage (750 mg=kg of body weight). No significant differences were found (P > .05) between the hydrolysate and its frac- tions. Therefore, the present study focused on combinations Manuscript received 31 October 2008. Revision accepted 29 April 2009. Address correspondence to: V.C. Sgarbieri, Departamento de Alimentos e Nutric ¸a˜o, Rua Monteiro Lobato, 80, Faculdade de Engenharia de Alimentos (Unicamp), CEP 13083- 862, Campinas, SP, Brazil, E-mail: sgarb@fea.unicamp.br or G.A. Castro, Departamento de Alimentos e Nutric ¸a˜o, Rua Monteiro Lobato, 80, Faculdade de Engenharia de Ali- mentos (Unicamp), CEP 13083-862, Campinas, SP, Brazil, E-mail: zerogeo@uol.com.br JOURNAL OF MEDICINAL FOOD J Med Food 13 (1) 2010, 83–90 # Mary Ann Liebert, Inc. and Korean Society of Food Science and Nutrition DOI: 10.1089=jmf.2008.0277 83