Antiulcerative properties of bovine α-lactalbumin

The capacity of α-lactalbumin to protect the rat stomach mucosa against ulcerative lesions caused by indomethacin or absolute ethanol was investigated. An α-lactalbumin prepared in the laboratory by anion exchange and molecular exclusion chromatography (Lab.α-La) and a commercial α-lactalbumin (Comm.α-La) were compared with a saline control. Comm.α-La offered 44% protection versus Lab.α-La 12%, in the indomethacin model. For absolute ethanol, no statistical difference was found in the inhibition of the development of ulcerative lesions for the two α-lactalbumins, ranging from 32% to 50%. The content of prostaglandin E2 (PGE2) and mucus increased in the mucosa after α-La intubation, suggesting that the protein protects the mucosa via stimulation of PGE2 and mucus production. Blocking free sulfhydryl groups by in vivo N-ethylmaleimide alkylation caused an increase in mucosal ulcerative lesions, suggesting the importance of sulfhydryl compounds in the gastric mucosa protection.