Effects of a Casein Hydrolysate Prepared from Aspergillus oryzae Protease on Adjuvant Arthritis in Rats

Abstract

We evaluated the effects of a casein hydrolysate (CH) prepared from Aspergillus oryzae protease on rat adjuvant arthritis, a model of human rheumatoid arthritis. CH was administered orally once a day to the animals for 22 d after the adjuvant injection. CH suppressed swelling in the adjuvant-uninjected hind paws, and a higher dose of CH suppressed the increase in arthritic score and swelling of the adjuvant-injected hind paws. A histopathological examination revealed evidence that the higher dose of CH suppressed the articular changes in the rats. In addition, CH suppressed the production of nitric oxide and prostaglandin E₂ in the plasma of the rats. These results suggest that CH had a suppressive effect on adjuvant arthritis by inhibiting the acute and chronic inflammatory reactions.