Serum interleukin-1 receptor antagonist is an early indicator of colitis onset in Gαi2-deficient mice

AIM： To study the serum concentration of IL-1β, IL-1 receptor antagonist （IL-1Ra） and IL-18 in Gαi2-deficient mice at the age of 6 （healthy）, 12 （pre-colitic） and 24 wk （coUtic） and in healthy control mice. METHODS： At the time of killing, serum samples were collected and IL-1β, IL-1Ra and IL-18 levels were measured using enzyme-linked immunosorbent assays. RESULTS： Serum concentration of IL-1Ra was significantly increased in pre-colitic （median： 524 ng/L; P= 0.02） and colitic （450 ng/L; P= 0.01）, but not in healthy （196 ng/L） Gαi2-deficient mice as compared with controls （217 ng/L）. Serum concentrations of IL-1β did not differ between Gαi2-deficient mice and their controls, irrespective of age, IL-18 was significantly increased in colitic, but not in pre-colitic mice compared with controls （510 ng/L vs 190 ng/L; P= 0.05）. CONCLUSION： The increased serum concentrations of IL-18 and IL-1Ra in established diseases are suggested as markers of ongoing colitis. Interestingly, the significantly increased serum concentration of IL-1Ra in pre-colitic mice is found to be an early marker of disease progression.