Histological examination detected obvious pathological signs of colitis in CMV-scrR circuit-treated IL-10−/− mice, including epithelial hyperplasia, crypt abscesses, ulceration, bowel wall thickening and massive leucocytic infiltration, but the IL-10−/− mice treated with CMV-siRTNF-α and CMV-siRT+B+I circuits exhibited much better consistency and morphology of colons without infiltrating inflammatory cells, and the histological scores of these mice were significantly lower than the CMV-scrR circuit-treated mice (Fig. 9f, g). This evidence concerns the gene IL10 and colitis.