[Novaferon ameliorates dextran sulfate sodium-induced colitis and downregulates expression of TNF-α in mice]

To explore the effects of novaferon on dextran sulfate sodium (DSS)-induced colitis and expression of TNF-α in mice and to evaluate the efficacy of novaferon on ulcerative colitis and the possible mechanisms.

A total of 70 BALB/C mice [weight (20.0±2.0) g, 8-week years old, female, pathogen free] were randomly divided into 7 groups: a normal group, a model group, a mesalazine treatment group, a prednisone treatment group, a low-dose novaferon group, a middle-dose novaferon group and a high-dose novaferon group (10 mice per group). The normal group-mice were given distilled water. The ulcerative colitis model was established by treated the mice with 4% DSS for 7 continuous days. At the 8th day, the mice in the all of drug treatment groups were injected corresponding drugs (i.p.). During the experiment, the general situation, daily weight, stool trait and occult blood were recorded, and the mice were killed on the 14th day. The disease activity index (DAI), colon length, histological scores were assessed. Immunohistochemistry was used to measure the expression of TNF-α in colonic mucosa.

1) The mice treated with DSS solution showed diarrhea, mucous stool and bloody stool, and the DAI score increased gradually. The mesalazine, predinison and nofaferon could ameliorate the general situation of the mice, reduce the DAI and histological scores, and reverse the decrease in the colon length. 2) Compared with the model group, the DAI scores were significantly decreased in the novaferon groups (at low, middle or high dose), the mesalazine group or the prednisone group (all P<0.01), but there was no difference among the mesalazine group, the prednisone group and the low-dose novaferon group (all P>0.05). The efficacy of novaferon in the middle-dose group and the high-dose group are better than that in the mesalazine group, the prednisone group and the low-dose novaferon group (all P<0.01). The efficacy of novaferon showed a dose-dependent manner. 3) The injury of colonic mucosa was relatively mild in the novaferon groups (at low-dose, middle-dose or high-dose), the mesalazine group and the prednisone group, and there were partial glands and less inflammatory cells. Compared with the model group, there was statistics difference (all P<0.05). The tissue injury was significantly alleviated, and the DAI score was decreased in the high-dose novaferon group compared the middle-dose novaferon group (P<0.05), but there was no significant difference between the low-dose novaferon group and the middle-dose novaferon group or between the mesalazine group and the prednisone group (both P>0.05). 4) The TNF-α expression was significantly down-regulated in the novaferon groups (at low-dose, middle-dose or high-dose), the mesalazine group and the prednisone group compared with model group (all P<0.01); but there was no significant difference between the mesalazine group and the prednisone group (P>0.05); the decrease of TNF-α expression by novaferon displayed a dose-dependent manner. Compared with the mesalazine group or the prednisone group, the TNF-α expression in novaferon groups at all dosages was dramatically reduced (all P<0.01).

Novaferon can improve the DAI scores and colonic tissue injury in ulcerative colitis induced by DSS in mice, and down-regulate the TNF-α expression in dose-dependent manner.