[Study on effect of total flavonoids of Oldenlendia difflusa on ulcerative colitis and its immunological mechanism]

To observe the effect of total flavonoids of Oldenlendia difflusa (FOD) on NF-kappaB and IL-8, TNF-alpha, IL-10 expressions of ulcerative colitis (UC) model rats, and explore its immunological mechanism of anti-UC.

Sixty Kunming male mice with the average weight of (20 +/- 2) g were randomly divided into six groups. The control group (cont) was orally administered with distilled water. Whereas the remaining five groups were fed with 4% dextran sulphate sodium (DSS) solution for seven days to induce acute UC, and orally administered with the following drugs: distilled water (for the DSS group), SASP at dose of 500 mg x kg(-1) x d(-1) for the DSS + SASP group, FOD at dose of 60 mg x kg(-1) x d(-1) for the DSS + FOD-H group, FOD at dose of 40 mg x kg(-1) x d(-1) for the DSS + FOD-M group, and FOD at dose of 26.7 mg x kg(-1) x d(-1) for the DSS + FOD-L group. During the modeling and drug administration, the mice were scored for DAI. Seven days later, the mice were put to death, and their colonic tissue samples were collected to evaluate colonic mucosal lesions. The NF-kappaB p65, IL-8, TNF-alpha, IL-10 expressions were tested by immunohistochemical staining and ELISA.

Seven-day feeding with 4% DSS solution could successfully induce acute UC in mice. Compared with the cont group, the DSS group showed significantly higher DAI and colonic mucosal lesions, remarkable increase in NF-kappaB p65, IL-8, TNF-alpha expression in colonic tissues, and notable decrease in IL-10 expression (P < 0.05). FOD could prevent acute UC in mice included by DSS. Seven-day administration of 60 mg x kg(-1) x d(-1) or 40 mg x kg(-1) x d(-1) FOD could completely or partially resist the above mentioned changes caused by DSS. Compared with the DSS group, the DSS + FOD-H group and the DSS + FOD-M group showed reduction in colonic mucosal lesions, down-regulation in IL-8, TNF-alpha and NF-kappaB p65 expressions and up-regulation in IL-10 expression (P < 0.05).

FOD could significantly resist UC in mice. Its mechanism may be related to the inhibition of NF-kappaB p65 activation, the reduction of IL-8 and TNF-alpha expressions and the increase in the anti-inflammatory factor IL-10.