The effects of nuclear factor-kappaB decoy oligonucleotides on dextran sulphate sodium-induced colitis: experiment with mice

Abstract

To investigate the effects of nuclear factor-kappaB (NF-kappaB) decoy oligonucleotide (ODN) on dextran sulphate sodium (DSS)-induced colitis. Nine female BABL/C mice underwent infusion of 0.15 ml normal saline into the distant colon and used as controls (Group 1). Twenty-seven female BABL/C mice were made into DSS-induced colitis models and then randomly divided into 3 groups: Group 2 (underwent infusion of 0.15 ml normal saline into the distant colon), Group 3 (infused with NF-kappaB decoy ODN 25 nmol solved in 0.15 ml), and Group 4 (infused with NF-kappaB scrambled decoy ODN 25 nmol solved in 0.15 ml). Disease active index (DAI) was observed every day. Nine days later the mice were killed and their colons were taken out to undergo histological examination. The tumor necrosis factor (TNF)-alpha level of the colon mucosa was measured by enzyme linked immunosorbent assay (ELISA). NF-kappaB expression was determined by immunohistochemical staining. The distribution of NF-kappaB decoy ODN was investigated by confocal laser microscopy. (1) The DAI scores, histological scores and TNF-a level in the colon mucosa of Groups 2 - 4 were all significantly higher than those of Group 1 (all P < 0.05). The DAI scores, histological scores and TNF-a level in the colon mucosa of Group 3 were all significantly lower than those of Groups 2 and 4 (all P < 0.01). (2) In the tissue sections NF-kappaB p65 was positive mainly in the nucleus in the 3 DSS-treated groups without significant differences among these 3 groups, and was mainly positive in the cytoplasm in the control group. (3) Confocal laser microscopy showed that NF-kappaB decoy ODN could be ingested efficiently into the mucosa and submucous layer of colon. (4) There were no significant differences in the liver function, kidney function, and blood glucose among all groups. NF-kappaB pathway is associated with the pathogenesis of DSS-induced colitis which is very similar to human UC. Blockade of NF-kappaB pathway by NF-kappaB decoy ODN shows protective effect on the mice with DSS-induced colitis.