Inflammatory bowel disease and inflammatory molecules: chickens, eggs and therapeutic targets

Changes of CD8+CD28- T regulatory cells in rat model of colitis induced by 2,4-dinitrofluorobenzene

AIM: To determine the changes of CD8+ T subsets especially CD8+CD28- T regulatory cells in rat model of experimental colitis induced by 2,4-dinitrofluorobenzene (DNFB).

METHODS: The rat model of experimental colitis was induced by enema with DNFB. Ten days later, colonic intraepithelial and splenic lymphocytes were isolated from colitis animals (n = 16) and controls (n = 8). The proportion of CD8+ T cells, CD8+CD28+ T cells and CD8+CD28- T regulatory cells were determined by flow cytometry.

RESULTS: The model of experimental colitis was successfully established by DNFB that was demonstrated by bloody diarrhea, weight loss and colonic histopathology. The proportion of CD8+ T cells in either splenic or colonic intraepithelial lymphocytes was not significantly different between colitis animals and controls (spleen: 34.6% ± 7.24% vs 33.5% ± 9.41%, colon: 14.0% ± 8.93% vs 18.0% ± 4.06%, P > 0.05). But CD8+CD28- T regulatory cells from colitis animals were significantly more than those from controls (spleen: 11.3% ± 2.26% vs 5.64% ± 1.01%, colon: 6.50% ± 5.37% vs 1.07% ± 0.65%, P < 0.05). In contrast, CD8+CD28+ T cells from colitis animals were less than those from controls (spleen: 23.3% ± 6.14% vs 27.8% ± 9.70%, P = 0.06; colon: 7.52% ± 4.18% vs 16.9% ± 4.07%, P < 0.05). The proportion of CD8+CD28- T regulatory cells in splenic and colon intraepithelial CD8+ T cells from colitis animals was higher than that from controls (spleen: 33.3% ± 5.49% vs 18.4% ± 7.26%, colon: 46.0% ± 14.3% vs 6.10% ± 3.72%, P < 0.005).

CONCLUSION: Experimental colitis of rats can be induced by DNFB with simplicity and good reproducibility. The proportion of CD8+CD28- T regulatory cells in rats with experimental colitis is increased, which may be associated with the pathogenesis of colitis.