Expression of phosphatidylinositol 3-kinase and effects of wortmannin on the expression of tumor necrosis factor-alpha in ulcerative colitis

Abstract

To elucidate the role of phosphatidylinositol 3-kinase (PI3K)/Akt in the pathogenesis of ulcerative colitis (UC) and provide experimental evidence that PI3K inhibitor wortmannin can be used as a possible novel approach for treatment of UC. Samples of intestinal mucosa were collected from 30 UC patients, 22 males and 8 females, aged 35 +/- 11, during enteroscopy. Samples of normal intestinal mucosa 10 cm beyond the cancerous tissues were collected from 15 patients with intestinal cancer, 9 males and 6 females, aged 40 +/- 9, as normal controls. The samples underwent pathological examination and immunohistochemistry. Another tissues of intestinal mucosa were cultured and divided into 3 groups: UC + wortmannin group, (n = 10, wortmannin, an inhibitor of PI3K/Akt pathway, of the concentration of 0.002 nmol/microl was added), UC control group (n = 10, without addition of wortmannin), and peri-cancer normal intestinal tissue group (n = 10). 4.5 hours after the culture, immunohistochemistry was used to detect the expression of phosphorylated Akt (p-Akt) in the intestinal mucosa and ELISA was used to detect the content of tumor necrosis factor (TNF-alpha) in intestinal mucosa. (1) The A value of p-Akt in the intestinal mucosa of the UC control group was 73.6 +/- 5.2, significantly higher than that of the normal control group (18.0 +/- 2.6, P < 0.05), the positive area of the UC control group was 720 +/- 58, significantly larger than that of the normal control group (133 +/- 29, P < 0.05). (2) The level of TNF-alpha in intestinal mucosa of the UC + wortmannin group was 135 +/- 11, significantly lower than that of the UC control group (296 +/- 39, P < 0.05), however, still significantly higher than that of the normal control group (26 +/- 5, P < 0.05). (3) The A value of p-Akt in the intestinal mucosa biopsy specimens of the UC + wortmannin group was 35.3 +/- 5.6, significantly lower than that of the UC control group (72.3 +/- 6.2, P < 0.05), however, still significantly higher than that of the normal control group (18.0 +/- 2.2, P < 0.05); and the positive area of the UC + wortmannin group was 351 +/- 50, significantly lower than that of the UC control group (716 +/- 94, P < 0.05), however, still significantly higher than that of the normal control group (129 +/- 30, P < 0.05). (1) PI3K/Akt signal transduction pathway is a critical factor in regulating the expression of pro-inflammatory cytokine, and plays a role in the pathogenesis of UC. (2) Decreasing the levels of relevant cytokines in UC by inhibiting PI3K/Akt signal transduction pathway, wortmannin may be a novel approach for the treatment of UC.