溃疡性结肠炎磷脂酰肌醇3激酶的表达及其抑制剂对肿瘤坏死因子α表达的影响

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

目的探讨磷脂酰肌醇3激酶(PI3K)/Akt 信号传导通路在溃疡性结肠炎(UC)发病中的作用并为沃特曼宁(wortmannin)作为 UC 治疗新药物提供实验依据。方法收集 UC 患者30例,15例结肠癌旁正常组织作为对照,采用免疫组化法检测 UC 肠黏膜组织中磷酸化 Akt(p-Akt)的表达情况;体外组织培养观察 PI3 K/Akt 信号传导通路抑制剂 wortmannin 对 UC 肠黏膜活检组织肿瘤坏死因子(TNF)-α表达的影响。结果①UC 肠黏膜组织中 p-Akt 的表达明显高于正常对照组(A 值分别为73.6±5.2、18.0±2.6,阳染面积分别为720±58、133±29,均 P<0.05)。②与未用 wortmannin处理的 UC 对照组比较,wortmannin 处理后 UC 肠黏膜组织分泌 TNF-α的水平明显较低(分别为296±39、138±11、26±5,均 P<0.05)。③用 wortmannin 处理后 UC 患者肠黏膜组织中 p-Akt 的表达低于未用 wortmannin 处理的 UC 对照组(A 值分别为:72.3±6.2、35.3±5.6、18.0±2.2,阳染面积分别为716±94、351±50、129±30,均 P<0.05)。结论①PI3K/Akt 信号转导通路参与了促炎性细胞因子 TNF-α的调控与释放,可能在 UC 的发生发展中起着重要作用。②PI3K 的抑制剂 wortmannin 能阻断 PI3K/Akt 信号转导通路,进而减少细胞因子的释放。wortmannin 有可能成为治疗 UC 的新药物。

Objective To elucidate the role of phophatidylinositol 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. Methods Samples of intestinal mucosa were coUeted 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 immunohistochenmistry. 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/μl 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 pospharylated Akt （p-Akt） in the intestinal mucosa and ELISA was used to detect the content of tumor necrosis factor （TNF-α） in intestinal mucosa. Results ①The 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）. ②The level of TNF-α 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）. ② 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 ）. Conclusions 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.