信号转导与转录活化因子3蛋白在小鼠实验性三硝基苯磺酸结肠炎发病中的作用

The Role of Signal Transducers and Activators of Transcription 3 in the Pathogenesis of Experimental Trinitro-benzene-sulfonic Acid Colitis in Mice

背景:克罗恩病(CD)的病因尚不清楚,有研究认为肠黏膜免疫功能异常导致了CD的发病。目的:研究信号转导与转录活化因子3(STAT3)蛋白在小鼠实验性三硝基苯磺酸(TNBS)结肠炎发病中的作用。方法:建立小鼠实验性TNBS结肠炎模型,实验第3天予STAT3反义寡核苷酸(ASON)灌肠,第7天处死。分离肠黏膜固有层单个核细胞(LPMC),流式细胞仪检测LPMC细胞凋亡,蛋白质印迹分析检测LPMCSTAT3、磷酸化STAT3(pSTAT3)以及凋亡相关蛋白Bcl-2、Bax的表达,酶联免疫吸附测定(ELISA)检测肠组织匀浆中肿瘤坏死因子(TNF)-α、干扰素(INF)-γ等炎性细胞因子的表达。结果:与对照组相比,TNBS结肠炎组炎症肠黏膜LPMCpSTAT3的表达增高,Bcl-2表达增高而Bax表达降低,炎症肠组织TNF-α、INF-γ高表达。以STAT3ASON治疗后,肠黏膜LPMCSTAT3、pSTAT3表达降低,Bcl-2表达降低而Bax表达增高,LPMC凋亡增加,炎症肠组织中TNF-α、INF-γ的表达也明显降低。结论:STAT3通过调节炎性细胞因子的分泌和调控LPMC凋亡相关蛋白的表达,参与了小鼠实验性TNBS结肠炎的发病;抑制STAT3的激活能明显缓解小鼠结肠炎的病情。

Background： The etiology of Crohn＇s disease （CD） is still unknown. It is believed that altered immunological function of intestinal mucosa contributes a significant role to the pathogenesis of CD. Aims： To investigate the role of signal transducers and activators of transcription 3 （STAT3） in the pathogenesis of trinitro-benzene-sulfonic acid （TNBS）- induced experimental colitis of mice. Methods： TNBS-induced experimental colitis was constructed in mice. STAT3 antisense oligonucleotide （ASON） was administered intracolonally on day 3. The mice were sacrificed on day 7. The lamina propria mononuclear cells （LPMC） were isolated from the inflamed mucosa. Apoptosis of LPMC was assessed by FACScan cytofluorometer. Western blot analysis was used to assess the expression of STAT3, pSTAT3, Bcl-2 and Bax. The levels of proinflammatory cytokines tumor necrosis factor （TNF）-α and interferon （IFN）-γ in colonic tissue were measured by enzyme-linked immunosorbent assay （ELISA）. Results： The expression of pSTAT3 in colonic mucosal LPMC of TNBS induced colitis mice increased; the expression of Bcl-2 was up-regulated and Bax down-regulated, while the levels of proinflammatory cytokines TNF-α and IFN-γ, in inflamed colonic tissue increased significantly. In STAT3 ASON-treated mice, the expression of STAT3 and pSTAT3 decreased; Bcl-2 expression increased and Bax expression decreased. Levels of TNF-α and IFN-γ in the inflamed colonic tissue also decreased markedly. Conclusions： STAT3 via modulating the secretion of proinflammatory cytokines and the expression of LPMC apoptosis-related protein, plays a significant role in the pathogenesis of TNBS-induced experimental colitis. Inhibiting the activation of STAT3 can significantly ameliorate the degree of severity of TNBS-induced experimental colitis in mice.