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目的 探讨肿瘤坏死因子样配体相关分子1A(TL1A)对慢性实验性结肠炎小鼠结肠组织中Th9活化的影响.方法 间断饮用3%葡聚糖硫酸钠(DSS)建立慢性实验性结肠炎模型.将32只淋系细胞高表达TL1A小鼠和野生型C57BL/6小鼠分为野生型对照组、转基因对照组、野生型模型组和转基因模型组.对照组小鼠饮用蒸馏水.模型组小鼠饮用含3% DSS的饮用水.于第29天处死小鼠,测定体质量,记录结肠长度,进行结肠大体评分及疾病活动指数(DAI)评分,H-E染色观察结肠病理学改变,分离肠黏膜固有层单个核细胞(LPMC),应用流式细胞术检测 Th9数量,ELISA法测定血清及LPMC分泌IL-9水平,蛋白质印迹法和实时荧光定量PCR法检测结肠组织中IL-9蛋白质和mRNA的表达水平.采用 t检验和单因素方差分析进行统计学分析.结果 野生型模型组小鼠体质量下降百分比低于转基因模型组[(16.2 ± 1.0)% 比(18.9 ± 1.2)%],差异有统计学意义(t=4.90,P<0.05).转基因模型组小鼠结肠大体形态学评分、DAI评分和病理学评分均高于野生型模型组[分别为(2.80 ± 0.64)分比(1.60 ± 0.31)分,(2.55 ± 0.20)分比(1.58 ± 0.17)分,(11.85 ± 0.86)分比(9.50 ± 0.79)分],差异均有统计学意义(t=4.77、10.45、5.69,P均<0.05).转基因模型组LPMC数高于野生型模型组(3.70× 106± 0.28×106比2.65×106± 0.32×106),差异有统计学意义(t=6.98,P<0.05),转基因模型组结肠组织LPMC中T h9占CD4+T淋巴细胞比例高于野生型模型组[(0.54 ± 0.04)% 比(0.23 ± 0.03)%],差异有统计学意义(t=17.54,P<0.05).转基因模型组血清中IL-9水平高于野生型模型组[(170.23 ± 5.69)pg/mL比(150.62 ± 6.45)pg/mL],差异有统计学意义(t=6.50,P<0.05),转基因模型组LMPC分泌IL-9水平高于野生型模型组[(265.21 ± 8.76)pg/mL比(237.58 ± 10.24)pg/mL],差异有统计学意义(t=5.80,P<0.05).转基因模型组IL-9蛋白质和mRNA表达水平均高于野生型模型组(分别为1.31 ± 0.09比1.18 ± 0.03,8.26 ± 1.13比2.25 ± 0.29),差异均有统计学意义(t=3.88、14.57,P均<0.05).结论 淋系细胞高表达TL1A可促进Th9的分化和IL-9的分泌,进而参与慢性实验性结肠炎的发生.

Objective To investigate the effects of tumor necrosis factor-related ligand-1A(TL1A)on activation of T helper 9(Th9)cells of colonic tissues in chronic experimental colitis mice.Methods The chronic experimental colitis mice model was established with drinking dextran sulfate sodium salt(DSS).A total of 32 lymphocytes TL1A highly expressed mice and wild type(WT)mice were divided into WT control group, transgene control group,WT modeling group and transgene modeling group.The mice of control groups were administrated with distilled water. The mice of modeling groups received 3% DSS in drinking water discontinuously.The mice were sacrificed on 29 days after modeling.Body mass was measured,length of colon was recorded,scores of gross colon and the disease activity index(DAI)were calculated.The colonic morphological changes were observed by hematoxylin-eosin(H-E)staining.The lamina propria mononuclear cells(LPMC)were isolated and the number of Th9 cells was tested by flow cytometry.The levels of interleukin-9(IL-9)in serum and LPMC were detected by enzyme-linked immunosorbent assay(ELISA).The expressions of IL-9 protein and mRNA of the colonic tissues were measured by Western blotting and real-time polymerase chain reaction(PCR),respectively.T test and single factor analysis of variance were performed for statistical analysis.Results The percentage of body mass loss of WT modeling group was lower than that of transgene modeling group(16.2% ± 1.0% vs 18.9% ± 1.2%),and the difference was statistically significant(t=4.90, P<0.05).The scores of gross colon,DAI and pathology of transgene modeling group were all higher than those of WT modeling group(2.80 ± 0.64 vs 1.60 ± 0.31,2.55 ± 0.20 vs 1.58 ± 0.17,and 11.85 ± 0.86 vs 9.50 ± 0.79),and the differences were statistically significant(t=4.77,10.45 and 5.69,all P<0.05).The number of LPMC in transgene modeling group was higher than that of WT modeling group(3.70×106± 0.28×106vs 2.65×106± 0.32 × 106)and the difference was statistically significant(t= 6.98,P< 0.05).The percentage of Th9 in total CD4+T cells of LPMC in colonic tissues of transgene modeling group was higher than that of WT modeling group(0.54% ± 0.04% vs 0.23% ± 0.03%),and the difference was statistically significant(t= 17.54,P< 0.05).The serum IL-9 level of transgene modeling group was higher than that of WT modeling group((170.23 ± 5.69)pg/mL vs(150.62 ± 6.45)pg/mL),and the difference was statistically significant(t= 6.50,P< 0.05).The level of IL-9 secreted by LMPC of transgene modeling group was higher than that of WT modeling group((265.21 ± 8.76)pg/mL vs (237.58 ± 10.24)pg/mL),and the difference was statistically significant(t= 5.80,P< 0.05).The expressions of IL-9 protein and mRNA of transgene modeling group were higher than those of WT modeling group(1.31 ± 0.09 vs 1.18 ± 0.03,and 8.26 ± 1.13 vs 2.25 ± 0.29,respectively),and the differences were statistically significant(t=3.88 and 14.57,both P< 0.05).Conclusion TL1A high expression in lymphocytes can promote Th9 cells differentiation and IL-9 secretion which involved in the genesis of chronic experimental colitis.