Inhibition of Adenosine Deaminase Attenuates Inflammation in Experimental Colitis
作者:Luca Antonioli、Matteo Fornai、Rocchina Colucci、Narcisa Ghisu、Federico Da Settimo、Gianfranco Natale、Olga Kastsiuchenka、Emiliano Duranti、Agostino Virdis、Cristina Vassalle、Concettina La Motta、Laura Mugnaini、Maria Cristina Breschi、Corrado Blandizzi、Mario Del Taca
DOI:10.1124/jpet.107.122762
日期:2007.8
Adenosine modulates the immune system and inhibits inflammation via reduction of cytokine biosynthesis and neutrophil functions. Drugs able to prevent adenosine catabolism could represent an innovative strategy to treat inflammatory bowel disorders. In this study, the effects of 4-amino-2-(2-hydroxy-1-decyl)pyrazole[3,4- d ]pyrimidine (APP; novel adenosine deaminase inhibitor), erythro -9-(2-hydroxy-3-nonyl)adenine hydrochloride (EHNA; standard adenosine deaminase inhibitor), and dexamethasone were tested in rats with colitis induced by 2,4-dinitrobenzenesulfonic acid (DNBS). DNBS-treated animals received APP (5, 15, or 45 μmol/kg), EHNA (10, 30, or 90 μmol/kg), or dexamethasone (0.25 μmol/kg) i.p. for 7 days starting 1 day before colitis induction. DNBS caused bowel inflammation associated with decrease in food intake and body weight. Animals treated with APP or EHNA, but not dexamethasone, displayed greater food intake and weight gain than inflamed rats. Colitis induced increment in spleen weight, which was counteracted by all test drugs. DNBS administration was followed by macroscopic and microscopic inflammatory colonic alterations, which were ameliorated by APP, EHNA, or dexamethasone. In DNBS-treated rats, colonic myeloperoxidase, malondialdehyde, and tumor necrosis factor (TNF)-α levels as well as plasma TNF-α and interleukin-6 were increased. All test drugs lowered these phlogistic indexes. Inflamed colonic tissues displayed an increment of inducible nitric-oxide synthase mRNA, which was unaffected by APP or EHNA, but reduced by dexamethasone. Cyclooxygenase-2 expression was unaffected by DNBS or test drugs. These findings indicate that 1) inhibition of adenosine deaminase results in a significant attenuation of intestinal inflammation and 2) the novel compound APP is more effective than EHNA in reducing systemic and intestinal inflammatory alterations.
腺苷能调节免疫系统,并通过减少细胞因子的生物合成和中性粒细胞的功能来抑制炎症。能够阻止腺苷分解的药物可能是治疗炎症性肠病的一种创新策略。本研究测试了 4-氨基-2-(2-羟基-1-癸基)吡唑并[3,4-d]嘧啶(APP,新型腺苷脱氨酶抑制剂)、9-(2-羟基-3-壬基)腺嘌呤盐酸盐(ENA,标准腺苷脱氨酶抑制剂)和地塞米松对 2,4-二硝基苯磺酸(DNBS)诱导的结肠炎大鼠的影响。经 DNBS 处理的动物在结肠炎诱导前 1 天开始连续 7 天静注 APP(5、15 或 45 μmol/kg)、ENA(10、30 或 90 μmol/kg)或地塞米松(0.25 μmol/kg)。DNBS会引起肠炎,并导致进食量和体重下降。接受 APP 或 EHNA(而非地塞米松)治疗的大鼠比接受炎症治疗的大鼠摄食量和体重增加得更多。结肠炎会导致脾脏重量增加,而所有试验药物都能抵消这种增加。服用 DNBS 后,大鼠结肠出现宏观和微观炎症性改变,APP、ENA 或地塞米松可改善这些改变。经 DNBS 处理的大鼠结肠髓过氧化物酶、丙二醛和肿瘤坏死因子 (TNF)-α 水平以及血浆 TNF-α 和白细胞介素-6 均升高。所有试验药物都能降低这些噬菌体指数。发炎的结肠组织显示诱导型一氧化氮合酶 mRNA 增高,APP 或 EHNA 对其没有影响,但地塞米松会降低其表达。环氧合酶-2的表达不受DNBS或试验药物的影响。这些研究结果表明:1)抑制腺苷脱氨酶可显著减轻肠道炎症;2)新型化合物 APP 在减轻全身和肠道炎症变化方面比 EHNA 更有效。