丁酸钠与5-氨基水杨酸联合用药对大鼠结肠炎治疗作用及机制

Effects of topical treatment with 5-aminosalicylic acid and sodium butyrate on the expression of trefoil factor 3,interleukin-1β and nuclear factor-kB in trinitrobenzene sulphonic acid induced colitis in rats

目的通过观察联合应用丁酸钠(NaB)与5-氨基水杨酸(5-ASA)灌肠治疗对三硝基苯磺酸(TNBS)诱发的大鼠结肠炎三叶因子3(TFF3)、白细胞介素(IL)-1β及核因子(NF)-kB 表达的影响,阐明NaB 和5-ASA 治疗溃疡性结肠炎的分子机制。方法 40只 Wistar 大鼠均分为4组。采用 TNBS/乙醇灌肠制作大鼠结肠炎模型。制模后第3天,各组分别给予不同处理。A 组给予0.9%氯化钠溶液1ml 灌肠;B 组给予5-ASA 1ml 灌肠(100mg/kg);C 组给予 NaB 1ml 灌肠(80mmol/L,pH 7.0);D 组给予5-ASA 与NaB 各1ml 联合灌肠处理。每天1次,观察大鼠腹泻、便血情况,评价疾病活动指数(DAI),并记录体重改变。分别于制模后第1及第2周,抽取每组大鼠各5只,心脏取血,放射免疫分析(RIA)测定血清 IL-1β浓度。大体及镜下观察肠黏膜损伤及组织学变化并进行评分。同时取结肠病变部位组织,生化法检测髓过氧化物酶(MPO)活性,逆转录-聚合酶链反应检测 TFF3基因表达变化,免疫组化法分析 NF-kB 的组织表达。结果与 A 组比较,用药组 DAI、结肠黏膜大体和组织学损伤评分及 MPO 活性均降低(P<0.05),TFF3表达水平升高(1.98±0.02比1.11±0.06,2.66±0.02比1.25±0.07,P<0.05),促炎因子IL-1β及 NF-kB 水平降低(P<0.05)。还观察到联合应用 NaB 与5-ASA 灌肠的效果优于单独应用 NaB 或5-ASA(P<0.05)。结论联合应用 NaB 与5-ASA 对 TNBS 诱发的大鼠结肠炎有良好的治疗作用,其作用机制与增强 TFF3基因表达、抑制 IL-1β及 NF-kB 表达有关。

Objective To observe the effects of topical treatment with 5-aminosalicylic acid（5-ASA） and sodium butyrate（NaB） on the expression of trefoil factor 3（TFF3）, interleukin-1β（IL-1β） and nuclear factor-κB（ NF-κB） in trinitrobenzene sulphonic acid（TNBS） induced colitis in rats and to define the mechanisms of its therapeutic effects. Methods Forty male Wistar rats, induced colitis by colonic instillation of TNBS, were randomly divided into group A, B, C and D. After the production of colitis, ten rats in each group were given the following topical treatments respectively： group A, normal saline;group B 5-ASA at the dose of 100 mg/kg; group C, NaB at the dose of 80 mmol/L; group D 5-ASA and NaB.Mtimals were sacrificed at the 1st and 2nd week after topical treatment. The macroscopic and histological changes of the colon were evaluated and scored, Myelopemxidase（MPO） activity of the mucosa was detected by biochemcal methods. Expressions of serum IL-1β and tissue NF-κB were detected by radioimmunoassay and i mmunohistochemistry, respectively. Expression of TFF3 mRNA was determined by RT-PCR. Results Compared with that in control group A, expressions of serum IL-1β, tissue NFκB, disease activity index, body weight, macroscopic and histological scores and MPO activity in group B, C and D were significantly decreased （ P 〈 0.05）. Expression of TFF3 mRNA was significantly higher in group B, C and D than in group A（ P 〈 0.05）, The combination of NaB with 5-ASA had more significant effects than normal control group A for TFF3 mRNA expression （ 1.98 ± 0.02 vs. 1.11 ± 0.06 in the 1st week, 2.66 ± 0,02 vs. 1.25 ± 0.07 in the 2nd week, P 〈 0.05,respectively） with improving colitis. Conclusions Topical treatment with 5-ASA and NaB had effects in improving TNBS-induced colitis in rats, the mechanism was related to up-expression of TFF3 mRNA and down-regulation of IL-1β and NF-κB.