DNCB所致结肠炎小鼠血清中细胞因子的活性

Activity of cytokines in dinitrochlorobenzene-induced colitis in mice

目的:观察在实验性结肠炎过程中,小鼠体内促炎细胞因子和抗炎细胞因子活性的变化．方法:BALB／c小鼠33只随机分为对照组(n=15)和实验组(n=18),小鼠先以DNCB涂腹液涂腹致敏,然后实验组以DNCB灌肠液灌肠,对照组以相应体积的乙醇灌肠．每日观察小鼠体质量和大便性状,并采用疾病活动指数(DAI)对动物状态进行评分．所有小鼠处死后观察大体形态改变,并自病变严重部位取组织标本,HE染色,镜下观察结肠的病理学改变．各组小鼠断头取血, 分离出血清,采用双抗体夹心ELISA法测定血清IL-1, TNF-α,IL-6,IL-4,IL-10的吸光度．结果:灌肠24 h后实验组小鼠腹泻百分率达59％,体质量明显减轻,死亡20％．病理学检查对照组小鼠结肠无黏连,黏膜轻度充血,无溃疡形成,镜下组织结构可见, 腺体排列基本整齐;实验组小鼠腺体数目减少,组织结构紊乱,黏膜糜烂,出血、坏死和大面积深层溃疡．与对照组相比,实验组小鼠疾病活动指数(3．82±2．77 vs 1．25±1．65,P<0．05),组织病理学评分(2．47±1．33 vs 0．38+0．72,P<0．05)显著升高;促炎细胞因子IL-1(112．9 ±8.3 ng／L vs 81．2±16．3 ng／L,P<0．01),TNF-a(137．9 ±36．7 vs 110．3±22．4 ng／L,P<0．05),IL-6(48．2±4．3 ng／L vs 36．1±7．2 ng／L,P<0．01)活性亦显著升高,而抗炎细胞因子IL-4(96．7±16．5 ng／L vs 130．1±13．1 ng／L, P<0．01)和IL-10(107．3±31．2 ng／L vs 149．8±45．1 ng／L, P<0．01)活性显著降低．结论:DNCB诱导的结肠炎与促炎细胞因子水平升高, 抗炎细胞因子水平降低有关．

AIM： To observe the changes of serum pro-inflammatory and anti-inflammatory cytokine activities in mice with experimental colitis. METHODS： A total of 33 BALB/c mice were randomly divided into control （n = 15）and experiment group（n = 18）. After sensitized by 2, 4-dinitrochlorobenzene （DNCB） smeared on the abdominal skin, the mice in the experiment group were challenged with DNCB enema, while those in the control group were treated with ethanol. The body weight, stool viscosity and hematochezia were observed and accumulated as disease active index （DAI） score; the colon pathological score was achieved by macropathology and HE staining of section prepared for microscopy. The activity of serum IL-1, TNFα, IL-6, IL-4 and IL-10 was determined. RESULTS： The percentage of diarrhea was 59% in the experiment mice 24 h after DNCB treatment, and serious weight loss was found, 20% mice died. Pathologically, the mice in the control group had normal histological structures and glands, and no ulcer was found except for occasional light mucosal congestion. However, the decrease in the number of glands and disturbance of tissue structure were observed in the mice of experiment group. Moreover, erosion, hemorrhage, necrosis as well as deeper ulcers were easily seen. As compared with those in the control mice, the DAI （3.82 ± 2.77 vs 1.25 ± 1.65, P 〈0.05）, pathologic score （2.47 ± 1.33 vs 0.38 ± 0.72, P 〈0.05） were significantly increased in the experiment mice. The activities of pro-inflammatory cytokines such as IL-1（112.9 ± 8.3 ng/L vs 81.2 ± 16.3 ng/L, P 〈0.01）, TNF-α（137.9 ±36.7 ng/L vs 110.3 ± 22.4 ng/L, P 〈0.05）, and IL-6（48.2 ± 4.3 ng/L vs 36.1 ± 7.2 ng/L, P 〈0.01） were significantly increased, while the activities of anti-inflammatory cytokines such as IL-4 （96.7 ± 16.5 ng/L vs 130.1 ± 13.1 ng/L, P 〈0.01） and IL-10（107.3 ± 31.2 ng/L vs 149.8 ± 45.1 rig/L, P 〈0.01） were markedly lowered. CONCLUSION： The pathological progress of colitis induced by DNCB is possiblely related with the increased activities of pro-inflammatory cytokines and decreased activities of anti-inflammatory cytokines.