溃疡性结肠炎大鼠淋巴细胞异常归巢与结肠病变

目的 探讨实验性溃疡性结肠炎大鼠淋巴细胞异常归巢与结肠炎症的关系.方法 60只SD大鼠随机分为对照组、模型组及淋巴细胞归巢干预组(SLC抗体干预),每组20只,观察、比较不同组别结肠黏膜炎症,组织细胞因子的变化,逆转录(RT)-PCR半定量法检测、比较结肠组织中次级淋巴组织趋化因子(SLC)及淋巴细胞归巢受体CCR7的表达;流式细胞仪检测、比较结肠回流血液中CCR7+淋巴细胞的比例.结果 模型组、干预组、对照组大鼠在结肠黏膜炎症评分、组织细胞因子含量上差异有统计学意义;模型组、干预组大鼠结肠黏膜下存在淋巴细胞过度归巢现象;模型组、干预组SLC mRNA的表达量(0.85±0.05,0.77±0.14)均明显高于对照组(0.31±0.11,均P＜0.01),而模型组和干预组间差异无统计学意义(P＞0.05);模型组、干预组CCR7 mRNA的表达量(0.79±0.11,0.39±0.12)均明显高于对照组(0.11±0.03,P＜0.01),模型组与干预组间差异亦有统计学意义(P＜0.05);模型组、干预组结肠静脉回流血中CCR7+淋巴细胞的比例(69%±5%,77%±10%)均明显高于对照组(17%±8%,均P＜0.01),而模型组与干预组间差异无统计学意义(P＞0.05).结论 实验性溃疡性结肠炎大鼠的淋巴细胞异常归巢与结肠黏膜的炎症相关,阻断淋巴细胞异常归巢是减轻结肠黏膜炎症的有效途径之一.

Abnormal lymphocyte homing and colon lesions in ulcerative colitis: experiment with rats

OBJECTIVE: To investigate the relationship between abnormal lymphocyte homing and colon lesions in ulcerative colitis. METHODS: 60 Sprague-Dawley rats were randomly divided into 3 equal groups: model group undergoing enema of dinitrochlorobenzene to establish models of ulcerative colitis and then venous injection of normal saline (NS) once a day for 5 days], lymphocyte homing intervention group undergoing venous injection of secondary lymphoid-tissue chemokine (SLC) antibody, and then venous injection of NS for 5 days], and control group undergoing venous injection of NS for 5 days]. On the 6th day blood samples were collected from the portal vein to isolated lymphocytes. Distant colon was dissected to undergo pathological examination of submucosal aggregated lymphatic follicles, ulceration, and inflammation, thus observing the lymphocyte homing situation. Specimens of colon mucosa underwent detection cytokine of interleukin (IL)-2 and IL-6. RT-PCR was used to detect the mRNA expression of SLC gene and the chemokine receptor CCR7. The proportion of CCR7 positive lymphocytes which drainage from colonic vein were measured by flow cytometry (FC). RESULTS: Abnormal lymphocyte homing phenomenon under colonic mucosa was found in the model and intervention groups. The relative grey degree of SLC gene mRNA expression of the model and intervention groups were 0.85 +/- 0.05 and 0.77 +/- 0.14 respectively, both significantly higher than that of the control group (0.31 +/- 0.11, both P < 0.01), however, without significant difference between the 2 former groups. The relative grey degree of CCR7 mRNA expression of the model group was 0.79 +/- 0.11, significantly higher than that of the intervention groups (0.39 +/- 0.12, P = 0.0429), and both were significantly higher than that of the control group (0.11 +/- 0.03, both P < 0.01). FC showed that the proportion of CCR7(+) lymphocytes drainage from colonic vein of the model and the intervention groups were 69% +/- 5% and 77% +/- 10% respectively, both significantly higher than that of the control group (17% +/- 84%, both P < 0.01), however, without significant difference between these 2 former groups (P = 0.0837). CONCLUSION: Abnormal lymphocyte homing is associated with inflammation of the colonic mucosa. Blocking of the lymphocyte homing is effective in reducing the inflammation of colonic mucosa.