TNBS诱导结肠炎小鼠中细菌鞭毛蛋白的表达及其与肥大细胞脱颗粒的关系

目的:研究不同炎症程度下2,4,6-三硝基苯磺酸(TNBS)诱导的结肠炎小鼠的血清及结肠组织中细菌鞭毛蛋白CBir1的表达、肥大细胞脱颗粒的情况及两者的相关性。方法:将SPF级雄性BALB/c小鼠随机分为6组,每组12只,分别是:正常对照组、生理盐水组、50%乙醇组、50%乙醇+TNBS组、50%乙醇+TNBS+酮替芬组及50%乙醇+TNBS+脂多糖(LPS)+卵清蛋白(OVA)组,同时对小鼠进行疾病活动指数(DAI)评分。分组处理后第22天处死并提取小鼠的血清及结肠组织,采用组织损伤指数(HI)评分标准对小鼠结肠进行组织病理评估,采用ELISA法检测抗-CBir1、组胺以及肥大细胞类胰蛋白酶(MCT)在小鼠血清中的浓度,并用免疫组化法检测小鼠结肠组织中CBir1、Toll样蛋白受体5(TLR5)及MCT的表达。结果:TNBS诱导组的DAI评分和HI评分,且CBir1、TLR5、MCT、抗-CBir1和组胺在肠黏膜和血清中的表达明显高于正常对照组(P0.05);50%乙醇+TNBS组上述数值除TLR5外均低于50%乙醇+TNBS+LPS+OVA组(P0.05);50%乙醇+TNBS组上述数值除MCT外则均高于50%乙醇+TNBS+酮替芬组(P0.05);生理盐水和50%乙醇组小鼠与正常对照组小鼠比较,上述数值差异无统计学显著性。将TNBS诱导模型组小鼠血清中抗-CBir1与MCT的浓度进行相关性分析,结果提示两者呈正相关(r=0.751,P0.01);此外,小鼠的血清中抗-CBir1与组胺的浓度亦呈正相关(r=0.648,P0.01)。结论:TNBS诱导结肠炎炎症程度越重的小鼠,其体内CBir1的表达量越高,同时肥大细胞脱颗粒作用也越明显。TNBS诱导结肠炎小鼠体内CBir1的表达量与肥大细胞脱颗粒作用呈正相关性。

Pathogenic effect of bacterial flagellin in TNBS-induced colitis in mice

AIM: To detect the expression of CBir1 in the serum and colon tissue and mast cell degranulation in the tissue of 2,4,6-trinito-benzene-sulfonic acid (TNBS)-induced colitis in mice with different interventions. ME-THODS: SPF male BALB/c mice were randomized into 6 groups (12 mice in each group):normal control group, normal saline group, 50% alcohol group, 50% alcohol+TNBS group, 50% alcohol+TNBS+lipopolysaccharide (LPS)+ovalbumin (OVA) group and 50% alcohol+TNBS+ketotifen group. Corresponding treatment was given to each group, and the disease activity index (DAI) of the mice was evaluated. The mice were sacrificed on day 22 after treatment. The colon tissues were evaluated by histological index (HI) scoring. Serum concentrations of anti-CBir1, mast cell tryptase (MCT) and histamine were measured by ELISA. The expression of CBir1, toll-like receptor 5 (TLR5) and MCT in the colon tissues was detected by immunohistochemistry. RESULTS: Compared with the normal control group, the DAI score, HI score and CBir1, anti-CBir1, MCT, TLR5, histamine concentrations in colon tissues and serum were all significantly higher in 50% alcohol+TNBS group, 50% alcohol+TNBS+ketotifen group and 50% alcohol+TNBS+LPS+OVA group (P<0.05). The DAI score, HI score and anti-CBir1, CBir1, MCT, histamine levels in 50% alcohol+TNBS group were lower than those in 50% alcohol+TNBS+LPS+OVA group (P<0.05). The DAI score, HI score and anti-CBir1, TLR5, histamine, CBir1 Levels in 50% alcohol+TNBS group were higher than those in 50% alcohol+TNBS+ketotifen group (P<0.05). Normal saline group and 50% alcohol group had no statistically significant difference in comparison with normal control group. In TNBS model group, serum concentration of anti-CBir1 was positively correlated with MCT concentration (r=0.648, P<0.01) and histamine concentration (r=0.751, P<0.01). CONCLUSION: The heavier degree of inflammation in TNBS-induced colitis, the higher levels of the CBir1 and the degranulation of mast cells. There is a positive correlation between the expression of CBir1 and the degranulation of mast cells in TNBS-induced colitic mice.