Objective To explore the role of mast cells in the pathogenesis of ulcerative colitis in rats with dampness and heat syndrome, and observe the regulatory effect of Huangqin decoction on the mast cells. Methods Rat models of dampness and heat syndrome were established by feeding with high-fat and-sugar chow, maintenance of a hot and humid environment, and intrarectal administration of 2,4,6-trinitro-benzene-sulfonic acid. The model rats were then randomized into the model group (n=12), Huangqin decoction group (n=13) and mesalazine group (n=12). After a one-week treatment, the inflammatory cell infiltration was observed using HE staining, and the number of mast cells was determined using toluidine blue staining. Immunohistochemistry was used to detect the expression of tryptase, and serum IL-4 and IL-6 levels were measured using ELISA. Results Compared with the normal control rats (n=15), the rats in the model group showed obvious inflammatory cell infiltration at the lesion site with significantly increased mast cells and serum IL-6 level (P0.05). Huangqin and mesalazine significantly lessened inflammatory cell infiltration and decreased the mast cell number and serum IL-6 level after a one-week treatment. Conclusion The intestinal mucosal immune cells such as the mast cells play an important role in the pathogenesis of ulcerative colitis associated with dampness and heat syndrome. Huangqin decoction can ameliorate the inflammation, decrease mast cell number and tryptase release, and inhibit IL-6 secretion for treatment of ulcerative colitis in rats with dampness and heat syndrome.%目的 探讨肥大细胞(MC)在湿热型溃疡性结肠炎(UC)发病机制中的作用以及黄芩汤对湿热型UC模型中MC的调节.方法 采用高脂高糖饲料联合高温高湿人工气候模拟法造出湿热型体质,结合三硝基苯磺酸灌肠法诱发UC最终建立湿热型UC大鼠模型;造模成功后将大鼠分为模型组(n=15)、黄芩汤组(n=13)及美沙拉嗪组(n=12),灌胃治疗1周后,采用HE染色法观察病变部位炎症细胞浸润程度,甲苯胺蓝改良染色法检测MC形态、数目及脱颗粒率,免疫组化SP法检测类胰蛋白酶(TA),ELISA法检测血清IL-6.结果 与空白对照组(n=15)相比,模型大鼠结肠病理切片炎症浸润程度、MC数目、TA、IL-6明显升高(P＜0.05);治疗后黄芩汤及美沙拉嗪组以上指标均较模型对照组降低(P＜0.05),且两种药物的效应无明显组间差异(P＞0.05).结论 MC等肠粘膜局部免疫细胞在湿热型UC发病机制中发挥着重要作用;黄芩汤可降低炎症浸润程度,减少MC数目,降低TA的释放,抑制IL-6的分泌,此可能为黄芩汤治疗湿热型UC的机制.
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