大鼠分泌性中耳炎模型中TNF-α及ICAM-1的免疫组化研究

Rat Model of Otitis Media with Effusion: Immunohistochemical Assay of TNF-α and ICAM-1 Expression

目的 研究肿瘤坏死因子α (TNF α)及细胞间粘附分子 1(ICAM 1)在大鼠分泌性中耳炎模型中耳粘膜中的表达 ,探讨其在分泌性中耳炎发病机制中的作用。方法 取健康SD大鼠 4 0只 ,于左侧中耳注射脂多糖 (LPS) ,并同时切断同侧三叉神经第三支 (下颌神经 )制备大鼠分泌性中耳炎模型。右耳仅向中耳注射磷酸盐缓冲液 (PBS)作为实验对照。术后 3、 7、 14、 30d采集中耳粘膜标本 ,SP法检测中耳粘膜中TNF α及ICAM 1的表达并计算机图像定量分析处理 ,HE染色检查中耳粘膜的病理变化。结果 4个时点组左侧中耳粘膜上皮细胞和血管内皮细胞中TNF α及ICAM 1的表达均较对照组明显增强。 14d组和 30d组TNF α及ICAM 1的阳性表达范围扩大 ,在炎性细胞及成纤维细胞也有大量表达。术后 3d组血管内皮细胞和上皮细胞中TNF α与ICAM 1的表达呈正相关 (r =0 74 ,0 80 ;均为P <0 0 5 )。 3d组及 7d组中ICAM 1在中耳粘膜血管内皮中的表达强度与中性粒细胞浸润程度正性相关。结论 TNF α通过上调ICAM 1的表达 ,从而促进炎性细胞的粘附和聚集 ,二者可能在分泌性中耳炎中耳粘膜的炎症发生发展中起重要作用。

Objective To study the expression of TNF-α and ICAM-1 in middle ear mucosa of rat model of otitis media with effusion and its significance.Methods A rat model of otitis media with effusion was developed by intratympanic injection of E.coli endotoxin and resection of the third branch of the trigeminal nerve (V3). The expression of TNF-α and ICAM-1 in middle ear mucosa from these ears was detected by immunohistochemical SP method and analyzed by computer image system. Results TNF-α and ICAM-1 antigen were observed mainly on epithelial cells and vascular endothelium. The inflammatory cells and fibroblasts were also positive for the expression of TNF-α and ICAM-1 in day 14 group and day 30 group. The intensity of TNF-α staining in vascular endothelium and epithelial cells during early stages was weaker than that during late stages, but the intensity of ICAM-1 staining was weaker during early stages. There was a positive relationship between the expression of TNF-α and that of ICAM-1 in vascular endothelium and epithelial cells in day 3 group (r=0.74, 0.80; P<0.05), and the expression of ICAM-1 in vascular endothelium was positively correlated with neutrophil infiltrition in day 3 group and day 7 group. Conclusion TNF-α can promote adhesion and migration of inflammatory cells through the up-regulation of the ICAM-1 expression in vascular endothelium. TNF-α and ICAM-1 may play an important role in the formation and maintenance of otitis media with effusion.