Carvalho C, Jancar S, Mariano M, Sirois P
Department of Pharmacology, Medical School, University of Sherbrooke, P.Q., Canada.
Exp Lung Res. 1999 Jun;25(4):303-16. doi: 10.1080/019021499270213.
The aim of this study was to examine antigen-induced lung cell migration, eosinophil activation, and pulmonary reactivity of Wistar rats exposed to a new sensitization technique. The animals were sensitized with a single subcutaneous implant of a fragment of heat coagulated hen egg white and challenged 21 days later with an intratracheal injection of heat-aggregated ovalbumin (EWI). For comparison, another group of rats were sensitized by an intraperitoneal injection of ovalbumin in alum as adjuvant, with one booster on day 14 and challenge on day 21 post immunization (OVA/AL). Twenty-four hours after antigen challenge, the EWI group presented a higher number of eosinophils in the bronchoalveolar lavage (BAL) (4.85 +/- 1.43 x 10(6)) than the OVA/AL group (0.2 +/- 0.06 x 10(6)) or the control group, where the level of eosinophils were essentially undetectable. Levels of eosinophil peroxidase activity were increased in the cell-free BAL and homogenates of lung tissue in the EWI group (12.10 +/- 2.97 mg/mL and 36.14 +/- 7.21 ng/mg, respectively), but not in the OVA/AL group (4.83 +/- 1.4 ng/mL and 11.95 +/- 2.54 ng/mg, respectively), as compared with controls (5.16 +/- 1.65 ng/mL and 12.13 +/- 1.74 ng/mg, respectively). Thromboxane B2 levels were also increased in the BAL of EWI group (2.89 +/- 0.54 ng/mL) but not the OVA/AL group (1.13 +/- 0.23 ng/mL) as compared with controls (1.14 +/- 0.19 ng/mL). In contrast, the levels of prostaglandin E2 in the BAL were increased in both groups (456.4 +/- 11.8 pg/mL in the EWI group and 303.5 +/- 31.7 pg/mL in the OVA/AL group) as compared with controls (205.7 +/- 29.7 ng/mL). Moreover, only the EWI group developed increased pulmonary reactivity to serotonin (around two-fold), 24 hours after antigen challenge. The extent of lung eosinophil migration and activation and the pulmonary hyperreactivity induced by this novel sensitization procedure without adjuvants represents a significant improvement over existing experimental models of asthma.
本研究的目的是检测采用一种新致敏技术的Wistar大鼠的抗原诱导的肺细胞迁移、嗜酸性粒细胞活化及肺反应性。用热凝固的鸡蛋清片段单次皮下植入对动物进行致敏，并于21天后用气管内注射热聚集卵清蛋白（EWI）进行激发。作为对照，另一组大鼠通过腹腔注射卵清蛋白（以明矾作为佐剂）进行致敏，在免疫后第14天进行一次加强免疫，并于第21天进行激发（OVA/AL）。抗原激发24小时后，EWI组支气管肺泡灌洗（BAL）中的嗜酸性粒细胞数量（4.85±1.43×10⁶）高于OVA/AL组（0.2±0.06×10⁶）或对照组，对照组中嗜酸性粒细胞水平基本检测不到。EWI组无细胞BAL及肺组织匀浆中嗜酸性粒细胞过氧化物酶活性水平升高（分别为12.10±2.97mg/mL和36.14±7.21ng/mg），而OVA/AL组未升高（分别为4.83±1.4ng/mL和11.95±2.54ng/mg），与对照组相比（分别为5.16±1.65ng/mL和12.13±1.74ng/mg）。EWI组BAL中血栓素B2水平也升高（2.89±0.54ng/mL），而OVA/AL组未升高（1.13±0.23ng/mL），与对照组相比（1.14±0.19ng/mL）。相反，两组BAL中前列腺素E2水平均升高（EWI组为456.4±11.8pg/mL，OVA/AL组为303.5±31.7pg/mL），与对照组相比（205.7±29.7ng/mL）。此外，仅EWI组在抗原激发24小时后对5-羟色胺的肺反应性增加（约两倍）。这种无佐剂的新型致敏程序诱导的肺嗜酸性粒细胞迁移和活化程度以及肺高反应性代表了对现有哮喘实验模型的显著改进。
