Ⅱ型超敏反应家兔模型的建立

Establishment of rabbit model of typeⅡ hypersensitivity

目的建立Ⅱ型超敏反应家兔模型,为免疫毒理学或药效学研究提供新方法。方法家兔耳缘静脉注射绵羊红细胞(SRBC)5×108kg-1,每天1次,每周连续6d,停药1d,连续6周,诱导Ⅱ型超敏反应。每周观察呼吸和喷嚏等症状,并监测体温,检测血清游离血红蛋白和游离胆红素及尿隐血,计数外周血网织红细胞、中性粒细胞、淋巴细胞和血小板,测定血清谷丙转氨酶(GPT)和谷草转氨酶(GOT)活性及尿素氮和肌酐浓度,用Coombs实验法检测血清抗SRBC抗体水平。6周后处死家兔,测定肝、肾、脾和胸腺指数,并观察组织病理变化。结果与对照组相比,注射SRBC后1～6周,家兔呼吸和喷嚏等症状及体温未见明显变化,外周血网织红细胞数目和血清游离胆红素浓度未见明显变化。但从第1周开始出现尿隐血,第5周时血清游离血红蛋白显著增加,提示出现血管内溶血。外周血淋巴细胞从第1周开始显著增加,第4周时中性粒细胞明显减少,血小板数目未见明显变化,提示粒细胞受损伤。第1和第2周时血清GPT活性增加,第6周时GOT活性增加,尿素氮和肌酐水平未见明显变化。第3周时血清中出现抗SRBC抗体,第6周时脾脏和胸腺显著肿大,提示免疫系统参与此过程。第6周时肾脏、脾脏和胸腺组织未见明显变化,肝脏组织出现肝小叶排列紊乱、炎症细胞浸润和大量空泡等现象,提示肝脏有变性性损伤。结论家兔耳缘静脉注射SRBC6周可导致Ⅱ型超敏反应。

OBJECTIVE To establish a rabbit model of typeⅡ hypersensitivity as a new approach to immune toxicology or pharmacodynamic study. METHODS The rabbits were intravenously injected with sheep red blood cells (SRBC) 5×108 kg-1 through the edge of the ear once a day for 6 d in a week, for 6 weeks, to induce typeⅡ hypersensitivity. The responses of the immune system, such as respiration difficulty and sneezing, were observed, and body temperature was determined every week. The serum levels of free hemoglobin, unconjugated bilirubin, urea nitrogen and creatinine, activities of glutamic-pyruvic transaminase (GPT) and glutamic-oxalacetic transaminase (GOT), and counts of granulofilocytes, neutrophils and platelets in peripheral blood were determined every week. The urine collected each week was used to analyze occult blood. Coombs test was used to determine whether the rabbit serum could cause the hemolysis of SRBC in vitro. After 6 weeks, the rabbits were sacrificed for the liver, kidneys, spleen and thymus. Organ weight indexes were counted and histopathological examination was performed. RESULTS Compared with control group, the symptoms of the respiratory system, body temperature, granulofilocyte count and the unconjugated bilirubin level of rabbits were not obviously changed after injection of SRBC. Occult blood in urine was present from the 1st week after injection with SRBC and free hemoglobin was obviously increased after injection with SRBC for 5 weeks, suggesting the occurrence of intravascular hemolysis. Neutrophils were significantly decreased from the 1st week and lymphocytes were significantly increased from the 4th week compared with control group, while platelet count was not changed significantly, suggesting that the granulocytes were injured. GPT activity was increased on the 1st and 2nd week, and GOT activity was increased on the 6th week, while urea nitrogen and creatinine concentrations were not changed. The antibody against SRBC was present in the serum of rabbits injected with SRBC and caused SRBC hemolysis in vitro on the 3rd week, and spleen and thymus indexes were increased on the 6th week, which indicated the involvement of the immune system in this hypersensitivity. Histopathological changes in the spleen, thymus and kidneys were not observed, while the liver tissue showed disorder of hepatic lobules, infiltrated inflammatory cells and vacuolis, indicating that the liver was injured. CONCLUSION Rabbits injected with SRBC for 6 weeks can induce typeⅡ hypersensitivity.