Slocombe R F, Malark J, Ingersoll R, Derksen F J, Robinson N E
Am J Vet Res. 1985 Nov;46(11):2253-8.
Acute lung injury was induced in 24 calves by intratracheal inoculation with Pasteurella haemolytica. Calves in groups 1 and 2 were neutrophil depleted, using hydroxyurea given IV. Group 1 calves (n = 7) were inoculated intratracheally with saline solution, and group 2 calves (n = 7) were inoculated with P haemolytica. Group 3 calves (n = 7) had normal numbers of neutrophils and were inoculated with P haemolytica. Group 4 calves (n = 3) were treated acutely with hydroxyurea IV, had normal numbers of neutrophils, and were inoculated with P haemolytica. After inoculation, calves with normal numbers of neutrophils (groups 3 and 4) became hypoxemic 2 hours after inoculation, and hypoxemia persisted until necropsy (6 hours after inoculation). These calves also developed tachypnea, bradycardia, neutropenia, and lymphopenia. Lung lesions consisted of necrosis of the alveolar walls, intra-alveolar hemorrhage, and a severe exudative and necrotizing bronchopneumonia, with accumulation of proteinaceous fluid in alveoli and lymphatics. In neutrophil-depleted calves (groups 1 and 2), blood gas values, heart and respiratory rates, and numbers of circulating leukocytes did not change after inoculation with saline solution or with P haemolytica. At necropsy, the lungs of neutrophil-depleted calves were grossly normal. Therefore, neutrophils were required for the acute lung injury induced by P haemolytica. The protective effect of neutrophil depletion was a specific effect of hydroxyurea because calves with high circulating concentrations of hydroxyurea and calves with normal numbers of neutrophils (group 4) developed lung injury.
通过气管内接种溶血巴斯德氏菌在24头犊牛中诱发急性肺损伤。第1组和第2组的犊牛通过静脉注射羟基脲使中性粒细胞减少。第1组犊牛（n = 7）气管内接种盐溶液，第2组犊牛（n = 7）接种溶血巴斯德氏菌。第3组犊牛（n = 7）中性粒细胞数量正常，接种溶血巴斯德氏菌。第4组犊牛（n = 3）通过静脉注射羟基脲进行急性处理，中性粒细胞数量正常，接种溶血巴斯德氏菌。接种后，中性粒细胞数量正常的犊牛（第3组和第4组）在接种后2小时出现低氧血症，低氧血症持续至尸检（接种后6小时）。这些犊牛还出现呼吸急促、心动过缓、中性粒细胞减少和淋巴细胞减少。肺部病变包括肺泡壁坏死、肺泡内出血以及严重的渗出性和坏死性支气管肺炎，肺泡和淋巴管内有蛋白质液体蓄积。在中性粒细胞减少的犊牛（第1组和第2组）中，接种盐溶液或溶血巴斯德氏菌后血气值、心率和呼吸频率以及循环白细胞数量均未改变。尸检时，中性粒细胞减少的犊牛的肺大体正常。因此，溶血巴斯德氏菌诱发的急性肺损伤需要中性粒细胞。中性粒细胞减少的保护作用是羟基脲的特异性作用，因为羟基脲循环浓度高的犊牛和中性粒细胞数量正常的犊牛（第4组）发生了肺损伤。
