Abraham W M, Oliver W, Welker M J, King M M, Wanner A, Sackner M A
J Appl Physiol Respir Environ Exerc Physiol. 1981 Dec;51(6):1651-6. doi: 10.1152/jappl.1981.51.6.1651.
The effect of breathing 5 ppm sulfur dioxide (SO2) on airway reactivity was studied in both normal and allergic conscious sheep. Allergic sheep were defined as animals in which inhalation of Ascaris suum extract resulted in bronchospasm as evidenced by an increase in mean pulmonary flow resistance (RL), hyperinflation, and a fall in dynamic compliance. Airway reactivity was assessed by measuring the increase of RL after 18 breaths of 0.25% carbachol (c), from an initial RL value obtained after 18 breaths of buffered saline (s) [RL(c-s)]. RL and RL(c-s) were determined prior to, immediately after, and 24 h after exposure to 5 ppm SO4 for 4 h. In both groups RL remained unchanged after SO2 exposure. Prior to exposure, RL(c-s) was not significantly different in seven normal (0.3 +/- 0.1) and seven allergic sheep [0.4 +/- 0.2 (SD) cmH2O X l-1 X s], and there was no significant change in RL (c-s) immediately after SO2 exposure in either group. Twenty-four h later, RL(c-s) RL(c-s) increased to 0.7 +/- 0.8 (P less than 0.2) in normal and to 1.8 +/- 0.9 cmH2O X l-1 X s (P less than 0.01) in allergic sheep. Because the increase in RL(c-s) after 24 h was greater (P less than 0.01) in allergic than in normal sheep, we conclude that SO2 exposure increased airway reactivity more in the former than in the latter.
在正常和过敏的清醒绵羊中研究了呼吸5 ppm二氧化硫（SO₂）对气道反应性的影响。过敏绵羊定义为吸入猪蛔虫提取物后出现支气管痉挛的动物，这可通过平均肺血流阻力（RL）增加、肺过度充气和动态顺应性下降来证明。通过测量吸入0.25%卡巴胆碱（c）18次呼吸后RL的增加来评估气道反应性，初始RL值是在吸入缓冲盐水（s）18次呼吸后获得的[RL（c-s）]。在暴露于5 ppm SO₂ 4小时之前、之后立即以及24小时后测定RL和RL（c-s）。两组在暴露于SO₂后RL均保持不变。暴露前，7只正常绵羊[0.3±0.1]和7只过敏绵羊[0.4±0.2（标准差）cmH₂O×l⁻¹×s]的RL（c-s）无显著差异，且两组在暴露于SO₂后立即RL（c-s）均无显著变化。24小时后，正常绵羊的RL（c-s）增加到0.7±0.8（P＜0.2），过敏绵羊的RL（c-s）增加到1.8±0.9 cmH₂O×l⁻¹×s（P＜0.01）。由于24小时后过敏绵羊的RL（c-s）增加幅度（P＜0.01）大于正常绵羊，我们得出结论，暴露于SO₂后，前者的气道反应性增加幅度大于后者。
