Stone P J, Calore J D, Snider G L, Franzblau C
J Clin Invest. 1982 Apr;69(4):920-31. doi: 10.1172/jci110531.
Radiolabeled, enzymatically active or chloromethyl ketone-inactivated porcine pancreatic elastase was endotracheally instilled into hamsters. Gel filtration of the bronchopulmonary lavage fluid revealed two major radioactive fractions: one, eluting at 780,000 daltons, corresponding to an alpha-macroglobulin-pancreatic elastase complex, and another, at 68,000 daltons, corresponding to an alpha-1-protease inhibitor-pancreatic elastase complex. Elastolytic activity was recovered in the bronchopulmonary lavage fluid up to 4 d after elastase instillation and was associated with the alpha-macroglobulin-pancreatic elastase complex. Small amounts of this complex were recovered 14 d after instillation. When less than 1% (1.5--1.7 micrograms) of the usual dose of elastase was instilled into hamsters, the major radioactive complex was alpha-1-protease inhibitor-pancreatic elastase complex, and little or no elastolytic activity was found in the lavage fluid. In contrast to the instillation of 220 micrograms of elastase, no disease or hemorrhagic reaction was detected with this low dose, and without hemorrhage only insignificant amounts of alpha-macroglobulin-pancreatic elastase complexes were recovered from the lungs. To study the interaction of circulating antiproteases with elastase, hamster plasma was allowed to interact directly with the radiolabeled elastase; alpha-macroglobulin bound much more of the elastase than alpha-1-protease inhibitor, confirming the findings in the lung lavage experiments. The hamster's susceptibility to pancreatic elastase-induced emphysema may depend on the preferential binding of elastase to alpha-macroglobulin, which protects the elastolytic potential, rather than to alpha-1-protease inhibitor, which inactivates elastase. We speculate that if even a fraction of the residual radioactivity found in the hamster lungs as long as 144 d after instillation of elastase represents enzymatically active alpha-macroglobulin-pancreatic elastase complex, this could serve as a source of persistent elastolytic activity, which might explain the progressive nature of the pulmonary lesion.
将放射性标记的、具有酶活性或经氯甲基酮失活的猪胰弹性蛋白酶经气管内注入仓鼠体内。对支气管肺泡灌洗液进行凝胶过滤，发现有两个主要的放射性组分：一个在780,000道尔顿处洗脱，对应于α-巨球蛋白-胰弹性蛋白酶复合物；另一个在68,000道尔顿处，对应于α-1-蛋白酶抑制剂-胰弹性蛋白酶复合物。弹性蛋白酶注入后长达4天，支气管肺泡灌洗液中均可检测到弹性溶解活性，且与α-巨球蛋白-胰弹性蛋白酶复合物相关。注入后14天可回收少量该复合物。当向仓鼠注入少于通常剂量1%（1.5 - 1.7微克）的弹性蛋白酶时，主要的放射性复合物为α-1-蛋白酶抑制剂-胰弹性蛋白酶复合物，灌洗液中几乎未发现弹性溶解活性。与注入220微克弹性蛋白酶相比，低剂量注入未检测到疾病或出血反应，且无出血情况下，从肺中仅回收了少量的α-巨球蛋白-胰弹性蛋白酶复合物。为研究循环抗蛋白酶与弹性蛋白酶的相互作用，使仓鼠血浆直接与放射性标记的弹性蛋白酶相互作用；α-巨球蛋白结合的弹性蛋白酶比α-1-蛋白酶抑制剂多得多，这证实了肺灌洗实验的结果。仓鼠对胰弹性蛋白酶诱导的肺气肿的易感性可能取决于弹性蛋白酶与α-巨球蛋白的优先结合，α-巨球蛋白可保护弹性溶解潜能，而非与使弹性蛋白酶失活的α-1-蛋白酶抑制剂结合。我们推测，即使在弹性蛋白酶注入后长达14天在仓鼠肺中发现的残余放射性的一小部分代表具有酶活性的α-巨球蛋白-胰弹性蛋白酶复合物，这也可能是持续弹性溶解活性的来源，这或许可以解释肺部病变的进展性质。
