Specific interaction of pancreatic elastase and leukocytes to produce oxygen radicals and its implication in pancreatitis

许多先前使用胰腺炎实验动物模型的报道表明，氧自由基在胰腺炎的发生和发展中起重要作用。在动物模型和胰腺炎患者的胰腺损伤中均可见到中性粒细胞、淋巴细胞和单核细胞等炎性细胞的浸润。在这些炎症细胞中，中性粒细胞是产生氧自由基最多的细胞，似乎中性粒细胞产生的氧自由基在胰腺炎中具有一定的病理意义。在本研究中，我们测量了急性和慢性胰腺炎患者的营养粒细胞产生的超氧化物，然后检查了胰酶对超氧化物产生的影响。4 -phorbol 12 -肉豆蔻酸13 - α -醋酸酯（PMA）刺激的中性粒细胞产生的超氧化物明显高于健康对照组。在淀粉酶、胰蛋白酶和弹性酶三种胰腺酶中，弹性酶是唯一能使pma刺激的中性粒细胞产生超氧化物的酶，增加了1.5倍。它还使由pma刺激的中性粒细胞制备的NADPH氧化酶的活性增加了2.1倍。确定了弹性蛋白酶在中性粒细胞上的高亲和力和低亲和力结合位点。这些结果表明，弹性蛋白酶通过促进中性粒细胞的超氧化物产生在胰腺炎的发展中起作用。

Many previous reports using experimental animal models of pancreatitis have suggested that oxygen free radicals plays an important role in initiation and development of pancreatitis. Infiltration of inflammatory cells, i.e., neutrophils, lymphocytes and monocytes, has been observed in damaged pancreatic glands of animal models and patients of pancreatitis. Neutrophils are known to be the highest producer of oxygen free radicals among these inflammatory cells, it seems plausible that oxygen free radicals produced by neutrophils have some pathoetiological meaning in pancreatitis. In the present study we measured the superoxide production by nutrophils obtained from patients with acute and chronic pancreatitis, and then examined the effects of pancreatic enzymes on superoxide production. Patients showed significantly higher superoxide production by 4beta-phorbol 12beta-myristate 13alpha-acetate (PMA)-stimulated neutrophils than healthy controls did. Among the three pancrestic enzymes, amylase, trypsin and elastase, elastase was the only one which increased the superoxide production by PMA-stimulated neutrophils, by an increment of 1.5-fold. It also increased the activity of NADPH oxidase prepared from PMA-stimulated neutrophils by a factor of 2.1. High affinity and low affinity binding sites fot elastase on neutrophils were identified. These results suggest that elastase plays a role in the development of pancreatitis by enhancing superoxide production of neutrophils.