Landucci E C, Castro R C, Pereira M F, Cintra A C, Giglio J R, Marangoni S, Oliveira B, Cirino G, Antunes E, De Nucci G
Department of Pharmacology, Faculty of Medical Sciences, UNICAMP, Campinas (SP), Brazil.
Eur J Pharmacol. 1998 Feb 19;343(2-3):257-63. doi: 10.1016/s0014-2999(97)01546-x.
Bothropstoxin-I and bothropstoxin-II are phospholipase A2 homologues isolated from Bothrops jararacussu snake venom. The former is devoid of phospholipase A2 activity whereas the latter has very low enzymatic activity. In this study, we have investigated the in vivo (rat paw and skin oedema) and in vitro (mast cell degranulation) inflammatory effects caused by bothropstoxin-I and bothropstoxin-II. Bothropstoxin-I (25-100 microg/paw) and bothropstoxin-II (12.5-50 microg/paw) caused dose-dependent rat paw oedema. The intradermal injection of bothropstoxin-I (0.125-5 microg/site) and bothropstoxin-II (0.125-5 microg/site) into rat skin also resulted in dose-dependent oedema formation. These oedematogenic activities were largely reduced in animals pretreated with the histamine/5-hydroxytryptamine (5-HT) receptor antagonist cyproheptadine (2 mg/kg, i.p. 0.5 h before). Similarly, p-bromophenacyl bromide, a compound known to inhibit phospholipase A2 activity, significantly inhibited rat paw and skin oedema induced by both phospholipase A2 homologues. The polyanion heparin (5 IU/site) significantly reduced the rat skin oedema induced by either bothropstoxin-I or bothropstoxin-II as well as the paw oedema (50 IU/site) induced by the former. When assayed in the rat peritoneal mast cells in vitro, both bothropstoxin-I (10 and 100 microg/ml) and bothropstoxin-II (3 and 10 microg/ml) significantly caused [14C]5-HT release. The [14C]5-HT release caused by these phospholipase A2 homologues were reduced by p-bromophenacyl bromide and heparin (50 IU/ml). Our results indicate that oedema formation induced by bothropstoxin-I and bothropstoxin-II is mostly dependent on in vivo mast cell degranulation. Since heparin greatly reduced the oedematogenic activity of these phospholipase A2 homologues, it is likely that the cationic charge of these substances plays a major role in the mast cell activation. Our results also indicate that p-bromophenacyl bromide may not be a suitable pharmacological tool to investigate the correlation between enzymatic activity and the inflammatory effects of phospholipases A2.
矛头蝮毒素 -I和矛头蝮毒素-II是从巴西矛头蝮蛇毒中分离出的磷脂酶A2同系物。前者缺乏磷脂酶A2活性，而后者的酶活性非常低。在本研究中，我们调查了矛头蝮毒素-I和矛头蝮毒素-II引起的体内（大鼠足爪和皮肤水肿）和体外（肥大细胞脱颗粒）炎症效应。矛头蝮毒素-I（25 - 100微克/足爪）和矛头蝮毒素-II（12.5 - 50微克/足爪）引起剂量依赖性的大鼠足爪水肿。将矛头蝮毒素-I（0.125 - 5微克/部位）和矛头蝮毒素-II（0.125 - 5微克/部位）皮内注射到大鼠皮肤中也导致剂量依赖性的水肿形成。在用组胺/5 - 羟色胺（5 - HT）受体拮抗剂赛庚啶（2毫克/千克，腹腔注射，提前0.5小时）预处理的动物中，这些致水肿活性大大降低。同样，已知能抑制磷脂酶A2活性的对溴苯甲酰溴显著抑制了由这两种磷脂酶A2同系物诱导的大鼠足爪和皮肤水肿。聚阴离子肝素（5国际单位/部位）显著减轻了由矛头蝮毒素-I或矛头蝮毒素-II诱导的大鼠皮肤水肿以及由前者诱导的足爪水肿（50国际单位/部位）。当在大鼠腹腔肥大细胞中进行体外测定时，矛头蝮毒素-I（10和100微克/毫升）和矛头蝮毒素-II（3和10微克/毫升）均显著引起[14C]5 - HT释放。对溴苯甲酰溴和肝素（50国际单位/毫升）减少了由这些磷脂酶A2同系物引起的[14C]5 - HT释放。我们的结果表明，矛头蝮毒素-I和矛头蝮毒素-II诱导的水肿形成主要依赖于体内肥大细胞脱颗粒。由于肝素大大降低了这些磷脂酶A2同系物的致水肿活性，这些物质的阳离子电荷可能在肥大细胞激活中起主要作用。我们的结果还表明，对溴苯甲酰溴可能不是研究磷脂酶A2的酶活性与炎症效应之间相关性的合适药理学工具。
