Pathological alterations induced by neuwiedase, a metalloproteinase isolated from Bothrops neuwiedi snake venom

The pathological alterations induced by neuwiedase, a 22 kDa class P-1 meta lloproteinase from the venom of the South American pit viper Bothrops neuwi edi, were studied in mice. Neuwiedase was devoid of hemorrhagic activity wh en tested in the skin up to a dose of 200 mug, and also after intramuscular injection in the gastroenemius. However, it induced bleeding when applied onto the mouse cremaster muscle in intravital microscopy experiments, and c aused pulmonary hemorrhage when injected intravenously at doses higher than 5 mug/g. Median lethal dose (LD50) by the intravenous route was 5 mug/g, w hereas LD50 of crude venom was 0.47 mug/g. After intramuscular injection, n euwiedase induced a mild myotoxic effect, evidenced histologically and by t he increment in plasma creatine kinase activity, but it was devoid of hemor rhagic and thrombotic effects. In contrast, crude B. neuwiedi venom induced prominent hemorrhage and myonecrosis in gastrocnemius muscle. Both venom a nd neuwiedase induced an inflammatory reaction in muscle tissue characteriz ed by abundant polymorphonuclear leukocytes. Moreover, a conspicuous edema developed in the foot pad after subcutaneous injection of neuwiedase. Anti- neuwiedase antibodies produced in rabbits were effective in the neutralizat ion of hemorrhagic activity of crude venom, evidencing immunological cross- reactivity between neuwiedase and other hemorrhagic metalloproteinases pres ent in the venom, and suggesting that metalloproteinases devoid of, or havi ng low, hemorrhagic activity could be good immunogens to generate antibodie s effective against high molecular mass metalloproteinasas having potent he morrhagic activity. It is concluded that neuwiedase, despite its lack of he morrhagic effect when injected in the gastrocnemius muscle, contributes to local tissue damage by inducing edema, inflammatory infiltrate and mild myo toxicity, and by degrading extracellular matrix components. In addition, la rge doses of neuwiedase may contribute to pulmonary bleeding (C) 2001 Socie te francaise de biochimie et biologic moleculaire / Editions scientifiques et medicales Elsevier SAS. All rights reserved.