HEMOSTATIC SYSTEM ALTERATIONS INDUCED BY NEUWIEDASE: A METALLOPROTEINASE ISOLATED FROM SNAKE VENOM Bothrops neuwiedi

Rodrigues, V.M.; Izidoro, L.F.M.; Rodrigues, R.S.; Hamaguchi, A.; Homsi-Brandeburgo, M. I.

Institute of Genetic and Biochemistry, Universidade Federal de Uberlândia, Minas Gerais, Brasil.

Snake venoms of several species cause changes in the hemostatic system, by interfering with platelet function, damaging blood vessels and activating coagulation factors such as prothrombin, factor IX and fibrinogen. Neuwiedase is a 22 kDa class P-I metalloproteinase isolated from the venom  of the B. neuwiedi. It is able to induce myotoxicity, edema and bleeding pulmonary. In this work we analysed the disturbance induced by the whole venom and neuwiedase on hemostatic system. Mice male (n=5, 25g) received 0,6 LD₅₀ of neuwiedase(LD₅₀= 5,0mg/kg)  or 0,6 LD₅₀ of whole venom (LD₅₀=1,66mg/kg) by the i.p. route. Venom and neuwiedase were dissolved in 100ml PBS. Control mice received PBS alone. After 6 hours each animal was sacrificed and blood collected by puncture cardiac in presence or ausence of anticoagulant for quantitative analysis of red cells, hemoglobin, platelets (at equipment Coulter T-890), prothrombin and thrombin time, plasmatic fibrinogen concentration (at equipment Thrombolizer Compact) and whole blood coagulation time (at room temperature). The neuwiedase induced  a significant decrease only of platelets (p<0,05 test t Student) and whole venom caused a reduction of platelets, red cells and hemoglobin (p<0,05 test t Student). An significant increase of prothrombin, thrombin and  blood coagulation time was observed when the whole venom or neuwiedase were injected by i.p route  at  different inoculations time. Neuwiedase degraded  83% of plasmatic fibrinogen, however whole venom was capable to degraded only 35% when compared with control (PBS). The neuwiedase is a important metalloproteinase from the B. neuwiedi snake venom, by interfering with the normal hemostatic mechanisms. It showed action on proteins and cellular elements in blood, suggesting its potential use as an therapeutical agent  for the treatment of human diseases.

CORRESPONDENCE TO:

Rodrigues, V.M, Institute of Genetic and Biochemistry, Universidade Federal de Uberlândia, Minas Gerais, Brazil. CEP  38400-902, Email: veridiana_avila@hotmail.com