Myotoxic Effect Of Different Venoms On Mice Skeletal Muscle. 

Tomaz, M.A. , Calil-Elias, S., Fernandes, F.FA., Moraes, R.A.M., Pinheiro, D.A, Oliveira, J.S., Melo, P.A.

Depto. Farmacologia Básica e Clínica, UFRJ.

We studied the effect of the venoms from snakes Bothropsjararacussu, Agkistrodon contortrix laticinctus (ACL), Crotalus viridis viridis (CVV) e Crotalusdurissus terrificus (CDT), and the bee Apismeliffera on fast-, Extensor digitorum longus (EDL) and slow-twitch muscles, Soleus(SOL). Miotoxicity was assessed in vitro by the rate of creatine kinase (CK - U.g^-1.h^-1) release from the isolated muscles (N= 4-12). These were perfused with plysiological saline solution (PSS) in the absence or in the presence of the venoms (25 mg/ml). The basal rate of CK release varied from 0.25 a 0.36 ±0.04. The rate of CK release following 60 minutes of exposure to the venoms of B. jararacussu, ACL, CVV, CDT and A. meliffera were 13.7±2.5, 12.9±4.1, 5.1±1.3 and 13.1±3.4, 19.7±1.9, from EDL, and 3.0±0.9, 0.5±0.5, 0.3±0.3 e 2.0±0.9, 13.4±1.6, from SOL, respectively. The effect of denervation of the muscles by the sectioning of the sciatic nerve was also studied. We found a reduction of 39%, 47% and 76% in EDL CK content, and 60%, 70% e 88% in SOL CK content, compared to control, after 7, 14 and 27 days of denervation, respectively. Muscles were exposed to B. jararacussu venom 7, 14 and 21 days after denervation, and the rate of CK release after 60 minutes of exposure were 9.6±2.1, 5.1±1.4 and 3.1±0.7, from EDL, and 2.3±0.3, 0.1±0.02 and 0.05±0.05, from SOL, respectively. These data show that EDL presents a greater rise in the rate of CK release after exposure to the venoms studied than does SOL, even after denervation, which indicates that the type of innervation is not the factor responsible for the different responses found.

Support: CNPq, FAPERJ, FUJB, CAPES, PRONEX.

Correspondence to: sabrina_calil@uol.com.br