Figure 1.

Myotoxic and cytotoxic activities of MjTX-II in mice and cultured C₂C₁₂ myoblasts, respectively, and their inhibition by preincubation with Varespladib. (A) Mice were injected by intramuscular route with toxin alone (50 μg, in 100 μL of PBS), or preincubated for 15 min with Varespladib (VAR) at a final concentration of 400 μM. Control groups were injected with PBS alone or Varespladib alone, respectively. After 3 hr, blood was obtained and the plasma creatine kinase (CK) activity was determined, as described in Methods. Each bar represents the mean ± SD of 4–5 mice per group. (B) Cells were exposed to the toxin alone (20 μg, in 150 μL of medium), or preincubated for 15 min with Varespladib (VAR) at a final concentration of 400 μM. After incubating the cells for 3 hr at 37 °C, an aliquot of supernatant was assayed for lactate dehydrogenase (LDH) activity, as described in Methods. Cytotoxicity is expressed as percentage, considering the LDH activity of cells exposed to medium with 0.1% Triton X-100, or to medium alone, as 100% and 0%, respectively. Each bar represents the mean ± SD of three replicates. Statistically significant (p < 0.05) differences between values obtained with the toxin alone or the toxin preincubated with Varespladib are indicated by an asterisk.