Insights of local tissue damage and regeneration induced by BnSP-7, a myotoxin isolated from Bothrops (neuwiedi) pauloensis snake venom

Envenomations caused by Bothrops snake venoms are characterized by prominent local tissue damage due to myonecrosis, hemorrhage, edema and acute muscle damage which is widely correlated with phospholipases A₂ (PLA₂). In the present study, the progression of local tissue damage and inflammation induced by BnSP-7, a myotoxin isolated from Bothrops (neuwiedi) pauloensis snake venom, was evaluated. Local tissue damages characterized by edema, necrosis and inflammation were evaluated until 24 h after inoculation of BnSP-7. The regeneration of myofibers, analyzed by light microscopy, was observed from 72 h to 2 weeks post-inoculation of toxin. MMP-2 was expressed in gastrocnemius muscle at all time points tested, while the expression of MMP-9 increased expressively at the same time interval of regenerating muscle, suggesting the involvement of MMP-9 in the regeneration process. The production of pro-inflammatory cytokines was also increased, whereas IL-1β showed the highest level. Modification of BnSP-7 with BPB decreased the release of IL-8, IL-6 and IL-1β when compared to native BnSP-7. These data suggest that BnSP-7 acts as pro-inflammatory incentives (mediators), inducing MMP and cytokine production from the inflammatory and satellite cells, and thus it may play an important role in inflammatory process and, consequently, in the evolution of local tissue damage and regeneration.