Evidence of participation of cytoskeleton of heart muscle cells during the invasion of Trypanosoma cruzi.

The participation of heart muscle cells (HMC) cytoskeleton during its interaction with Trypanosoma cruzi was investigated. Pre-treatment of heart muscle cells with cytochalasin B (CB) or D (CD) prior to 1 and 3 h of interaction with T. cruzi inhibited the uptake of parasites by about 65% and 75%. T. cruzi was not able to invade fixed HMC, and fixed parasites were not internalized in either normal and CD-treated HMC. Transmission electron microscopy showed cell membrane projections of HMC enclosing the parasite during the invasion process after short periods of interaction (5 to 30 min). During the parasite internalization process, sarcolemma extensions were observed inside the cytoplasmic vacuole, suggesting that the endocytic event may involve internalization of a "self membrane". Images of cytoskeleton elements mobilization during T. cruzi penetration of HMC were obtained following treatment of cells with Triton X-100. Our results suggest an active involvement of HMC cytoskeleton elements during the interiorization of metacyclic forms of T. cruzi.