Reaction of the skin fibroblast cytoskeleton to micromanipulation interventions

Micromanipulation is a strong mechanical intervention into cellular integrity and induces large changes in the fine structure of the treated cells. Human diploid skin fibroblasts (KF1 and KF2 cell lines) were chosen as an experimental model. Special hatching needles were used for defined micromanipulation interventions (deformation of plasma membrane). Changes in cytoskeletal structures were visualized by using fluorescent and confocal microscopy. The actin cytoskeleton showed a more sensitive response to micromanipulation than microtubules. Characteristic changes in microfilaments, i.e., thickenings and knot formation, were visible in treated cells fixed immediately after micromanipulation and were the result of hatching-needle pressure on the plasma membrane as well as a reaction of actin filaments localized near the plasma membrane deformation. These direct changes and also other specific alterations in the actin filament network were detectable 14 to 16 h after treatment, but they were not observed when longer reparation intervals were used.