Einfluß von Polypropylen-Netzen auf die Proliferation und Apoptose verschiedener humaner Zellkulturen

Abstract

Introduction: Non-resorbable meshes are routinely used for surgical hernia repair to reinforce and stabilize the abdominal wall. Recently, criticism of uncontrolled use of these meshes arose, because the knowledge of foreign-body reactions and neoplastic formation is insufficient. The aim of our study was to investigate the interaction of meshes with human HeLa cells and fibroblasts in vitro. Methods: HeLa cells or human fibroblasts were seeded and cultured over a 48 h period in six-well culture dishes (10⁴,3 x 10⁴,10⁵ cells/well) in an appropriate growth medium on polypropylene meshes (square sheets of 2 x 2 cm²). Controls were seeded without meshes. The cells were treated with trypsin, washed, fixed on slides by cytocentrifugation, followed by immunocytochemical staining with the monoclonal antibody MIB-1 and the StreptABC method (Dako, Glystrup, Denmark). The proliferation index was determined by counting MIB-i stained nuclei. To determine the apoptotic index, washed cells were stained with Annexin V-FITC and propidiumjodide followed by flow cytometric analysis. Results: In comparison to the controls, the proliferation index of fibroblasts incubated with meshes was reduced by only about 6% (64% versus 58%). Interestingly, the proliferation index was increased with decreasing density of the cells: from 46% at 10⁵ cells/well to 71% at 10⁴ cells/well (samples with meshes) and from 55% at 10⁵ cells/well to 78% at 10⁴ cells/well (controls). The apoptotic index of fibroblasts grown with meshes was doubled in comparison to the controls (3.7% versus 1.7%). Additionally, in the mesh group the apoptotic index was elevated with increasing density of the cells: from 2.3% at 10⁴ cells/well to 6.0% at 10⁵ cells/well. The proliferation indices of the HeLa cells were generally higher (90% – 99%), but we could not find any difference between cells grown with or without mesh. The apoptotic index of HeLa cells grown with meshes was elevated by a factor of 7 in comparison to that of the controls (0.5% versus 3.4%). Discussion: Within the selected 48-h period polypropylene meshes had no significant influence on the proliferation index of the investigated cell cultures. However, our results demonstrate that polypropylene meshes have the tendency to increase the apoptotic cell number of the investigated human cells in vitro.